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| author | Evan Cheng <evan.cheng@apple.com> | 2009-03-28 05:57:29 +0000 |
|---|---|---|
| committer | Evan Cheng <evan.cheng@apple.com> | 2009-03-28 05:57:29 +0000 |
| commit | 0b0cd9113af42c422c829563c3b12e6e52bd2d79 (patch) | |
| tree | 9b3c7aba0c5687a35d4f494df6b4bc6de48f3f71 /llvm.spec.in | |
| parent | e8b64106ecf1057c7506d44ec8f64b5c83ee51c7 (diff) | |
| download | external_llvm-0b0cd9113af42c422c829563c3b12e6e52bd2d79.zip external_llvm-0b0cd9113af42c422c829563c3b12e6e52bd2d79.tar.gz external_llvm-0b0cd9113af42c422c829563c3b12e6e52bd2d79.tar.bz2 | |
Optimize some 64-bit multiplication by constants into two lea's or one lea + shl since imulq is slow (latency 5). e.g.
x * 40
=>
shlq $3, %rdi
leaq (%rdi,%rdi,4), %rax
This has the added benefit of allowing more multiply to be folded into addressing mode. e.g.
a * 24 + b
=>
leaq (%rdi,%rdi,2), %rax
leaq (%rsi,%rax,8), %rax
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67917 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'llvm.spec.in')
0 files changed, 0 insertions, 0 deletions