[llvm] r253997 - [InstCombine] fix propagation of fast-math-flags

[Sanjay Patel via llvm-commits]

Author: spatel
Date: Tue Nov 24 11:51:20 2015
New Revision: 253997

URL: http://llvm.org/viewvc/llvm-project?rev=253997&view=rev
Log:
[InstCombine] fix propagation of fast-math-flags

Noticed while working on D4583:
http://reviews.llvm.org/D4583


Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
    llvm/trunk/test/Transforms/InstCombine/vec_shuffle.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp?rev=253997&r1=253996&r2=253997&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp Tue Nov 24 11:51:20 2015
@@ -1245,16 +1245,11 @@ Value *InstCombiner::Descale(Value *Val,
 /// specified one but with other operands.
 static Value *CreateBinOpAsGiven(BinaryOperator &Inst, Value *LHS, Value *RHS,
                                  InstCombiner::BuilderTy *B) {
-  Value *BORes = B->CreateBinOp(Inst.getOpcode(), LHS, RHS);
-  if (BinaryOperator *NewBO = dyn_cast<BinaryOperator>(BORes)) {
-    if (isa<OverflowingBinaryOperator>(NewBO)) {
-      NewBO->setHasNoSignedWrap(Inst.hasNoSignedWrap());
-      NewBO->setHasNoUnsignedWrap(Inst.hasNoUnsignedWrap());
-    }
-    if (isa<PossiblyExactOperator>(NewBO))
-      NewBO->setIsExact(Inst.isExact());
-  }
-  return BORes;
+  Value *BO = B->CreateBinOp(Inst.getOpcode(), LHS, RHS);
+  // If LHS and RHS are constant, BO won't be a binary operator.
+  if (BinaryOperator *NewBO = dyn_cast<BinaryOperator>(BO))
+    NewBO->copyIRFlags(&Inst);
+  return BO;
 }
 
 /// \brief Makes transformation of binary operation specific for vector types.

Modified: llvm/trunk/test/Transforms/InstCombine/vec_shuffle.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/vec_shuffle.ll?rev=253997&r1=253996&r2=253997&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/vec_shuffle.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/vec_shuffle.ll Tue Nov 24 11:51:20 2015
@@ -310,16 +310,16 @@ define <4 x i32> @shuffle_17addnuw(<4 x
   ret <4 x i32> %r
 }
 
-define <4 x float> @shuffle_17fsub(<4 x float> %v1, <4 x float> %v2) nounwind uwtable {
-; CHECK-LABEL: @shuffle_17fsub(
-; CHECK-NOT: shufflevector
-; CHECK: fsub <4 x float> %v1, %v2
-; CHECK: shufflevector
+define <4 x float> @shuffle_17fsub_fast(<4 x float> %v1, <4 x float> %v2) nounwind uwtable {
+; CHECK-LABEL: @shuffle_17fsub_fast(
+; CHECK-NEXT: [[VAR1:%[a-zA-Z0-9.]+]] = fsub fast <4 x float> %v1, %v2
+; CHECK-NEXT: shufflevector <4 x float> [[VAR1]], <4 x float> undef, <4 x i32> <i32 1, i32 2, i32 3, i32 0>
+; CHECK-NEXT: ret <4 x float>
   %t1 = shufflevector <4 x float> %v1, <4 x float> zeroinitializer,
                       <4 x i32> <i32 1, i32 2, i32 3, i32 0>
   %t2 = shufflevector <4 x float> %v2, <4 x float> zeroinitializer,
                       <4 x i32> <i32 1, i32 2, i32 3, i32 0>
-  %r = fsub <4 x float> %t1, %t2
+  %r = fsub fast <4 x float> %t1, %t2
   ret <4 x float> %r
 }