diff options
| author | Nadav Rotem <nrotem@apple.com> | 2012-12-07 21:43:11 +0000 |
|---|---|---|
| committer | Nadav Rotem <nrotem@apple.com> | 2012-12-07 21:43:11 +0000 |
| commit | af59e9adbd4c972d480d58260b03768c85eb2067 (patch) | |
| tree | 394a45431b1053aa03cd907b52b102394461c5fc | |
| parent | 829c8bd98db63bc57f2e6c21bfcd5464f08ef548 (diff) | |
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169638 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Target/X86/X86ISelLowering.cpp | 7 | ||||
| -rw-r--r-- | test/CodeGen/X86/2011-12-28-vselecti8.ll | 2 | ||||
| -rw-r--r-- | test/CodeGen/X86/blend-msb.ll | 2 |
3 files changed, 8 insertions, 3 deletions
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp index d48d722fab..8f7f38d012 100644 --- a/lib/Target/X86/X86ISelLowering.cpp +++ b/lib/Target/X86/X86ISelLowering.cpp @@ -15675,6 +15675,11 @@ static SDValue PerformOrCombine(SDNode *N, SelectionDAG &DAG, DebugLoc DL = N->getDebugLoc(); + // We are going to replace the AND, OR, NAND with either BLEND + // or PSIGN, which only look at the MSB. The VSRAI instruction + // does not affect the highest bit, so we can get rid of it. + Mask = Mask.getOperand(0); + // Now we know we at least have a plendvb with the mask val. See if // we can form a psignb/w/d. // psign = x.type == y.type == mask.type && y = sub(0, x); @@ -15683,7 +15688,7 @@ static SDValue PerformOrCombine(SDNode *N, SelectionDAG &DAG, X.getValueType() == MaskVT && Y.getValueType() == MaskVT) { assert((EltBits == 8 || EltBits == 16 || EltBits == 32) && "Unsupported VT for PSIGN"); - Mask = DAG.getNode(X86ISD::PSIGN, DL, MaskVT, X, Mask.getOperand(0)); + Mask = DAG.getNode(X86ISD::PSIGN, DL, MaskVT, X, Mask); return DAG.getNode(ISD::BITCAST, DL, VT, Mask); } // PBLENDVB only available on SSE 4.1 diff --git a/test/CodeGen/X86/2011-12-28-vselecti8.ll b/test/CodeGen/X86/2011-12-28-vselecti8.ll index dbc122ac6e..1a9d46d1e2 100644 --- a/test/CodeGen/X86/2011-12-28-vselecti8.ll +++ b/test/CodeGen/X86/2011-12-28-vselecti8.ll @@ -5,7 +5,7 @@ target triple = "x86_64-apple-darwin11.2.0" ; CHECK: @foo8 ; CHECK: psll -; CHECK: psraw +; CHECK-NOT: psraw ; CHECK: pblendvb ; CHECK: ret define void @foo8(float* nocapture %RET) nounwind { diff --git a/test/CodeGen/X86/blend-msb.ll b/test/CodeGen/X86/blend-msb.ll index 11f811f8cf..34445428ea 100644 --- a/test/CodeGen/X86/blend-msb.ll +++ b/test/CodeGen/X86/blend-msb.ll @@ -28,7 +28,7 @@ define <4 x i8> @vsel_4xi8(<4 x i8> %v1, <4 x i8> %v2) { ; reduce the mask in this case. ;CHECK: vsel_8xi16 ;CHECK: psllw -;CHECK: psraw +;CHECK-NOT: psraw ;CHECK: pblendvb ;CHECK: ret define <8 x i16> @vsel_8xi16(<8 x i16> %v1, <8 x i16> %v2) { |