[llvm] 2d5e281 - [X86][AVX] Add a more aggressive SimplifyMultipleUseDemandedBits to simplify masked store masks.

[Simon Pilgrim via llvm-commits]

Author: Simon Pilgrim
Date: 2020-01-27T16:44:25Z
New Revision: 2d5e281b0fa0b5babcd48e47d64e94224aea4a1f

URL: https://github.com/llvm/llvm-project/commit/2d5e281b0fa0b5babcd48e47d64e94224aea4a1f
DIFF: https://github.com/llvm/llvm-project/commit/2d5e281b0fa0b5babcd48e47d64e94224aea4a1f.diff

LOG: [X86][AVX] Add a more aggressive SimplifyMultipleUseDemandedBits to simplify masked store masks.

Fixes a poor codegen issue noticed in PR11210.

Added: 
    

Modified: 
    llvm/lib/Target/X86/X86ISelLowering.cpp
    llvm/test/CodeGen/X86/masked_store.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 26a11dc4c548..153a22ef6ead 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -41716,9 +41716,16 @@ static SDValue combineMaskedStore(SDNode *N, SelectionDAG &DAG,
   // simplify ops leading up to it. We only demand the MSB of each lane.
   SDValue Mask = Mst->getMask();
   if (Mask.getScalarValueSizeInBits() != 1) {
-    APInt DemandedMask(APInt::getSignMask(VT.getScalarSizeInBits()));
-    if (TLI.SimplifyDemandedBits(Mask, DemandedMask, DCI))
+    APInt DemandedBits(APInt::getSignMask(VT.getScalarSizeInBits()));
+    if (TLI.SimplifyDemandedBits(Mask, DemandedBits, DCI))
       return SDValue(N, 0);
+    APInt DemandedElts = APInt::getAllOnesValue(VT.getVectorNumElements());
+    if (SDValue NewMask = TLI.SimplifyMultipleUseDemandedBits(
+            Mask, DemandedBits, DemandedElts, DAG, 0))
+      return DAG.getMaskedStore(Mst->getChain(), SDLoc(N), Mst->getValue(),
+                                Mst->getBasePtr(), Mst->getOffset(), NewMask,
+                                Mst->getMemoryVT(), Mst->getMemOperand(),
+                                Mst->getAddressingMode());
   }
 
   SDValue Value = Mst->getValue();

diff  --git a/llvm/test/CodeGen/X86/masked_store.ll b/llvm/test/CodeGen/X86/masked_store.ll
index efb061fdb53f..dc780060ae91 100644
--- a/llvm/test/CodeGen/X86/masked_store.ll
+++ b/llvm/test/CodeGen/X86/masked_store.ll
@@ -5126,8 +5126,6 @@ define void @PR11210(<4 x float> %x, <4 x float>* %ptr, <4 x float> %y, <2 x i64
 ;
 ; AVX1OR2-LABEL: PR11210:
 ; AVX1OR2:       ## %bb.0:
-; AVX1OR2-NEXT:    vpxor %xmm3, %xmm3, %xmm3
-; AVX1OR2-NEXT:    vpcmpgtd %xmm2, %xmm3, %xmm2
 ; AVX1OR2-NEXT:    vmaskmovps %xmm0, %xmm2, (%rdi)
 ; AVX1OR2-NEXT:    vmaskmovps %xmm1, %xmm2, (%rdi)
 ; AVX1OR2-NEXT:    retq