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Revision tags: llvmorg-20.1.0, llvmorg-20.1.0-rc3, llvmorg-20.1.0-rc2, llvmorg-20.1.0-rc1, llvmorg-21-init, llvmorg-19.1.7, llvmorg-19.1.6, llvmorg-19.1.5, llvmorg-19.1.4, llvmorg-19.1.3, llvmorg-19.1.2, llvmorg-19.1.1, llvmorg-19.1.0, llvmorg-19.1.0-rc4, llvmorg-19.1.0-rc3, llvmorg-19.1.0-rc2, llvmorg-19.1.0-rc1, llvmorg-20-init, llvmorg-18.1.8, llvmorg-18.1.7, llvmorg-18.1.6, llvmorg-18.1.5, llvmorg-18.1.4, llvmorg-18.1.3, llvmorg-18.1.2, llvmorg-18.1.1, llvmorg-18.1.0, llvmorg-18.1.0-rc4, llvmorg-18.1.0-rc3, llvmorg-18.1.0-rc2, llvmorg-18.1.0-rc1, llvmorg-19-init, llvmorg-17.0.6, llvmorg-17.0.5, llvmorg-17.0.4, llvmorg-17.0.3, llvmorg-17.0.2, llvmorg-17.0.1, llvmorg-17.0.0, llvmorg-17.0.0-rc4, llvmorg-17.0.0-rc3, llvmorg-17.0.0-rc2, llvmorg-17.0.0-rc1, llvmorg-18-init, llvmorg-16.0.6, llvmorg-16.0.5, llvmorg-16.0.4, llvmorg-16.0.3, llvmorg-16.0.2, llvmorg-16.0.1, llvmorg-16.0.0, llvmorg-16.0.0-rc4, llvmorg-16.0.0-rc3, llvmorg-16.0.0-rc2, llvmorg-16.0.0-rc1, llvmorg-17-init, llvmorg-15.0.7, llvmorg-15.0.6, llvmorg-15.0.5, llvmorg-15.0.4, llvmorg-15.0.3, llvmorg-15.0.2, llvmorg-15.0.1, llvmorg-15.0.0, llvmorg-15.0.0-rc3, llvmorg-15.0.0-rc2, llvmorg-15.0.0-rc1, llvmorg-16-init, llvmorg-14.0.6, llvmorg-14.0.5, llvmorg-14.0.4, llvmorg-14.0.3, llvmorg-14.0.2, llvmorg-14.0.1, llvmorg-14.0.0, llvmorg-14.0.0-rc4, llvmorg-14.0.0-rc3, llvmorg-14.0.0-rc2, llvmorg-14.0.0-rc1 |
| #
687e4af1 |
| 08-Feb-2022 |
Amir Ayupov <[email protected]> |
[BOLT] CMOVConversion pass
Convert simple hammocks into cmov based on misprediction rate.
Test Plan:
- Assembly test: `cmov-conversion.s`
- Testing on a binary:
# Bootstrap clang with `-x86-cmov-
[BOLT] CMOVConversion pass
Convert simple hammocks into cmov based on misprediction rate.
Test Plan:
- Assembly test: `cmov-conversion.s`
- Testing on a binary:
# Bootstrap clang with `-x86-cmov-converter-force-all` and `-Wl,--emit-relocs`
(Release build)
# Collect perf.data:
- `clang++ <opts> bolt/lib/Core/BinaryFunction.cpp -E > bf.cpp`
- `perf record -e cycles:u -j any,u -- clang-15 bf.cpp -O2 -std=c++14 -c -o bf.o`
# Optimize clang-15 with and w/o -cmov-conversion:
- `llvm-bolt clang-15 -p perf.data -o clang-15.bolt`
- `llvm-bolt clang-15 -p perf.data -cmov-conversion -o clang-15.bolt.cmovconv`
# Run perf experiment:
- test: `clang-15.bolt.cmovconv`,
- control: `clang-15.bolt`,
- workload (clang options): `bf.cpp -O2 -std=c++14 -c -o bf.o`
Results:
```
task-clock [delta: -360.21 ± 356.75, delta(%): -1.7760 ± 1.7589, p-value: 0.047951, balance: -6]
instructions [delta: 44061118 ± 13246382, delta(%): 0.0690 ± 0.0207, p-value: 0.000001, balance: 50]
icache-misses [delta: -5534468 ± 2779620, delta(%): -0.4331 ± 0.2175, p-value: 0.028014, balance: -28]
branch-misses [delta: -1624270 ± 1113244, delta(%): -0.3456 ± 0.2368, p-value: 0.030300, balance: -22]
```
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D120177
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