Propagate the FNegOp FMF flag instead of I.

Author: SahilPatidar

llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp

@@ -2741,22 +2741,6 @@ Instruction *InstCombinerImpl::visitSub(BinaryOperator &I) {
   return TryToNarrowDeduceFlags();
 }
 
-static FastMathFlags getCorrectFMFForFNeg(FastMathFlags F1, FastMathFlags F2) {
-
-  FastMathFlags NF1 = F1 & F2;
-  FastMathFlags NF2 = F1 | F2;
-  if (NF2.noNaNs())
-    return F2;
-
-  if (NF1.any() || (F1.none() && F2.none()))
-    return NF1;
-
-  if (F1.all() || F2.all())
-    return F2;
-
-  return NF1;
-}
-
 /// This eliminates floating-point negation in either 'fneg(X)' or
 /// 'fsub(-0.0, X)' form by combining into a constant operand.
 static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
@@ -2773,15 +2757,8 @@ static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
   // Fold negation into constant operand.
   // -(X * C) --> X * (-C)
   if (match(FNegOp, m_FMul(m_Value(X), m_Constant(C))))
-    if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL)) {
-      FastMathFlags FMF = cast<FPMathOperator>(I.getOperand(0))->getFastMathFlags();
-      if (I.getFastMathFlags().noInfs()) {
-          return BinaryOperator::CreateFMulFMF(
-            X, NegC,
-            getCorrectFMFForFNeg(I.getFastMathFlags(), FMF));
-      }
-      return BinaryOperator::CreateFMulFMF(X, NegC, &I);
-    }
+    if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL))
+      return BinaryOperator::CreateFMulFMF(X, NegC, FNegOp);
   // -(X / C) --> X / (-C)
   if (match(FNegOp, m_FDiv(m_Value(X), m_Constant(C))))
     if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL))

llvm/test/Transforms/InstCombine/fneg.ll

@@ -41,7 +41,7 @@ define float @fmul_fneg(float %x) {
 
 define float @fmul_fsub_fmf(float %x) {
 ; CHECK-LABEL: @fmul_fsub_fmf(
-; CHECK-NEXT:    [[R:%.*]] = fmul reassoc nsz float [[X:%.*]], -4.200000e+01
+; CHECK-NEXT:    [[R:%.*]] = fmul float [[X:%.*]], -4.200000e+01
 ; CHECK-NEXT:    ret float [[R]]
 ;
   %m = fmul float %x, 42.0
@@ -51,7 +51,7 @@ define float @fmul_fsub_fmf(float %x) {
 
 define float @fmul_fneg_fmf(float %x) {
 ; CHECK-LABEL: @fmul_fneg_fmf(
-; CHECK-NEXT:    [[R:%.*]] = fmul reassoc nsz float [[X:%.*]], -4.200000e+01
+; CHECK-NEXT:    [[R:%.*]] = fmul float [[X:%.*]], -4.200000e+01
 ; CHECK-NEXT:    ret float [[R]]
 ;
   %m = fmul float %x, 42.0
@@ -1121,31 +1121,30 @@ define float @test_fneg_ninf_mul_with_anyzero(float %a) {
 
 define float @test_fsub_ninf_mul_with_anyzero(float %a) {
 ; CHECK-LABEL: @test_fsub_ninf_mul_with_anyzero(
-; CHECK-NEXT:    [[F2:%.*]] = fmul float [[A:%.*]], -0.000000e+00
+; CHECK-NEXT:    [[F2:%.*]] = fmul nsz float [[A:%.*]], -0.000000e+00
 ; CHECK-NEXT:    ret float [[F2]]
 ;
-  %f1 = fmul float %a, 0.000000
+  %f1 = fmul nsz float %a, 0.000000
   %f2 = fsub ninf float -0.000000, %f1
   ret float %f2
 }
 
