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| author | Benjamin Kramer <benny.kra@googlemail.com> | 2011-12-24 11:23:32 +0000 |
|---|---|---|
| committer | Benjamin Kramer <benny.kra@googlemail.com> | 2011-12-24 11:23:32 +0000 |
| commit | 32d720bb2f733684880c9720855e0d44097c1f44 (patch) | |
| tree | a0c877bd857a562e578f6df839a3d65805a75f07 /lib/Target/X86/README.txt | |
| parent | d873a4b89b365f1e58e808109cd77034517f095d (diff) | |
| download | llvm-32d720bb2f733684880c9720855e0d44097c1f44.tar.gz llvm-32d720bb2f733684880c9720855e0d44097c1f44.tar.bz2 llvm-32d720bb2f733684880c9720855e0d44097c1f44.tar.xz | |
Chandler fixed this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147247 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/X86/README.txt')
| -rw-r--r-- | lib/Target/X86/README.txt | 32 |
1 files changed, 0 insertions, 32 deletions
diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt index b407955060..51722b2248 100644 --- a/lib/Target/X86/README.txt +++ b/lib/Target/X86/README.txt @@ -2060,35 +2060,3 @@ Instead we could generate: The trick is to match "fetch_and_add(X, -C) == C". //===---------------------------------------------------------------------===// - -unsigned log2(unsigned x) { - return x > 1 ? 32-__builtin_clz(x-1) : 0; -} - -generates (x86_64): - xorl %eax, %eax - cmpl $2, %edi - jb LBB0_2 -## BB#1: - decl %edi - movl $63, %ecx - bsrl %edi, %eax - cmovel %ecx, %eax - xorl $-32, %eax - addl $33, %eax -LBB0_2: - ret - -The cmov and the early test are redundant: - xorl %eax, %eax - cmpl $2, %edi - jb LBB0_2 -## BB#1: - decl %edi - bsrl %edi, %eax - xorl $-32, %eax - addl $33, %eax -LBB0_2: - ret - -//===---------------------------------------------------------------------===// |