JP3613454B2 - Compiler device and computer-readable recording medium storing compiler - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a compiler that interprets a source program, generates intermediate text, performs optimization, and generates an object program. For more details on the device Execute optimization based on deletion of conditional branches in the loop (optimization to reduce the execution time of the object program to be generated) Compiler device About.
[0002]
[Prior art]
This kind of traditional Compiler device Japanese Patent Laid-Open No. 5-27986 discloses a patent publication relating to the above.
[0003]
In this publication, a comparison instruction is given when there is a conditional branch that branches based on the result of comparing a constant that is invariant in a loop or a variable that is invariant in a loop and that is based on the comparison result. A technique (optimization method and optimization apparatus of a compiler) that realizes optimization by deleting and branching unconditionally to a branch destination is described.
[0004]
That is, in this prior art, only a comparison instruction between a variable that is invariant in a loop and a constant or a comparison instruction between variables that is invariant in a loop is changed to an unconditional branch instruction, and the conditional branch in the loop is deleted. Optimization has been done.
[0005]
Here, in the related art, a branch instruction (unconditional branch instruction replaced from a comparison instruction and a conditional branch instruction) for determining whether or not to execute an expression executed only under a specific condition in a loop. ) Had to be generated.
[0006]
[Problems to be solved by the invention]
Conventional as described above Compiler device Has the following problems.
[0007]
The first problem is that a branch instruction (unconditional branch instruction) for determining whether to execute an expression executed only under a specific condition in a loop is generated. That is, there is a possibility of inhibiting the conversion.
[0008]
The second problem is that since the branch instruction mentioned in the first problem is always generated, more instructions are executed in the loop. Compiler device This means that the execution performance of the object program generated by the process deteriorates.
[0009]
In view of the above points, the object of the present invention is to change a conditional branch (conditional branch code) existing in a loop to an unconditional branch (unconditional branch code) by unrolling the loop. A compiler that can generate an object program with a short execution time by deleting unnecessary code based on Computer-readable recording medium storing device and compiler Is to provide.
[0010]
[Means for Solving the Problems]
Of the present invention Compiler device Is a compiler that interprets a source program, generates intermediate text, optimizes it, and generates an object program Device, wherein said optimization is Optimization based on deleting conditional branches in a loop And the compiler device is Loop detection means for detecting a loop including an index having an initial value of 1 and an increment value of 1, and a conditional branch code existing in the loop detected by the loop detection means are detected. Is a comparison with a constant, and a condition branch code that satisfies the requirement that the dividend for division to calculate the remainder is an index of the loop and the division divisor is a positive integer constant is detected and the condition Branch detection means for recording information relating to the branch code, the number of unroll stages of the loop including the conditional branch code detected by the branch detection means, the divisor in the information recorded by the branch detection means, and the number of repetitions of the loop The unroll stage number determining means for determining the value of the greatest common divisor with (the number of repetitions) and the unroll stage number determined by the unroll stage number determining means In the process of unrolling and unrolling each code in the unrolling, the branch detection is performed based on the information indicating the number of stages in which each code is expanded and the information recorded by the branch detection unit. The condition of the conditional branch code detected by the means is determined to be “whether it will be true / false” or “whether it will be true or false”, and based on the determination, the condition must be true / false. Loop unrolling means for changing conditional branch code to unconditional branch code, and unnecessary code deletion for deleting unnecessary code due to change from conditional branch code to unconditional branch code by the loop unrolling means Means.
[0011]
In addition, the present invention Compiler device Is a compiler that interprets a source program, generates intermediate text, optimizes it, and generates an object program Device, wherein said optimization is Optimization based on deleting conditional branches in a loop And the compiler device is A loop detection means for detecting a loop including an index whose initial value is a variable (including a constant other than 1) and an increment value is 1, and a conditional branch code existing in the loop detected by the loop detection means is detected. Satisfying the requirement that the condition is a comparison between the result of the remainder and a constant, the dividend of the division for calculating the remainder is an index of the loop, and the divisor of the division is a positive integer constant. A branch detection unit that detects a conditional branch code and records information related to the conditional branch code, and an unrolled stage number of a loop including the conditional branch code detected by the branch detection unit in the information recorded by the branch detection unit The unroll stage number determining means for determining the divisor value and the unroll target code group (the number of loop iterations is determined by the unroll stage number determining means). Code group divided as a code group other than the unroll target code group) is generated in the previous stage of the unroll target code group when it is adjusted to be as large as possible by a multiple of the unrolled stage number , Information indicating in which stage each code is unrolled in the process of unrolling the loop with the unroll stage number determined by the unroll stage number determining means and developing each code in the unrolling stage And “whether it will be true / false” or “whether it will be true or false” for the condition of the conditional branch code detected by the branch detection means from the information recorded by the branch detection means A loop unrolling means for determining and changing a conditional branch code whose condition is always true / false based on the determination to an unconditional branch code; It may be configured to have a dead code deleting means from the conditional branch code by loop unrolling means due to changes to the unconditional branch code to delete the code becomes unnecessary.
[0012]
Furthermore, the present invention Compiler device Is a compiler that interprets a source program, generates intermediate text, optimizes it, and generates an object program Device, wherein said optimization is Optimization based on deleting conditional branches in a loop And the compiler device is Loop detecting means for detecting a loop including an index having an initial value of 1 and an increment value being a constant, and a conditional branch code existing in the loop detected by the loop detecting means are detected. Is a comparison with a constant, and a condition branch code that satisfies the requirement that the dividend for division to calculate the remainder is an index of the loop and the division divisor is a positive integer constant is detected and the condition Based on the information recorded by the branch detection means, the branch detection means for recording information related to the branch code, and the number of unroll stages of the loop including the conditional branch code detected by the branch detection means After unrolling Increment value of Before unrolling Value that satisfies the requirement that it is the least common multiple of the increment value of Divided by the incremental value before unrolling Unrolling stage number determining means for determining to be, and unrolling of the loop with the unrolling stage number determined by the unrolling stage number determining means, and in the process of developing each code in the unrolling, The condition branch code condition detected by the branch detection means based on the information indicating whether the code is expanded into the information and the information recorded by the branch detection means is “whether it is always true / false” and “ A loop unrolling means that determines whether the condition branch code is true / false based on the determination, and changes the conditional branch code that is always true / false to an unconditional branch code, and the loop unrolling means It has unnecessary code deletion means that deletes code that has become unnecessary due to the change from conditional branch code to unconditional branch code. It can also be configured to.
[0013]
In addition, the present invention Compiler device Is a compiler that interprets a source program, generates intermediate text, optimizes it, and generates an object program Device, wherein said optimization is Optimization based on deleting conditional branches in a loop And the compiler device is Loop detection means for detecting a loop including an index having an initial value of 1 and an increment value of 1, and a conditional branch code existing in the loop detected by the loop detection means are detected. Is a comparison with a constant, and a condition branch code that satisfies the requirement that the dividend for division to calculate the remainder is an index of the loop and the division divisor is a positive integer constant is detected and the condition Branch detection means for recording information relating to the branch code, the number of unroll stages of the loop including the conditional branch code detected by the branch detection means, the divisor in the information recorded by the branch detection means, and the number of repetitions of the loop Unroll stage number determining means for determining a value smaller than the greatest common divisor and a divisor of the number of iterations of the loop, and the unroll stage number determining means In the process of unrolling the loop with the number of unroll stages determined in step (b) and expanding each code in the unrolling, information indicating the number of stages in which each code is expanded and the branch detection means From the recorded information, it is determined whether the conditional branch code condition detected by the branch detection means is “whether it is true / false” or “true or false”. A loop unrolling means for changing a conditional branch code whose condition is always true / false to an unconditional branch code, and unnecessary due to a change from the conditional branch code to the unconditional branch code by the loop unrolling means It can also be configured to have unnecessary code deleting means for deleting the lost code.
