-
Notifications
You must be signed in to change notification settings - Fork 12.6k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
[Driver, CodeGen] pass through and apply -fassociative-math
There are 2 parts to getting the -fassociative-math command-line flag translated to LLVM FMF: 1. In the driver/frontend, we accept the flag and its 'no' inverse and deal with the interactions with other flags like -ffast-math -fno-signed-zeros -fno-trapping-math. This was mostly already done - we just need to translate the flag as a codegen option. The test file is complicated because there are many potential combinations of flags here. Note that we are matching gcc's behavior that requires 'nsz' and no-trapping-math. 2. In codegen, we map the codegen option to FMF in the IR builder. This is simple code and corresponding test. For the motivating example from PR27372: float foo(float a, float x) { return ((a + x) - x); } $ ./clang -O2 27372.c -S -o - -ffast-math -fno-associative-math -emit-llvm | egrep 'fadd|fsub' %add = fadd nnan ninf nsz arcp contract float %0, %1 %sub = fsub nnan ninf nsz arcp contract float %add, %2 So 'reassoc' is off as expected (and so is the new 'afn' but that's a different patch). This case now works as expected end-to-end although the underlying logic is still wrong: $ ./clang -O2 27372.c -S -o - -ffast-math -fno-associative-math | grep xmm addss %xmm1, %xmm0 subss %xmm1, %xmm0 We're not done because the case where 'reassoc' is set is ignored by optimizer passes. Example: $ ./clang -O2 27372.c -S -o - -fassociative-math -fno-signed-zeros -fno-trapping-math -emit-llvm | grep fadd %add = fadd reassoc float %0, %1 $ ./clang -O2 27372.c -S -o - -fassociative-math -fno-signed-zeros -fno-trapping-math | grep xmm addss %xmm1, %xmm0 subss %xmm1, %xmm0 Differential Revision: https://reviews.llvm.org/D39812 llvm-svn: 320920
- Loading branch information
1 parent
5028ace
commit cb8c009
Showing
7 changed files
with
62 additions
and
13 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters