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[InstCombine] allow fsub+fmul FMF folds for vectors

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llvm-svn: 339368
This commit is contained in:
Sanjay Patel 2018-08-09 18:42:12 +00:00
parent 598c70deb8
commit b8574681f1
2 changed files with 17 additions and 8 deletions
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11
lib/Transforms/InstCombine/InstCombineAddSub.cpp
View File

@ -1914,6 +1914,17 @@ Instruction *InstCombiner::visitFSub(BinaryOperator &I) {
if (match(Op1, m_c_FAdd(m_Specific(Op0), m_Value(X))))
return BinaryOperator::CreateFNegFMF(X, &I);
// (X * C) - X --> X * (C - 1.0)
if (match(Op0, m_FMul(m_Specific(Op1), m_Constant(C)))) {
Constant *CSubOne = ConstantExpr::getFSub(C, ConstantFP::get(Ty, 1.0));
return BinaryOperator::CreateFMulFMF(Op1, CSubOne, &I);
}
// X - (X * C) --> X * (1.0 - C)
if (match(Op1, m_FMul(m_Specific(Op0), m_Constant(C)))) {
Constant *OneSubC = ConstantExpr::getFSub(ConstantFP::get(Ty, 1.0), C);
return BinaryOperator::CreateFMulFMF(Op0, OneSubC, &I);
}
// TODO: This performs reassociative folds for FP ops. Some fraction of the
// functionality has been subsumed by simple pattern matching here and in
// InstSimplify. We should let a dedicated reassociation pass handle more

14
test/Transforms/InstCombine/fast-math.ll
View File

@ -442,8 +442,8 @@ define double @fail2(double %f1, double %f2) {
define float @fsub_op0_fmul_const(float %x) {
; CHECK-LABEL: @fsub_op0_fmul_const(
; CHECK-NEXT: [[TMP1:%.*]] = fmul reassoc nsz float [[X:%.*]], 6.000000e+00
; CHECK-NEXT: ret float [[TMP1]]
; CHECK-NEXT: [[SUB:%.*]] = fmul reassoc nsz float [[X:%.*]], 6.000000e+00
; CHECK-NEXT: ret float [[SUB]]
;
%mul = fmul float %x, 7.0
%sub = fsub reassoc nsz float %mul, %x
@ -454,8 +454,7 @@ define float @fsub_op0_fmul_const(float %x) {
define <2 x float> @fsub_op0_fmul_const_vec(<2 x float> %x) {
; CHECK-LABEL: @fsub_op0_fmul_const_vec(
; CHECK-NEXT: [[MUL:%.*]] = fmul <2 x float> [[X:%.*]], <float 7.000000e+00, float -4.200000e+01>
; CHECK-NEXT: [[SUB:%.*]] = fsub reassoc nsz <2 x float> [[MUL]], [[X]]
; CHECK-NEXT: [[SUB:%.*]] = fmul reassoc nsz <2 x float> [[X:%.*]], <float 6.000000e+00, float -4.300000e+01>
; CHECK-NEXT: ret <2 x float> [[SUB]]
;
%mul = fmul <2 x float> %x, <float 7.0, float -42.0>
@ -467,8 +466,8 @@ define <2 x float> @fsub_op0_fmul_const_vec(<2 x float> %x) {
define float @fsub_op1_fmul_const(float %x) {
; CHECK-LABEL: @fsub_op1_fmul_const(
; CHECK-NEXT: [[TMP1:%.*]] = fmul reassoc nsz float [[X:%.*]], -6.000000e+00
; CHECK-NEXT: ret float [[TMP1]]
; CHECK-NEXT: [[SUB:%.*]] = fmul reassoc nsz float [[X:%.*]], -6.000000e+00
; CHECK-NEXT: ret float [[SUB]]
;
%mul = fmul float %x, 7.0
%sub = fsub reassoc nsz float %x, %mul
@ -479,8 +478,7 @@ define float @fsub_op1_fmul_const(float %x) {
define <2 x float> @fsub_op1_fmul_const_vec(<2 x float> %x) {
; CHECK-LABEL: @fsub_op1_fmul_const_vec(
; CHECK-NEXT: [[MUL:%.*]] = fmul <2 x float> [[X:%.*]], <float 7.000000e+00, float 0.000000e+00>
; CHECK-NEXT: [[SUB:%.*]] = fsub reassoc nsz <2 x float> [[X]], [[MUL]]
; CHECK-NEXT: [[SUB:%.*]] = fmul reassoc nsz <2 x float> [[X:%.*]], <float -6.000000e+00, float 1.000000e+00>
; CHECK-NEXT: ret <2 x float> [[SUB]]
;
%mul = fmul <2 x float> %x, <float 7.0, float 0.0>