[0014]
In this case, a compiler that compiles the source program described in Fortran apparatus It is considered that it is one desirable form to apply to.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in detail with reference to the drawings.
[0016]
(1) First embodiment
FIG. 1 relates to a first embodiment of the present invention. Compiler device It is a block diagram which shows the structure of these.
[0017]
Referring to FIG. 1, according to the present embodiment Compiler device Is realized by the loop optimization unit 10 (a processing unit that optimizes the intermediate text 21 to generate the intermediate text 22) in the compiler (the intermediate text 21 and the intermediate text 22 are the compilers). apparatus Corresponds to the intermediate text generated in the process of interpreting the source program and optimizing it to generate the object program).
[0018]
The loop optimization unit 10 includes a loop detection unit 11, a branch detection unit 12, an unroll stage number determination unit 13, a loop unrolling unit 14, and an unnecessary code deletion unit 15.
[0019]
Each of these means generally operates as follows.
[0020]
The loop detection unit 11 detects a loop including an index (an index to be processed) having an initial value of 1 and an increment value of 1.
[0021]
The branch detection means 12 detects the conditional branch code existing in the loop detected by the loop detection means 11 and reads “the condition is a comparison between the result of the remainder and a constant, and the dividend to be used for calculating the remainder. Is the index of the loop, and the conditional branch code satisfying the requirement that the divisor of the division is a positive integer constant is detected, and information on the conditional branch code (initial value, final value, and increment value of the index) Record the divisor etc.).
[0022]
The unroll stage number determination means 13 determines the unroll stage number of the loop including the conditional branch code detected by the branch detection means 12 as the greatest promise between the divisor in the information recorded by the branch detection means 12 and the number of repetitions of the loop. Decide on a number value.
[0023]
The loop unrolling means 14 unrolls the loop with the number of unroll stages determined by the unroll stage number determining means 13, and the code in which each code is expanded in the process of expanding each code in the unrolling The condition of the conditional branch code detected by the branch detection means 12 from the information indicating whether or not and the information recorded by the branch detection means 12 are “whether true / false” or “true or false” Based on the determination, the conditional branch code whose condition is always true / false is changed to an unconditional branch code.
[0024]
Unnecessary code deletion means 15 is code that becomes unnecessary due to the change from the conditional branch code to the unconditional branch code by the loop unrolling means 14 (the unconditional branch code and the change are never executed due to the change. Code).
[0025]
FIG. 2 relates to the present embodiment. Compiler device It is a flowchart which shows the process of. This processing includes a loop search step 201, an in-loop processing target index presence / absence determination step 202, an in-loop conditional branch code search step 203, a condition content determination step 204, a remainder content determination step 205, a conditional branch code detection An information recording step 206, an unroll stage number determination step 207, a loop unrolling step 208, a conditional branch code unconditional branch code change step 209, and an unnecessary code deletion step 210.
[0026]
3 to 6 relate to the present embodiment. Compiler device It is a figure for demonstrating the specific operation | movement of.
[0027]
Next, with reference to FIG. 1 and FIG. 2, it concerns on this Embodiment comprised as mentioned above. Compiler device Will be described in detail.
[0028]
First, the loop detection means 11 in the loop optimization unit 10 searches for a loop from the intermediate text 21 (step 201 in FIG. 2), and the loop is an index to be processed (here, the initial value is 1). It is determined whether or not the increment value includes an index of 1 (step 202). Thereby, the loop detection unit 11 detects a loop including the index to be processed.
[0029]
Next, the branch detection unit 12 searches for a conditional branch code (code indicating a conditional branch instruction) existing in the loop (the loop including the index to be processed) detected by the loop detection unit 11 (step 203). It is determined whether or not the condition of the conditional branch code detected in step 203 is “comparison between remainder result and constant” (step 204), and if so (the condition is “remainder result and constant In the case of “comparison”, it is further determined whether or not the requirement “dividend dividend for calculating the remainder is an index of the loop and the division divisor is a positive integer constant” is satisfied. (Step 205).
[0030]
If it is determined in step 205 that “the requirement is satisfied”, the branch detection unit 12 detects a conditional branch code that satisfies the requirements of steps 204 and 205 described above, and information on the conditional branch code (the conditional branch) The value relating to the index of the loop including the code and the above divisor relating to the condition of the conditional branch code are recorded (step 206).
[0031]
Next, the unroll stage number determination unit 13 determines the unroll stage number of the loop including the conditional branch code detected by the branch detection unit 12 based on the information recorded by the branch detection unit 12 in Step 206 (Step 207). That is, the number of unroll stages is determined as the value of the greatest common divisor of the divisor in the information recorded in step 206 and the number of repetitions of the loop.
[0032]
The loop unrolling means 14 unrolls the loop with the number of unroll stages determined by the unroll stage number determining means 13 in step 207 (step 208).
[0033]
Further, the loop unrolling means 14 performs the processing shown in the following ac when unrolling in Step 208, and executes the conditional branch code (conditional branch detected by the branch detecting means 12) after unrolling. Code) is changed to an unconditional branch code (step 209).
[0034]
a. Information indicating in which stage each code is expanded in the process of expanding each code (information indicating which code group belongs to the number of unrolled stages) To get.
[0035]
b. Based on the information acquired in step a and the information recorded by the branch detection means 12 in step 206, the condition of the conditional branch code after unrolling is “whether true / false (always true or always false)”. And “whether it will be true or false”.
[0036]
c. Conditional branch code that is judged as “condition is always true / false” in b above is replaced with unconditional branch code (“code indicating that condition is always true and branch unconditionally”) or “condition is always false. And a process for changing to “a code indicating unconditional branching”).
[0037]
Finally, the unnecessary code deletion means 15 uses the code that has become unnecessary due to the change from the branch condition code to the unconditional branch code by the loop unrolling means 14 (from the unconditional branch code after the change and the “branch condition code The code relating to the operation instruction or the like that has never been executed due to “change to unconditional branch code” is deleted (step 210).
[0038]
Thereby, the intermediate text 22 that has been optimized based on the deletion of the conditional branch in the loop is output.
[0039]
If “NO” is determined in step 202, step 204, and step 205, the process ends at that point.
[0040]
Next, according to this embodiment Compiler device The specific operation will be described in detail with reference to FIGS. 1, 2, 3, 4, 5, and 6.
[0041]
Here, a specific example will be described in which optimization of the intermediate text 21 having the Fortran program piece (a program piece including a do loop with an initial value of index i of 1 and an increment value of 1) shown in FIG. 3 is performed.
[0042]
The loop detecting means 11 searches the intermediate text 21 and detects the do loop indicated by D in FIG. 3 (step 201 in FIG. 2).
[0043]
Furthermore, the loop detection unit 11 determines whether or not the do loop includes an index to be processed (an index having an initial value and an increment value of 1) (step 202). In the case of the Fortran program fragment shown in FIG. 3, since the initial value and increment value of the index i of the do loop of D are 1, “the do loop includes the index to be processed, that is, the optimization condition Is satisfied ”.
[0044]
The branch detection means 12 examines each code in the do loop and searches for a conditional branch code (step 203). In the case of FIG. 3, “if (mod (i, 4) .eq.0)” of A, “if (j.le.500)” of B, and “if (mod (i, 3) of C” ) .Ge.j) ”is detected as a conditional branch code.
