[TargetLowering] SimplifyDemandedVectorElts - pass demanded elts through ADD/SUB ops

llvm-svn: 326044

diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 36cb2cd..cb737dc 100644 (file)
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -1536,6 +1536,19 @@ bool TargetLowering::SimplifyDemandedVectorElts(
     }
     break;
   }
+  case ISD::ADD:
+  case ISD::SUB: {
+    APInt SrcUndef, SrcZero;
+    if (SimplifyDemandedVectorElts(Op.getOperand(1), DemandedElts, SrcUndef,
+                                   SrcZero, TLO, Depth + 1))
+      return true;
+    if (SimplifyDemandedVectorElts(Op.getOperand(0), DemandedElts, KnownUndef,
+                                   KnownZero, TLO, Depth + 1))
+      return true;
+    KnownZero &= SrcZero;
+    KnownUndef &= SrcUndef;
+    break;
+  }
   case ISD::TRUNCATE:
     if (SimplifyDemandedVectorElts(Op.getOperand(0), DemandedElts, KnownUndef,
                                    KnownZero, TLO, Depth + 1))

diff --git a/llvm/test/CodeGen/X86/widen_conv-1.ll b/llvm/test/CodeGen/X86/widen_conv-1.ll
index 7e0f999..123e443 100644 (file)
--- a/llvm/test/CodeGen/X86/widen_conv-1.ll
+++ b/llvm/test/CodeGen/X86/widen_conv-1.ll
@@ -8,7 +8,8 @@ define void @convert_v2i64_to_v2i32(<2 x i32>* %dst.addr, <2 x i64> %src) nounwi
 ; X86-LABEL: convert_v2i64_to_v2i32:
 ; X86:       # %bb.0: # %entry
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %eax
-; X86-NEXT:    paddd {{\.LCPI.*}}, %xmm0
+; X86-NEXT:    pcmpeqd %xmm1, %xmm1
+; X86-NEXT:    psubd %xmm1, %xmm0
 ; X86-NEXT:    pshufd {{.*#+}} xmm0 = xmm0[0,2,2,3]
 ; X86-NEXT:    movq %xmm0, (%eax)
 ; X86-NEXT:    retl