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Micro-optimization -- missed LICM opportunity.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42542 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2007-10-02 19:55:05 +00:00
parent fcd78f88f3
commit c720279ac7
1 changed files with 24 additions and 0 deletions
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24
lib/Target/X86/README-SSE.txt
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@ -671,3 +671,27 @@ beneficial because it prevents the load from being folded into the multiply.
//===---------------------------------------------------------------------===//
In this loop:
LBB4_6: # bb47.preheader
shlw $2, %si
decw %si
movzwl %si, %eax
incl %eax
xorl %ecx, %ecx
LBB4_7: # bb47
xorps %xmm0, %xmm0 # (1)
movaps %xmm0, (%edx)
movaps %xmm0, 16(%edx)
addl $32, %edx
incl %ecx
cmpl %eax, %ecx
jne LBB4_7 # bb47
LBB4_8: # bb42.return_crit_edge
xorw %si, %si
jmp LBB4_12 # return
The instruction at (1) can be moved out of the main body of the loop.
//===---------------------------------------------------------------------===//