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| author | Benjamin Kramer <benny.kra@googlemail.com> | 2011-03-17 20:39:14 +0000 |
|---|---|---|
| committer | Benjamin Kramer <benny.kra@googlemail.com> | 2011-03-17 20:39:14 +0000 |
| commit | 1c10b8de46ce8e39178eeded4786b1e53722f099 (patch) | |
| tree | eac996256e2784243c516affcd8e5910c3226ec9 /configure | |
| parent | d9103df51b858cf051a1650ac7eb33d416e9ac41 (diff) | |
| download | external_llvm-1c10b8de46ce8e39178eeded4786b1e53722f099.zip external_llvm-1c10b8de46ce8e39178eeded4786b1e53722f099.tar.gz external_llvm-1c10b8de46ce8e39178eeded4786b1e53722f099.tar.bz2 | |
BuildUDIV: If the divisor is even we can simplify the fixup of the multiplied value by introducing an early shift.
This allows us to compile "unsigned foo(unsigned x) { return x/28; }" into
shrl $2, %edi
imulq $613566757, %rdi, %rax
shrq $32, %rax
ret
instead of
movl %edi, %eax
imulq $613566757, %rax, %rcx
shrq $32, %rcx
subl %ecx, %eax
shrl %eax
addl %ecx, %eax
shrl $4, %eax
on x86_64
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127829 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'configure')
0 files changed, 0 insertions, 0 deletions