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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41359 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2007-08-24 15:17:59 +00:00
parent 4259fe3281
commit b23f4c5f44
1 changed files with 14 additions and 0 deletions
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14
lib/Target/X86/README-SSE.txt
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@ -630,3 +630,17 @@ _bar:
ret
//===---------------------------------------------------------------------===//
We should materialize vecetor constants like "all ones" and "signbit" with
code like:
cmpeqps xmm1, xmm1 ; xmm1 = all-ones
and:
cmpeqps xmm1, xmm1 ; xmm1 = all-ones
psrlq xmm1, 31 ; xmm1 = all 100000000000...
instead of using a load from the constant pool. The later is important for
ABS/NEG/copysign etc.
//===---------------------------------------------------------------------===//