[0045]
Next, the branch detection means 12 checks whether or not the condition (conditional expression) of the conditional branch code detected above is a comparison between the remainder result and a constant (step 204). In the case of FIG. 3, it is determined that the conditional expression in the conditional branch codes of A and C is “comparison between the result of the function mod for calculating the remainder and a constant”, and the two conditional branch codes are extracted.
[0046]
Further, the branch detection unit 12 states that the conditional branch code extracted above is “the division dividend for calculating the remainder of the conditional expression is a loop index, and the division divisor is a positive integer constant”. It is determined whether or not the requirement is satisfied (step 205). Then, a conditional branch code that satisfies this determination requirement is selected, and information (a value related to the index, the divisor, etc.) relating to the loop including the conditional branch code is recorded (step 206). In the case of FIG. 3, the conditional branch code of A is selected as the conditional branch code that satisfies the above requirements. Also, the initial value 1, the final value 1000, and the increment value 1 of the index i of the do loop (D in FIG. 3) including the conditional branch code, and the divisor 4 regarding the condition of the conditional branch code are recorded. To do.
[0047]
The unroll stage number determining means 13 determines the unroll stage number of the do loop based on the information recorded above (step 207). In the case of FIG. 3, since the divisor of the function mod for calculating the remainder in the conditional branch code of A is 4, and the number of repetitions of the do loop is 1000, the number of unroll stages is 4 (the greatest common divisor of 4 and 1000). ).
[0048]
The loop unrolling means 14 unrolls the do loop (step 208). As a result of this unrolling, the program piece shown in FIG. 3 is changed (deployed) like the program piece shown in FIG.
[0049]
Here, the loop unrolling means 14 records information indicating the number of levels of the expanded codes when the unrolling is performed. Then, based on this information and the information recorded in step 206, the conditional branch code whose condition is always true / false is changed to an unconditional branch code (step 209). In the case of FIG. 4, since the initial value of the index i of the do loop is 1 and the divisor of the function mod for calculating the remainder is 4, the expanded fourth (fourth stage) portion (code group) The condition “mod (i + 3,4) .eq.0” of the conditional branch code (D in FIG. 4) included in is always true, and the conditional branch code (in FIG. The conditions of A, B, and C) are always false. Therefore, based on the above, the conditional branch codes of A, B, C, and D in FIG. 4 are replaced with the unconditional branch codes of E, F, and G (“if (.false.)”) In FIG. And the unconditional branch code of H (“if (.true.)”).
[0050]
Finally, the unnecessary code deletion means 15 deletes the code changed to the unconditional branch code and the code that has never been executed due to the change (step 210). In the case of FIG. 5, since the conditions of E, F, and G of the unconditional branch code are “.false.” (Conditions that must be false), E, F, and G of the unconditional branch code, The codes I, J, and K that are never executed due to them are deleted as unnecessary codes. For H of the unconditional branch code, since the condition is “.true.” (A condition that is always true), only H of the unconditional branch code is deleted. The result of deleting unnecessary codes from the program piece of FIG. 5 is the program piece shown in FIG.
[0051]
As a result of the above optimization (optimization by deleting conditional branches in the loop), the conditional branch code that exists in the loop is deleted, so the remainder operation instruction that is the conditional expression of the conditional branch instruction is also deleted. The number of instructions executed in the is reduced. In general, since a branch instruction becomes a factor that hinders optimization, the effect of other optimization can be expected by reducing the number of conditional branch instructions (conditional branch codes).
[0052]
(2) Second embodiment
FIG. 1 relates to a second embodiment of the present invention. Compiler device It is also a block diagram which shows the structure. That is, according to this embodiment Compiler equipment This is realized by the loop optimization unit 10 (a processing unit that optimizes the intermediate text 21 to generate the intermediate text 22). The loop optimization unit 10 includes a loop detection unit 11, a branch detection unit 12, an unroll stage number determination unit 13, a loop unrolling unit 14, and an unnecessary code deletion unit 15.
[0053]
In the present embodiment, each of these means generally operates as follows.
[0054]
The loop detection means 11 detects a loop including an index whose initial value is a variable (including a constant other than 1) and whose increment value is 1.
[0055]
The branch detection means 12 detects the conditional branch code existing in the loop detected by the loop detection means 11 and reads “the condition is a comparison between the result of the remainder and a constant, and the dividend to be used for calculating the remainder. Is the index of the loop, and the conditional branch code satisfying the requirement that the divisor of the division is a positive integer constant is detected, and information on the conditional branch code (initial value, final value, and increment value of the index) Record the divisor etc.).
[0056]
The unroll stage number determination unit 13 determines the unroll stage number of the loop including the conditional branch code detected by the branch detection unit 12 as the divisor value in the information recorded by the branch detection unit 12.
[0057]
The loop unrolling means 14 is an unrolled code group (a code group to be unrolled when the number of loop repetitions is adjusted to be as large as possible by a multiple of the unrolled stage number determined by the unrolled stage number determining means 13. Is generated in the previous stage of the code group to be unrolled, and then the loop is unrolled with the number of unroll stages determined by the unroll stage number determining means 13. In addition, in the process of developing each code in the unrolling, the branch detection unit 12 detects from the information indicating how many stages the code is expanded and the information recorded by the branch detection unit 12. Judgment is made on whether the conditional branch code is “true / false” or “true or false”, and the conditional branch is always true / false based on the determination Change the code to unconditional branch code.
[0058]
Unnecessary code deletion means 15 is code that becomes unnecessary due to the change from the conditional branch code to the unconditional branch code by the loop unrolling means 14 (the unconditional branch code and the change are never executed due to the change. Code).
[0059]
7 and 8 are related to this embodiment. Compiler device It is a figure for demonstrating the specific operation | movement of.
[0060]
According to the first embodiment Compiler device In the loop detection means 11, a loop including an index having an initial value of 1 and an increment value of 1 is targeted for optimization. On the other hand, according to the second embodiment Compiler device Thus, even if the initial value of the loop index is a variable or a constant other than 1, the loop can be targeted for optimization.
[0061]
Next, according to this embodiment Compiler device The specific operation will be described with reference to FIGS.
[0062]
Here, a specific example will be described in which optimization of the intermediate text 21 having the Fortran program fragment (a program fragment including a do loop whose initial value of index i is variable k and increment value is 1) shown in FIG. 7 is performed. .
[0063]
In the Fortran program fragment of FIG. 7, the initial value of the index i of the do loop is set by A in FIG. 7, but the initial value is a variable k and not a constant of 1. Therefore, the index extraction condition (requirement corresponding to “index to be processed” in the determination of step 202 in FIG. 2) of the loop detection unit 11 in the first embodiment is not satisfied. However, the loop detecting means 11 in the present embodiment can also optimize a loop including such an index.
[0064]
Further, the unroll stage number determining means 13 has a divisor of a function mod for obtaining a remainder in the conditional expression of the conditional branch code of B in FIG. , 4 unroll stages When decide.
[0065]
Loop unrolling means 14 is a group of unrolled cords (A code group divided as a code group other than the code group to be unrolled when the loop repetition number is adjusted to be as large as possible by a multiple of the unroll stage number determined by the unroll stage number determining means 13) Is generated before the code group to be unrolled After that, the loop is unrolled with the number of stages determined by the unroll stage number determining means 13. . When the portion C in FIG. 8 is such that the number of repetitions of the do loop in the unroll target code group (portion D in FIG. 8) is a multiple of four of the above divisor (the number of unroll steps is four). Code group that is not subject to unrolling. Here, “iand” is one of functions related to bit operations in Fortran, and is a function for obtaining the logical product of each bit. Further, “max” is a function for obtaining the maximum value in Fortran.
[0066]
In this case, the loop unrolling means 14 can determine that the conditional branch code existing in the portion D in FIG. 8 is always true / false as in the first embodiment. On the other hand, it is possible to apply the same unrolling and “change from a conditional branch code to an unconditional branch code” as in the first embodiment.
[0067]
Then, the unnecessary code deleting unit 15 deletes the unnecessary code in the portion, and generates the intermediate text 22 having the Fortran program piece as shown in FIG.
[0068]
In this way, in this embodiment as well, in the same way as in the first embodiment, the number of instructions to be executed can be reduced (see FIG. 8). Compiler device The execution performance of the object program generated by this is improved.
[0069]
(3) Third embodiment
FIG. 1 relates to a third embodiment of the present invention. Compiler device It is also a block diagram which shows the structure. That is, according to this embodiment Compiler equipment This is realized by the loop optimization unit 10 (a processing unit that optimizes the intermediate text 21 to generate the intermediate text 22). The loop optimization unit 10 includes a loop detection unit 11, a branch detection unit 12, an unroll stage number determination unit 13, a loop unrolling unit 14, and an unnecessary code deletion unit 15.
[0070]
In the present embodiment, each of these means generally operates as follows.
[0071]
The loop detection means 11 detects a loop including an index whose initial value is 1 and whose increment value is a constant.
[0072]
The branch detection means 12 detects the conditional branch code existing in the loop detected by the loop detection means 11 and reads “the condition is a comparison between the result of the remainder and a constant, and the dividend to be used for calculating the remainder. Is the index of the loop, and the conditional branch code satisfying the requirement that the divisor of the division is a positive integer constant is detected, and information on the conditional branch code (initial value, final value, and increment value of the index) Record the divisor etc.).
[0073]
The unroll stage number determination means 13 determines the unroll stage number of the loop including the conditional branch code detected by the branch detection means 12 based on the information recorded by the branch detection means 12 as “the increment value after deformation is the increment before deformation”. It is determined so as to be the value of the greatest common divisor of the value satisfying the requirement of “the least common multiple of the value and the divisor” and the number of repetitions of the loop.
[0074]
The loop unrolling means 14 unrolls the loop with the number of unroll stages determined by the unroll stage number determining means 13, and the code in which each code is expanded in the process of expanding each code in the unrolling The condition of the conditional branch code detected by the branch detection means 12 from the information indicating whether or not and the information recorded by the branch detection means 12 are “whether true / false” or “true or false” Based on the determination, the conditional branch code whose condition is always true / false is changed to an unconditional branch code.
[0075]
Unnecessary code deletion means 15 is code that becomes unnecessary due to the change from the conditional branch code to the unconditional branch code by the loop unrolling means 14 (the unconditional branch code and the change are never executed due to the change. Code).
[0076]
9 and 10 are related to the present embodiment. Compiler device It is a figure for demonstrating the specific operation | movement of.
[0077]
According to the first embodiment Compiler device Then, in the loop detection means 11, the loop whose index increment value is 1 is targeted for optimization. On the other hand, according to the third embodiment Compiler device Then, a loop whose index increment value is not 1 can also be targeted for optimization.
[0078]
Next, according to this embodiment Compiler device The specific operation will be described with reference to FIGS. 9 and 10. FIG.
[0079]
Here, a specific example in the case where optimization of the intermediate text 21 having the Fortran program fragment (a program fragment including a do loop having an initial value of index i of 1 and an increment value of 6) shown in FIG. 9 will be described.
[0080]
In the Fortran program fragment of FIG. 9, the increment value of the index i of the do loop is set to 6 at A in FIG. Therefore, the index extraction condition (condition regarding the increment value) of the loop detection unit 11 in the first embodiment is not satisfied. However, since the loop detection unit 11 according to the present embodiment has no restriction on the index extraction condition regarding such an increment value, a loop including such an index can also be targeted for optimization.
[0081]
At this time, the unroll stage number determining means 13 unrolls so that the increment value after deformation becomes 12 which is the least common multiple of the increment value 6 before deformation and the divisor 4 of the function mod for calculating the remainder of B in FIG. Determine the number of steps.
[0082]
Then, the loop unrolling means 14 performs deformation (development) of the do loop in FIG. 9 by performing unrolling with twelve unrolling stages. Compiler device Can be applied.
[0083]
In other words, the unnecessary code deletion unit 15 performs unrolling by the loop unrolling unit 14 and “change from the conditional branch code to the unconditional branch code”, deletes the unnecessary code, and performs the Fortran as shown in FIG. An intermediate text 22 having a program piece is generated.
[0084]
Also in the present embodiment, since the instruction executed in the loop is deleted by application of the present invention (see FIG. 10), the present embodiment relates to this embodiment. Compiler device This improves the execution performance of the object program generated by.
[0085]
(4) Fourth embodiment
FIG. 1 relates to a fourth embodiment of the present invention. Compiler device It is also a block diagram which shows the structure. That is, according to this embodiment Compiler equipment This is realized by the loop optimization unit 10 (a processing unit that optimizes the intermediate text 21 to generate the intermediate text 22). The loop optimization unit 10 includes a loop detection unit 11, a branch detection unit 12, an unroll stage number determination unit 13, a loop unrolling unit 14, and an unnecessary code deletion unit 15.
[0086]
In the present embodiment, each of these means generally operates as follows.
[0087]
The loop detection means 11 detects a loop including an index having an initial value of 1 and an increment value of 1.
[0088]
The branch detection means 12 detects the conditional branch code existing in the loop detected by the loop detection means 11 and reads “the condition is a comparison between the result of the remainder and a constant, and the dividend to be used for calculating the remainder. Is the index of the loop, and the conditional branch code satisfying the requirement that the divisor of the division is a positive integer constant is detected, and information on the conditional branch code (initial value, final value, and increment value of the index) Record the divisor etc.).
[0089]
The unroll stage number determination means 13 determines the unroll stage number of the loop including the conditional branch code detected by the branch detection means 12 as the greatest promise between the divisor in the information recorded by the branch detection means 12 and the number of repetitions of the loop. The value is smaller than the number and is a divisor of the number of iterations of the loop.
[0090]
The loop unrolling means 14 unrolls the loop with the number of unroll stages determined by the unroll stage number determining means 13, and the code in which each code is expanded in the process of expanding each code in the unrolling The condition of the conditional branch code detected by the branch detection means 12 from the information indicating whether or not and the information recorded by the branch detection means 12 are “whether true / false” or “true or false” Based on the determination, the conditional branch code whose condition is always true / false is changed to an unconditional branch code.
[0091]
Unnecessary code deletion means 15 is code that becomes unnecessary due to the change from the conditional branch code to the unconditional branch code by the loop unrolling means 14 (the unconditional branch code and the change are never executed due to the change. Code).
[0092]
11 and 12 are related to the present embodiment. Compiler device It is a figure for demonstrating the specific operation | movement of.
[0093]
According to the first embodiment Compiler device In this case, the number of unrolled stages is the value of the greatest common divisor of the divisor relating to the remainder in the conditional branch code and the number of repetitions of the loop. In contrast, according to the fourth embodiment Compiler device Does not limit the number of unroll stages to the above value, but “a value smaller than the greatest common divisor of the divisor and the number of iterations of the loop and a divisor of the number of iterations of the loop” The number of unroll stages is determined so as to be (another value that enables the conditional branch code to be deleted). Thereby, even if the divisor is a large value, the idea of the present invention can be applied without increasing the code group after unrolling.
