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| author | Fangrui Song <maskray@google.com> | 2020-08-04 17:50:06 -0700 |
|---|---|---|
| committer | Fangrui Song <maskray@google.com> | 2020-08-04 17:50:06 -0700 |
| commit | 0c7af8c83bd1acb0ca78f35ddde29b6fde4363a0 (patch) | |
| tree | c45ef9375d6ec68137da9aa6f522594989b4e043 /llvm/unittests/ProfileData/CoverageMappingTest.cpp | |
| parent | 4c9ed3ed3d2fc7622acf5fc0d80ad20b44cf376a (diff) | |
| download | llvm-0c7af8c83bd1acb0ca78f35ddde29b6fde4363a0.zip llvm-0c7af8c83bd1acb0ca78f35ddde29b6fde4363a0.tar.gz llvm-0c7af8c83bd1acb0ca78f35ddde29b6fde4363a0.tar.bz2 | |
[X86] Optimize getImpliedDisabledFeatures & getImpliedEnabledFeatures after D83273
Previously the time complexity is O(|number of paths from the root to an
implied feature| * CPU_FWATURE_MAX) where CPU_FEATURE_MAX is 92.
The number of paths can be large (theoretically exponential).
For an inline asm statement, there is a code path
`clang::Parser::ParseAsmStatement -> clang::Sema::ActOnGCCAsmStmt -> ASTContext::getFunctionFeatureMap`
leading to potentially many calls of getImpliedEnabledFeatures (41 for my -march=native case).
We should improve the performance a bit in case the number of inline asm
statements is large (Linux kernel builds).
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D85257
Diffstat (limited to 'llvm/unittests/ProfileData/CoverageMappingTest.cpp')
0 files changed, 0 insertions, 0 deletions