Refactor logic and add additional tests

Author: SahilPatidar

llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp

@@ -2758,9 +2758,10 @@ static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
   // -(X * C) --> X * (-C)
   if (match(FNegOp, m_FMul(m_Value(X), m_Constant(C))))
     if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL)) {
-      FastMathFlags Flag = I.getFastMathFlags() | FNegOp->getFastMathFlags();
-      Flag.setNoInfs(I.getFastMathFlags().noInfs() &&
-                     FNegOp->getFastMathFlags().noInfs());
+      FastMathFlags FMF = I.getFastMathFlags();
+      FastMathFlags OpFMF = FNegOp->getFastMathFlags();
+      FastMathFlags Flag = FMF | OpFMF;
+      Flag.setNoInfs(FMF.noInfs() && OpFMF.noInfs());
       return BinaryOperator::CreateFMulFMF(X, NegC, Flag);
     }
   // -(X / C) --> X / (-C)

llvm/test/Transforms/InstCombine/fneg.ll

@@ -1201,4 +1201,14 @@ define <2 x float> @test_fneg_nnan_ninf_mul_with_vec_const(<2 x float> %a) {
   ret <2 x float> %f2
 }
 
+define <2 x float> @test_fneg_nnan_ninf_mul_ninf_with_vec_const(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_nnan_ninf_mul_ninf_with_vec_const(
+; CHECK-NEXT:    [[F2:%.*]] = fmul nnan ninf <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT:    ret <2 x float> [[F2]]
+;
+  %f1 = fmul ninf <2 x float> %a, <float 0.000000, float -0.000000>
+  %f2 = fneg nnan ninf <2 x float> %f1
+  ret <2 x float> %f2
+}
+
 !0 = !{}