[0094]
Next, according to this embodiment Compiler device The specific operation will be described with reference to FIGS. 11 and 12. FIG.
[0095]
Here, the Fortran program fragment shown in FIG. 11 (a do loop having a conditional branch code whose divisor relating to the remainder in the condition is 1000 and a large value (the initial value of the index i is 1, the increment value is 1 and the number of repetitions is 1000000) A specific example in the case where optimization of the intermediate text 21 having the program fragment including the do loop) is performed will be described.
[0096]
In the Fortran program fragment of FIG. 11, the divisor of the function mod for calculating the remainder is 1000, and according to the first embodiment Compiler device If this processing is applied, the code group after unrolling becomes very large.
[0097]
In contrast, according to the present embodiment Compiler device As shown in FIG. 12, unrolling can be performed with an appropriate number of unroll stages of 4, which is a divisor of 1000000 of the number of repetitions of the do loop, and the concept of the present invention can be applied.
[0098]
According to this embodiment Compiler device As a result of the application, all conditional branch codes detected by the branch detection means 12 cannot be deleted after unrolling, but three conditional branch codes in the do loop can be deleted (FIG. 12). See), according to this embodiment Compiler device The execution performance of the object program generated by this is improved.
[0099]
(5) Other embodiments
Of the present invention Compiler device Then, in addition to the first to fourth embodiments described above, the following embodiments a to d are also conceivable. It should be noted that according to these embodiments Compiler device The configuration can also be shown by the block diagram shown in FIG.
[0100]
a. The fifth embodiment can be realized by combining the idea of the second embodiment and the idea of the third embodiment. According to this embodiment Compiler device The configuration includes each means as described below.
[0101]
The loop detection means 11 detects a loop including an index whose initial value is a variable and whose increment value is a constant.
[0102]
The branch detection means 12 detects the conditional branch code existing in the loop detected by the loop detection means 11 and reads “the condition is a comparison between the result of the remainder and a constant, and the dividend to be used for calculating the remainder. Is the index of the loop, and the conditional branch code satisfying the requirement that the divisor of the division is a positive integer constant is detected, and information regarding the conditional branch code is recorded.
[0103]
The unroll stage number determination means 13 determines the unroll stage number of the loop including the conditional branch code detected by the branch detection means 12 based on the information recorded by the branch detection means 12 as “the incremental value after deformation is the incremental value before deformation. It is determined to be a value that satisfies the requirement of “the least common multiple with the divisor”.
[0104]
The loop unrolling means 14 generates a non-unroll target code group in the previous stage of the unroll target code group, and then unrolls the loop with the number of unroll stages determined by the unroll stage number determination means 13. The condition of the conditional branch code detected by the branch detecting means 12 from the information indicating how many stages the code is developed in the process of developing each code and the information recorded by the branch detecting means 12 Judgment on whether or not it will always be true / false and whether it will be true or false, and based on that determination, conditional branch code that makes the condition true / false will be unconditional branch code change.
[0105]
The unnecessary code deleting unit 15 deletes a code that has become unnecessary due to the change from the conditional branch code to the unconditional branch code by the loop unrolling unit 14.
[0106]
b. The sixth embodiment can be realized by combining the idea of the second embodiment and the idea of the fourth embodiment. According to this embodiment Compiler device The configuration includes each means as described below.
[0107]
The loop detection means 11 detects a loop including an index whose initial value is a variable and whose increment value is 1.
[0108]
The branch detection means 12 detects the conditional branch code existing in the loop detected by the loop detection means 11 and reads “the condition is a comparison between the result of the remainder and a constant, and the dividend to be used for calculating the remainder. Is the index of the loop, and the conditional branch code satisfying the requirement that the divisor of the division is a positive integer constant is detected, and information regarding the conditional branch code is recorded.
[0109]
The unroll stage number determining means 13 is such that the unroll stage number of the loop including the conditional branch code detected by the branch detection means 12 is smaller than the divisor in the information recorded by the branch detection means 12, and the number of repetitions of the loop. Determine a value that is a divisor of.
[0110]
The loop unrolling means 14 generates a code group that is not to be unrolled before the code group to be unrolled, and then performs unrolling of the loop with the number of unroll stages determined by the unroll stage number determining means. Regarding the condition of the conditional branch code detected by the branch detection means 12 from the information indicating how many stages the code is developed in the process of developing the code and the information recorded by the branch detection means 12 Judgment whether "becomes true / false" or "whether true or false" is made, and based on this judgment, the conditional branch code whose condition is always true / false is changed to unconditional branch code To do.
[0111]
The unnecessary code deleting unit 15 deletes a code that has become unnecessary due to the change from the conditional branch code to the unconditional branch code by the loop unrolling unit 14.
[0112]
c. The seventh embodiment can be realized by combining the idea of the third embodiment and the idea of the fourth embodiment. According to this embodiment Compiler device The configuration includes each means as described below.
[0113]
The loop detection means 11 detects a loop including an index whose initial value is 1 and whose increment value is a constant.
[0114]
The branch detection means 12 detects the conditional branch code existing in the loop detected by the loop detection means 11 and reads “the condition is a comparison between the result of the remainder and a constant, and the dividend to be used for calculating the remainder. Is the index of the loop, and the conditional branch code satisfying the requirement that the divisor of the division is a positive integer constant is detected, and information regarding the conditional branch code is recorded.
[0115]
The unroll stage number determination means 13 determines the unroll stage number of the loop including the conditional branch code detected by the branch detection means 12 based on the information recorded by the branch detection means 12 as “the increment value after deformation is the increment value before deformation”. The value is smaller than the greatest common divisor of the value satisfying the requirement of “the least common multiple with the divisor” and the number of iterations of the loop, and a value that is a divisor of the number of iterations of the loop.
[0116]
The loop unrolling means 14 unrolls the loop with the number of unroll stages determined by the unroll stage number determining means 13, and the code in which each code is expanded in the process of expanding each code in the unrolling The condition of the conditional branch code detected by the branch detection means 12 from the information indicating whether or not and the information recorded by the branch detection means 12 are “whether true / false” or “true or false” Based on the determination, the conditional branch code whose condition is always true / false is changed to an unconditional branch code.
[0117]
The unnecessary code deleting unit 15 deletes a code that has become unnecessary due to the change from the conditional branch code to the unconditional branch code by the loop unrolling unit 14.
[0118]
d. The eighth embodiment can be realized by combining the idea of the second embodiment, the idea of the third embodiment, and the idea of the fourth embodiment. According to this embodiment Compiler device The configuration includes each means as described below.
[0119]
The loop detection means 11 detects a loop including an index whose initial value is a variable and whose increment value is a constant.
[0120]
The branch detection means 12 detects the conditional branch code existing in the loop detected by the loop detection means 11 and reads “the condition is a comparison between the result of the remainder and a constant, and the dividend to be used for calculating the remainder. Is the index of the loop, and the conditional branch code satisfying the requirement that the divisor of the division is a positive integer constant is detected, and information regarding the conditional branch code is recorded.
[0121]
The unroll stage number determination means 13 determines the unroll stage number of the loop including the conditional branch code detected by the branch detection means 12 based on the information recorded by the branch detection means 12 as “the incremental value after deformation is the incremental value before deformation. The value is smaller than a value satisfying the requirement of “the least common multiple with the divisor” and is a divisor of the number of iterations of the loop.
[0122]
The loop unrolling means 14 generates a non-unroll target code group in the previous stage of the unroll target code group, and then unrolls the loop with the number of unroll stages determined by the unroll stage number determination means 13. The condition of the conditional branch code detected by the branch detecting means 12 from the information indicating how many stages the code is developed in the process of developing each code and the information recorded by the branch detecting means 12 Judgment on whether or not it will always be true / false and whether it will be true or false, and based on this determination, conditional branch code whose condition is always true / false will be unconditional branch code change.
[0123]
The unnecessary code deleting unit 15 deletes a code that has become unnecessary due to the change from the conditional branch code to the unconditional branch code by the loop unrolling unit 14.
[0124]
(6) Ninth embodiment
FIG. 13 relates to a ninth embodiment of the present invention. Compiler device It is a block diagram which shows the structure of these.
[0125]
Referring to FIG. 13, according to the ninth embodiment of the present invention. Compiler device Are related to the first to eighth embodiments shown in FIG. Compiler device Against Contains compiler The recording medium 100 is different. The recording medium 100 may be a magnetic disk, a semiconductor memory, or other recording medium.
[0126]
compiler Loop optimization unit 10 (optimizing intermediate text 21 to generate intermediate text 22 from recording medium 100, loop detection means 11, branch detection means 12, unroll stage number determination means 13, loop unrolling means 14, and unnecessary The data is read into a computer that implements a loop optimizing unit 10) including a code deleting unit 15, and the operation of the loop optimizing unit 10 is controlled by a loop detecting unit 11, a branch detecting unit 12, an unroll stage number determining unit 13, and a loop unrolling unit 14. , And unnecessary code deletion means 15. compiler The operations of the loop detection means 11, the branch detection means 12, the unroll stage number determination means 13, the loop unrolling means 14 and the unnecessary code deletion means 15 under the control of the loop detection means 11 in the first to eighth embodiments are as follows. , Branch detection means 12, unroll stage number determination means 13, loop unrolling means 14, and unnecessary code deletion means 15 are exactly the same, and will not be described in detail.
[0127]
【The invention's effect】
As described above, according to the present invention, a compiler capable of generating an object program with a short execution time apparatus Can be realized (optimization for shortening the execution time can be realized with certainty).
[0128]
The reason why such an effect occurs is that there is no need to generate a branch instruction for determining whether to execute an expression executed only under a specific condition in a loop as in the prior art, This is because it is possible to perform other optimizations that could not be performed conventionally. In addition, the conditional branch (conditional branch code) existing in the loop is changed to an unconditional branch (unconditional branch code) by unrolling the loop, and unnecessary code (conditional branch code and This is because, for example, a code for an operation instruction associated therewith can be appropriately deleted, and an instruction that has always been executed in a loop in the prior art is not executed.
[Brief description of the drawings]
FIG. 1 relates to first to eighth embodiments of the present invention. Compiler device It is a block diagram which shows the structure of these.
FIG. 2 relates to a first embodiment of the present invention. Compiler device It is a flowchart which shows the process of.
FIG. 3 relates to a first embodiment of the present invention. Compiler device FIG. 3 is a diagram for explaining a specific operation of (Fortran program fragment in intermediate text to be optimized).
FIG. 4 relates to a first embodiment of the present invention. Compiler device FIG. 6 is a diagram for explaining a specific operation of (Fortran program fragment after application of unrolling).
FIG. 5 relates to a first embodiment of the present invention. Compiler device FIG. 8 is a diagram for explaining a specific operation of (Fortran program fragment after applying a change from a conditional branch code to an unconditional branch code).
FIG. 6 is related to the first embodiment of the present invention. Compiler device FIG. 6 is a diagram for explaining a specific operation of (a diagram showing the Fortran program fragment after application of optimization).
FIG. 7 is a diagram according to a second embodiment of the present invention. Compiler device FIG. 3 is a diagram for explaining a specific operation of (Fortran program fragment in intermediate text to be optimized).
FIG. 8 relates to a second embodiment of the present invention Compiler device FIG. 6 is a diagram for explaining a specific operation of (a diagram showing the Fortran program fragment after application of optimization).
FIG. 9 relates to a third embodiment of the present invention. Compiler device FIG. 3 is a diagram for explaining a specific operation of (Fortran program fragment in intermediate text to be optimized).
FIG. 10 relates to a third embodiment of the present invention. Compiler device FIG. 6 is a diagram for explaining a specific operation of (a diagram showing the Fortran program fragment after application of optimization).
FIG. 11 relates to a fourth embodiment of the present invention. Compiler device FIG. 3 is a diagram for explaining a specific operation of (Fortran program fragment in intermediate text to be optimized).
FIG. 12 relates to a fourth embodiment of the present invention. Compiler device FIG. 6 is a diagram for explaining a specific operation of (a diagram showing the Fortran program fragment after application of optimization).
FIG. 13 relates to a ninth embodiment of the present invention. Compiler device It is a block diagram which shows the structure of these.
[Explanation of symbols]
10 Loop optimization section
11 Loop detection means
12 Branch detection means
13 Unroll stage number determining means
14 Loop unrolling means
15 Unnecessary code deletion means
21, 22 Intermediate text
100 recording media

Claims (13)

A compiler device that interprets a source program, generates intermediate text, performs optimization, and generates an object program , wherein the optimization is optimization based on the deletion of conditional branches in a loop , and the compiler device
Loop detection means for detecting a loop including an index having an initial value of 1 and an increment value of 1;
The conditional branch code present in the loop detected by the loop detection means is detected, and “the condition is a comparison between the result of the remainder and a constant, and the dividend of the division for calculating the remainder is the index of the loop. Branch detecting means for detecting a conditional branch code that satisfies the requirement that `` the divisor of the division is a positive integer constant '' and recording information on the conditional branch code;
Unroll stage number for determining the unroll stage number of the loop including the conditional branch code detected by the branch detection means as the value of the greatest common divisor between the divisor in the information recorded by the branch detection means and the repetition number of the loop. A determination means;
Information indicating the number of stages in which each code is unrolled in the process of unrolling the loop with the number of unroll stages determined by the unroll stage number determining means and expanding each code in the unrolling From the information recorded by the branch detector, it is determined whether the condition of the conditional branch code detected by the branch detector is “true / false” or “true” or “false” And a loop unrolling means for changing a conditional branch code whose condition is always true / false based on the determination to an unconditional branch code,
A compiler apparatus comprising: unnecessary code deletion means for deleting code that is no longer necessary due to a change from a conditional branch code to an unconditional branch code by the loop unrolling means. A compiler device that interprets a source program, generates intermediate text, performs optimization, and generates an object program , wherein the optimization is optimization based on the deletion of conditional branches in a loop , and the compiler device
Loop detection means for detecting a loop including an index whose initial value is a variable and whose increment value is 1,
The conditional branch code present in the loop detected by the loop detection means is detected, and “the condition is a comparison between the result of the remainder and a constant, and the dividend of the division for calculating the remainder is the index of the loop. Branch detecting means for detecting a conditional branch code that satisfies the requirement that `` the divisor of the division is a positive integer constant '' and recording information on the conditional branch code;
Unroll stage number determination means for determining the unroll stage number of the loop including the conditional branch code detected by the branch detection means as the value of the divisor in the information recorded by the branch detection means;
In the process of unrolling the unrolled code group before the unrolled code group, unrolling the loop with the unrolled stage number determined by the unrolled stage number determining means, and developing each code in the unrolling The condition of the conditional branch code detected by the branch detection means is determined to be “true / false” from the information indicating the number of stages in which each code is expanded and the information recorded by the branch detection means. Loop unrolling means for determining whether or not to become true or false and changing a conditional branch code whose condition is always true / false based on the determination to an unconditional branch code ,
A compiler apparatus comprising: unnecessary code deletion means for deleting code that is no longer necessary due to a change from a conditional branch code to an unconditional branch code by the loop unrolling means. A compiler device that interprets a source program, generates intermediate text, performs optimization, and generates an object program , wherein the optimization is optimization based on the deletion of conditional branches in a loop , and the compiler device