 define float @test_fneg_nnan_mul_with_anyzero(float %a) {
 ; CHECK-LABEL: @test_fneg_nnan_mul_with_anyzero(
-; CHECK-NEXT:    [[TMP1:%.*]] = fneg nnan float [[A:%.*]]
-; CHECK-NEXT:    [[F2:%.*]] = call nnan float @llvm.copysign.f32(float 0.000000e+00, float [[TMP1]])
+; CHECK-NEXT:    [[F2:%.*]] = fmul ninf float [[A:%.*]], -0.000000e+00
 ; CHECK-NEXT:    ret float [[F2]]
 ;
-  %f1 = fmul float %a, 0.000000
+  %f1 = fmul ninf float %a, 0.000000
   %f2 = fneg nnan float %f1
   ret float %f2
 }
 
 define float @test_fneg_nsz_mul_with_anyzero(float %a) {
 ; CHECK-LABEL: @test_fneg_nsz_mul_with_anyzero(
-; CHECK-NEXT:    [[F2:%.*]] = fmul nsz float [[A:%.*]], -0.000000e+00
+; CHECK-NEXT:    [[F2:%.*]] = fmul ninf float [[A:%.*]], -0.000000e+00
 ; CHECK-NEXT:    ret float [[F2]]
 ;
-  %f1 = fmul float %a, 0.000000
+  %f1 = fmul ninf float %a, 0.000000
   %f2 = fneg nsz float %f1
   ret float %f2
 }
@@ -1163,7 +1162,7 @@ define float @test_fneg_ninf_mul_nnan_with_const(float %a) {
 
 define float @test_fneg_ninf_mul_nsz_with_const(float %a) {
 ; CHECK-LABEL: @test_fneg_ninf_mul_nsz_with_const(
-; CHECK-NEXT:    [[F2:%.*]] = fmul float [[A:%.*]], -0.000000e+00
+; CHECK-NEXT:    [[F2:%.*]] = fmul nsz float [[A:%.*]], -0.000000e+00
 ; CHECK-NEXT:    ret float [[F2]]
 ;
   %f1 = fmul nsz float %a, 0.000000
@@ -1183,13 +1182,22 @@ define <2 x float> @test_fneg_ninf_mul_nnan_with_vec_const(<2 x float> %a) {
 
 define <2 x float> @test_fneg_ninf_mul_nsz_with_vec_const(<2 x float> %a) {
 ; CHECK-LABEL: @test_fneg_ninf_mul_nsz_with_vec_const(
-; CHECK-NEXT:    [[F2:%.*]] = fmul <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT:    [[F2:%.*]] = fmul nsz <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
 ; CHECK-NEXT:    ret <2 x float> [[F2]]
 ;
   %f1 = fmul nsz <2 x float> %a, <float 0.000000, float -0.000000>
   %f2 = fneg ninf <2 x float> %f1
   ret <2 x float> %f2
 }
 
+define <2 x float> @test_fneg_nnan_ninf_mul_with_vec_const(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_nnan_ninf_mul_with_vec_const(
+; CHECK-NEXT:    [[F2:%.*]] = fmul <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT:    ret <2 x float> [[F2]]
+;
+  %f1 = fmul <2 x float> %a, <float 0.000000, float -0.000000>
+  %f2 = fneg nnan ninf <2 x float> %f1
+  ret <2 x float> %f2
+}
 
 !0 = !{}

llvm/test/Transforms/InstCombine/fsub.ll

@@ -98,7 +98,7 @@ define float @sub_sub_nsz(float %x, float %y, float %z) {
 
 define float @sub_add_neg_x(float %x, float %y) {
 ; CHECK-LABEL: @sub_add_neg_x(
-; CHECK-NEXT:    [[R:%.*]] = fmul reassoc nsz float [[X:%.*]], -5.000000e+00
+; CHECK-NEXT:    [[R:%.*]] = fmul float [[X:%.*]], -5.000000e+00
 ; CHECK-NEXT:    ret float [[R]]
 ;
   %mul = fmul float %x, 5.000000e+00