Commit Graph

7 Commits

Author SHA1 Message Date
Simon Pilgrim 193429ea15 Regenerate test in prep for SimplifyDemandedBits improvements.
llvm-svn: 349350
2018-12-17 12:48:34 +00:00
Andrea Di Biagio 46dcddb350 Teach DAGCombiner how to fold a SIGN_EXTEND_INREG of a BUILD_VECTOR of
ConstantSDNodes (or UNDEFs) into a simple BUILD_VECTOR.

For example, given the following sequence of dag nodes:

  i32 C = Constant<1>
  v4i32 V = BUILD_VECTOR C, C, C, C
  v4i32 Result = SIGN_EXTEND_INREG V, ValueType:v4i1

The SIGN_EXTEND_INREG node can be folded into a build_vector since
the vector in input is a BUILD_VECTOR of constants.

The optimized sequence is:

  i32 C = Constant<-1>
  v4i32 Result = BUILD_VECTOR C, C, C, C

llvm-svn: 198084
2013-12-27 20:20:28 +00:00
Nadav Rotem b532fca92c Revert r169638 because it broke Mesa llvmpipe tests.
Fix PR15239.

llvm-svn: 175985
2013-02-24 07:09:35 +00:00
Nadav Rotem ad0b5fbe8c When we use the BLEND instruction that uses the MSB as a mask, we can remove
the VSRI instruction before it since it does not affect the MSB.

Thanks Craig Topper for suggesting this.

llvm-svn: 169638
2012-12-07 21:43:11 +00:00
Nadav Rotem 6d31bac85e Revert 147426 because it caused pr11696.
llvm-svn: 147485
2012-01-03 22:19:42 +00:00
Nadav Rotem 6c7a0e6c8b Optimize the sequence blend(sign_extend(x)) to blend(shl(x)) since SSE blend instructions only look at the highest bit.
llvm-svn: 147426
2012-01-02 08:05:46 +00:00
Nadav Rotem 3c3dd6e588 PR11662.
Promotion of the mask operand needs to be done using PromoteTargetBoolean, and not padded with garbage.

llvm-svn: 147309
2011-12-28 13:08:20 +00:00