Loop detection means for detecting a loop including an index having an initial value of 1 and an increment value of a constant;
The conditional branch code present in the loop detected by the loop detection means is detected, and “the condition is a comparison between the result of the remainder and a constant, and the dividend of the division for calculating the remainder is the index of the loop. Branch detecting means for detecting a conditional branch code that satisfies the requirement that `` the divisor of the division is a positive integer constant '' and recording information on the conditional branch code;
Based on the information recorded by the branch detection unit, the number of unroll stages of the loop including the conditional branch code detected by the branch detection unit is calculated as follows: "Increment value after unroll processing is the increment value before unroll processing and the above divisor. An unroll stage number determining means for determining a value that satisfies the requirement of `` to be the least common multiple '' by dividing the value by the incremental value before the unroll process ;
Information indicating the number of stages in which each code is unrolled in the process of unrolling the loop with the number of unroll stages determined by the unroll stage number determining means and expanding each code in the unrolling From the information recorded by the branch detector, it is determined whether the condition of the conditional branch code detected by the branch detector is “true / false” or “true” or “false” And a loop unrolling means for changing a conditional branch code whose condition is always true / false based on the determination to an unconditional branch code,
A compiler apparatus comprising: unnecessary code deletion means for deleting code that is no longer necessary due to a change from a conditional branch code to an unconditional branch code by the loop unrolling means. A compiler device that interprets a source program, generates intermediate text, performs optimization, and generates an object program , wherein the optimization is optimization based on the deletion of conditional branches in a loop , and the compiler device
Loop detection means for detecting a loop including an index having an initial value of 1 and an increment value of 1;
The conditional branch code present in the loop detected by the loop detection means is detected, and “the condition is a comparison between the result of the remainder and a constant, and the dividend of the division for calculating the remainder is the index of the loop. Branch detecting means for detecting a conditional branch code that satisfies the requirement that `` the divisor of the division is a positive integer constant '' and recording information on the conditional branch code;
The unrolled stage number of the loop including the conditional branch code detected by the branch detection unit is a value smaller than the greatest common divisor of the divisor and the loop repetition number in the information recorded by the branch detection unit, and Unroll stage number determining means for determining a value that is a divisor of the number of loop iterations;
Information indicating the number of stages in which each code is unrolled in the process of unrolling the loop with the number of unroll stages determined by the unroll stage number determining means and expanding each code in the unrolling From the information recorded by the branch detector, it is determined whether the condition of the conditional branch code detected by the branch detector is “true / false” or “true” or “false” And a loop unrolling means for changing a conditional branch code whose condition is always true / false based on the determination to an unconditional branch code,
A compiler apparatus comprising: unnecessary code deletion means for deleting code that is no longer necessary due to a change from a conditional branch code to an unconditional branch code by the loop unrolling means. A compiler device that interprets a source program, generates intermediate text, performs optimization, and generates an object program , wherein the optimization is optimization based on the deletion of conditional branches in a loop , and the compiler device
Loop detection means for detecting a loop including an index whose initial value is a variable and whose increment value is a constant;
The conditional branch code present in the loop detected by the loop detection means is detected, and “the condition is a comparison between the result of the remainder and a constant, and the dividend of the division for calculating the remainder is the index of the loop. Branch detecting means for detecting a conditional branch code that satisfies the requirement that `` the divisor of the division is a positive integer constant '' and recording information on the conditional branch code;
Based on the information unrolling number of loops have been recorded in the branch detection means including conditional branch code the detected by the branch detection unit "increment after unrolling process before unrolling processing increment and between the divisor An unroll stage number determining means for determining a value satisfying the requirement of “the least common multiple”;
In the process of unrolling the unrolled code group before the unrolled code group, unrolling the loop with the unrolled stage number determined by the unrolled stage number determining means, and developing each code in the unrolling The condition of the conditional branch code detected by the branch detection means is determined to be “true / false” from the information indicating the number of stages in which each code is expanded and the information recorded by the branch detection means. Loop unrolling means for determining whether or not to become true or false and changing a conditional branch code whose condition is always true / false based on the determination to an unconditional branch code ,
A compiler apparatus comprising: unnecessary code deletion means for deleting code that is no longer necessary due to a change from a conditional branch code to an unconditional branch code by the loop unrolling means. A compiler device that interprets a source program, generates intermediate text, performs optimization, and generates an object program , wherein the optimization is optimization based on the deletion of conditional branches in a loop , and the compiler device
Loop detection means for detecting a loop including an index whose initial value is a variable and whose increment value is 1,
The conditional branch code present in the loop detected by the loop detection means is detected, and “the condition is a comparison between the result of the remainder and a constant, and the dividend of the division for calculating the remainder is the index of the loop. Branch detecting means for detecting a conditional branch code that satisfies the requirement that `` the divisor of the division is a positive integer constant '' and recording information on the conditional branch code;
The number of unroll stages of the loop including the conditional branch code detected by the branch detection means is a value smaller than the divisor in the information recorded by the branch detection means and a divisor of the number of repetitions of the loop. Unrolling stage number determining means for determining;
In the process of unrolling the unrolled code group before the unrolled code group, unrolling the loop with the unrolled stage number determined by the unrolled stage number determining means, and developing each code in the unrolling The condition of the conditional branch code detected by the branch detection means is determined to be “true / false” from the information indicating the number of stages in which each code is expanded and the information recorded by the branch detection means. Loop unrolling means for determining whether or not to become true or false and changing a conditional branch code whose condition is always true / false based on the determination to an unconditional branch code ,
A compiler apparatus comprising: an unnecessary code deleting unit that deletes a code that has become unnecessary due to a change from a conditional branch code to an unconditional branch code by the loop unrolling unit. A compiler device that interprets a source program, generates intermediate text, performs optimization, and generates an object program , wherein the optimization is optimization based on the deletion of conditional branches in a loop , and the compiler device
Loop detection means for detecting a loop including an index having an initial value of 1 and an increment value of a constant;
The conditional branch code present in the loop detected by the loop detection means is detected, and “the condition is a comparison between the result of the remainder and a constant, and the dividend of the division for calculating the remainder is the index of the loop. Branch detecting means for detecting a conditional branch code that satisfies the requirement that `` the divisor of the division is a positive integer constant '' and recording information on the conditional branch code;
Based on the information unrolling number of loops have been recorded in the branch detection means including conditional branch code the detected by the branch detection unit "increment after unrolling process before unrolling processing increment and between the divisor An unroll stage number determining means that determines a value that is smaller than the greatest common divisor of a value that satisfies the requirement of `` being the least common multiple '' and the number of iterations of the loop and is a divisor of the number of iterations of the loop;
Information indicating the number of stages in which each code is unrolled in the process of unrolling the loop with the number of unroll stages determined by the unroll stage number determining means and expanding each code in the unrolling From the information recorded by the branch detector, it is determined whether the condition of the conditional branch code detected by the branch detector is “true / false” or “true” or “false” And a loop unrolling means for changing a conditional branch code whose condition is always true / false based on the determination to an unconditional branch code,
A compiler apparatus comprising: unnecessary code deletion means for deleting code that is no longer necessary due to a change from a conditional branch code to an unconditional branch code by the loop unrolling means. A compiler device that interprets a source program, generates intermediate text, performs optimization, and generates an object program , wherein the optimization is optimization based on the deletion of conditional branches in a loop , and the compiler device
