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| author | Hal Finkel <hfinkel@anl.gov> | 2013-11-01 10:58:22 +0000 |
|---|---|---|
| committer | Hal Finkel <hfinkel@anl.gov> | 2013-11-01 10:58:22 +0000 |
| commit | 4d94930bcbdcdeb264ac5479ae292c1d91e6d719 (patch) | |
| tree | b837c613d79908c8487f07a52e99dc0fbf089b91 /llvm/lib/Bitcode/Writer/BitcodeWriter.cpp | |
| parent | 1d1debf1264d2ca2e26a0d55b1f4076176ad1590 (diff) | |
| download | llvm-4d94930bcbdcdeb264ac5479ae292c1d91e6d719.zip llvm-4d94930bcbdcdeb264ac5479ae292c1d91e6d719.tar.gz llvm-4d94930bcbdcdeb264ac5479ae292c1d91e6d719.tar.bz2 | |
Consider (x == -1) unlikely in BranchProbabilityInfo
This adds another heuristic to BPI, similar to the existing heuristic that
considers (x == 0) unlikely to be true. As suggested in the PACT'98 paper by
Deitrich, Cheng, and Hwu, -1 is often used to indicate an invalid index, and
equality comparisons with -1 are also unlikely to succeed. Local
experimentation supports this hypothesis: This yields a 1-2% speedup in the
test-suite sqlite benchmark on the PPC A2 core, with no significant
regressions.
llvm-svn: 193855
Diffstat (limited to 'llvm/lib/Bitcode/Writer/BitcodeWriter.cpp')
0 files changed, 0 insertions, 0 deletions