[PATCH] D25685: [DAG] use isConstOrConstSplat in ComputeNumSignBits to optimize SRA

Sanjay Patel via llvm-commits llvm-commits at lists.llvm.org
Mon Oct 17 13:50:55 PDT 2016


This revision was automatically updated to reflect the committed changes.
Closed by commit rL284424: [DAG] use isConstOrConstSplat in ComputeNumSignBits to optimize SRA (authored by spatel).

Changed prior to commit:
  https://reviews.llvm.org/D25685?vs=74865&id=74896#toc

Repository:
  rL LLVM

https://reviews.llvm.org/D25685

Files:
  llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
  llvm/trunk/test/CodeGen/X86/sar_fold64.ll


Index: llvm/trunk/test/CodeGen/X86/sar_fold64.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/sar_fold64.ll
+++ llvm/trunk/test/CodeGen/X86/sar_fold64.ll
@@ -80,16 +80,6 @@
 ; CHECK-NEXT:    pxor %xmm1, %xmm1
 ; CHECK-NEXT:    psubd %xmm0, %xmm1
 ; CHECK-NEXT:    movdqa %xmm1, %xmm0
-; CHECK-NEXT:    psrad $31, %xmm0
-; CHECK-NEXT:    movdqa %xmm1, %xmm2
-; CHECK-NEXT:    movsd {{.*#+}} xmm2 = xmm0[0],xmm2[1]
-; CHECK-NEXT:    pshufd {{.*#+}} xmm2 = xmm2[1,3,2,3]
-; CHECK-NEXT:    movdqa %xmm1, %xmm0
-; CHECK-NEXT:    psrad $5, %xmm0
-; CHECK-NEXT:    psrad $1, %xmm1
-; CHECK-NEXT:    movsd {{.*#+}} xmm0 = xmm1[0],xmm0[1]
-; CHECK-NEXT:    pshufd {{.*#+}} xmm0 = xmm0[0,2,2,3]
-; CHECK-NEXT:    punpckldq {{.*#+}} xmm0 = xmm0[0],xmm2[0],xmm0[1],xmm2[1]
 ; CHECK-NEXT:    retq
 ;
   %and = and <4 x i32> %x, <i32 1, i32 1, i32 1 , i32 1>
Index: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2697,7 +2697,7 @@
     if (Tmp2 == 1) return 1;
 
     // Handle NEG.
-    if (ConstantSDNode *CLHS = dyn_cast<ConstantSDNode>(Op.getOperand(0)))
+    if (ConstantSDNode *CLHS = isConstOrConstSplat(Op.getOperand(0)))
       if (CLHS->isNullValue()) {
         APInt KnownZero, KnownOne;
         computeKnownBits(Op.getOperand(1), KnownZero, KnownOne, Depth+1);


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