Loop detection means for detecting a loop including an index whose initial value is a variable and whose increment value is a constant;
The conditional branch code present in the loop detected by the loop detection means is detected, and “the condition is a comparison between the result of the remainder and a constant, and the dividend of the division for calculating the remainder is the index of the loop. Branch detecting means for detecting a conditional branch code that satisfies the requirement that `` the divisor of the division is a positive integer constant '' and recording information on the conditional branch code;
Based on the information unrolling number of loops have been recorded in the branch detection means including conditional branch code the detected by the branch detection unit "increment after unrolling process before unrolling processing increment and between the divisor An unroll stage number determining means that determines a value that is smaller than a value that satisfies the requirement of `` being the least common multiple '' and that is a divisor of the number of iterations of the loop;
In the process of unrolling the unrolled code group before the unrolled code group, unrolling the loop with the unrolled stage number determined by the unrolled stage number determining means, and developing each code in the unrolling The condition of the conditional branch code detected by the branch detection means is determined to be “true / false” from the information indicating the number of stages in which each code is expanded and the information recorded by the branch detection means. Loop unrolling means for determining whether or not to become true or false and changing a conditional branch code whose condition is always true / false based on the determination to an unconditional branch code ,
A compiler apparatus comprising: unnecessary code deletion means for deleting code that is no longer necessary due to a change from a conditional branch code to an unconditional branch code by the loop unrolling means. The compiler apparatus according to claim 1, wherein the source program is a source program described in Fortran. A computer-readable recording medium storing a compiler that interprets a source program, generates intermediate text, and performs optimization to generate an object program , wherein the optimization is based on deletion of conditional branches in the loop The compiler detects a loop including an index having an initial value of 1 and an increment value of 1, and detects a conditional branch code existing in the loop detected by the loop detection unit; A conditional branch that satisfies the requirement that "the condition is a comparison between the result of the remainder and a constant, the dividend of the division for calculating the remainder is an index of the loop, and the divisor of the division is a positive integer constant" Branch detection means for detecting a code and recording information on the conditional branch code, conditional branch code detected by the branch detection means The unrolled stage number of the loop including the unrolled stage number determining means for determining the value of the greatest common divisor of the divisor in the information recorded by the branch detecting means and the number of repetitions of the loop, determined by the unrolled stage number determining means Information indicating the number of stages in which each code is expanded in the process of unrolling the loop with the number of unroll stages and expanding each code in the unrolling, and information recorded by the branch detection unit From the above, the condition of the conditional branch code detected by the branch detection means is determined to be “whether true / false” or “true or false”. Loop unrolling means for changing a conditional branch code that is always true / false to an unconditional branch code, and the loop unrolling means Conditional branch code from due to changes to the unconditional branch code is intended for causing a computer to function as dead code deleting means for deleting code that has become unnecessary, the computer-readable recording medium in which the compiler is stored. A computer-readable recording medium storing a compiler that interprets a source program, generates intermediate text, and performs optimization to generate an object program , wherein the optimization is based on deletion of conditional branches in the loop And the compiler detects a loop detecting means for detecting a loop including an index having an initial value of a variable and an increment value of 1, a conditional branch code existing in the loop detected by the loop detecting means, A conditional branch that satisfies the requirement that "the condition is a comparison between the result of the remainder and a constant, the dividend of the division for calculating the remainder is an index of the loop, and the divisor of the division is a positive integer constant" A branch detecting means for detecting a code and recording information on the conditional branch code, and a conditional branch code detected by the branch detecting means. An unroll stage number determining means for determining the unroll stage number of the loop including the unroll target code group for determining the value of the divisor in the information recorded by the branch detection means, and generating the unroll target code group in the previous stage of the unroll target code group, Information indicating the number of stages in which each code is unrolled in the process of unrolling the loop with the number of unroll stages determined by the unroll stage number determining means and expanding each code in the unrolling From the information recorded by the branch detector, it is determined whether the condition of the conditional branch code detected by the branch detector is “true / false” or “true” or “false” If it is a loop unrolling means to change a conditional branch code whose condition is always true / false based on the judgment to an unconditional branch code, The loop conditional branch code by unrolling means due to changes to the unconditional branch code is intended for causing a computer to function as dead code deleting means for deleting code that has become unnecessary, the computer reads the compiler stored in Possible recording media. A computer-readable recording medium storing a compiler that interprets a source program, generates intermediate text, and performs optimization to generate an object program , wherein the optimization is based on deletion of conditional branches in the loop And the compiler detects a loop detecting means for detecting a loop including an index having an initial value of 1 and an increment value of a constant, and a conditional branch code existing in the loop detected by the loop detecting means, Conditional branch that satisfies the requirement that the condition is a comparison between the result of the remainder and a constant, the dividend of the division for calculating the remainder is an index of the loop, and the divisor of the division is a positive integer constant A branch detecting means for detecting a code and recording information on the conditional branch code, and a conditional branch code detected by the branch detecting means. A value based on the unrolling number of loops in the recording information by the branch detection unit satisfies the requirement of "increment after unrolling processing is the least common multiple of the unrolling pretreatment increment and the divisor" including Unroll stage number determining means for determining to be a value divided by the increment value before unroll processing , unrolling the loop with the unroll stage number determined by the unroll stage number determining means, and developing each code in the unrolling For the condition of the conditional branch code detected by the branch detecting means from the information indicating how many stages the code is expanded in the process and the information recorded by the branch detecting means, Judge whether it will be false or not and whether it will be true or false, and the condition will always be true / false based on that decision Loop unrolling means for changing the branch code to unconditional branch code, and unnecessary code deleting means for deleting code that is no longer necessary due to the change from the conditional branch code to the unconditional branch code by the loop unrolling means As a computer-readable recording medium storing a compiler . A computer-readable recording medium in which the compiler is stored for generating an intermediate text by interpreting a source program with optimization to generate an object program, before Symbol optimization is based on the deletion of the conditional branch within the loop This is a optimization, and the compiler detects a loop detecting means for detecting a loop including an index having an initial value of 1 and an increment value of 1, and detects a conditional branch code existing in the loop detected by the loop detecting means. , “The condition is a comparison between the result of the remainder and a constant, the dividend to be used for calculating the remainder is an index of the loop, and the divisor of the division is a positive integer constant” Branch detection means for detecting a branch code and recording information on the conditional branch code, conditional branch code detected by the branch detection means The number of unrolled loops is determined to be a value smaller than the greatest common divisor of the divisor and the number of iterations of the loop in the information recorded by the branch detection means, and a value that is a divisor of the number of iterations of the loop Unrolling stage number determining means to perform unrolling of the loop with the unrolling stage number determined by the unrolling stage number determining means, and in the process of developing each code in the unrolling, in which code each code is expanded The condition of the conditional branch code detected by the branch detection means from the information indicating whether it is present and the information recorded by the branch detection means is “whether it is always true / false” or “true or false” Loop unrow that changes the conditional branch code that is always true / false based on the judgment to unconditional branch code Ring means, as well as causing a computer to function as dead code deleting means for deleting code that has become unnecessary due to the change from the conditional branch code to unconditional branch code by the loop unrolling unit, the compiler stores Computer-readable recording medium.

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