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[InstCombine] Fix FMF propagation in foldSelectIntoOp #114356

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Merged
merged 1 commit into from
Oct 31, 2024
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[InstCombine] Fix FMF propagation in foldSelectIntoOp #114356

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5 changes: 2 additions & 3 deletions llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -529,9 +529,6 @@ Instruction *InstCombinerImpl::foldSelectIntoOp(SelectInst &SI, Value *TrueVal,
if (!OpToFold)
return nullptr;

// TODO: We probably ought to revisit cases where the select and FP
// instructions have different flags and add tests to ensure the
// behaviour is correct.
FastMathFlags FMF;
if (isa<FPMathOperator>(&SI))
FMF = SI.getFastMathFlags();
Expand Down Expand Up @@ -564,6 +561,8 @@ Instruction *InstCombinerImpl::foldSelectIntoOp(SelectInst &SI, Value *TrueVal,
BinaryOperator *BO =
BinaryOperator::Create(TVI->getOpcode(), FalseVal, NewSel);
BO->copyIRFlags(TVI);
if (isa<FPMathOperator>(&SI))
BO->andIRFlags(NewSel);
Comment on lines 563 to +565
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@arsenm arsenm Oct 31, 2024

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This API is so clumsy.

We could preserve more value flags if the same operands appear in both instructions, but that's probably not worth the complexity

return BO;
};

Expand Down
18 changes: 9 additions & 9 deletions llvm/test/Transforms/InstCombine/fold-select-fmul-if-zero.ll
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Expand Up @@ -468,7 +468,7 @@ define float @fmul_by_var_if_0_oeq_zero_f32_nsz_fmul(float %x, float %y) {
; CHECK-LABEL: @fmul_by_var_if_0_oeq_zero_f32_nsz_fmul(
; CHECK-NEXT: [[X_IS_ZERO:%.*]] = fcmp oeq float [[X:%.*]], 0.000000e+00
; CHECK-NEXT: [[SCALED_X:%.*]] = select nnan i1 [[X_IS_ZERO]], float [[Y:%.*]], float 1.000000e+00
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nsz float [[X]], [[SCALED_X]]
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul float [[X]], [[SCALED_X]]
; CHECK-NEXT: ret float [[SCALED_IF_DENORMAL]]
;
%x.is.zero = fcmp oeq float %x, 0.0
Expand All @@ -482,7 +482,7 @@ define float @fmul_by_var_if_0_oeq_zero_f32_nsz_ninf_fmul(float %x, float %y) {
; CHECK-LABEL: @fmul_by_var_if_0_oeq_zero_f32_nsz_ninf_fmul(
; CHECK-NEXT: [[X_IS_ZERO:%.*]] = fcmp oeq float [[X:%.*]], 0.000000e+00
; CHECK-NEXT: [[SCALED_X:%.*]] = select nnan i1 [[X_IS_ZERO]], float [[Y:%.*]], float 1.000000e+00
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul ninf nsz float [[X]], [[SCALED_X]]
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul float [[X]], [[SCALED_X]]
; CHECK-NEXT: ret float [[SCALED_IF_DENORMAL]]
;
%x.is.zero = fcmp oeq float %x, 0.0
Expand All @@ -496,7 +496,7 @@ define float @fmul_by_var_if_0_oeq_zero_f32_nsz_nnan_fmul(float %x, float %y) {
; CHECK-LABEL: @fmul_by_var_if_0_oeq_zero_f32_nsz_nnan_fmul(
; CHECK-NEXT: [[X_IS_ZERO:%.*]] = fcmp oeq float [[X:%.*]], 0.000000e+00
; CHECK-NEXT: [[SCALED_X:%.*]] = select nnan i1 [[X_IS_ZERO]], float [[Y:%.*]], float 1.000000e+00
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nnan nsz float [[X]], [[SCALED_X]]
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nnan float [[X]], [[SCALED_X]]
; CHECK-NEXT: ret float [[SCALED_IF_DENORMAL]]
;
%x.is.zero = fcmp oeq float %x, 0.0
Expand All @@ -510,7 +510,7 @@ define float @fmul_by_var_if_0_oeq_zero_f32_nnan_ninf_fmul(float %x, float %y) {
; CHECK-LABEL: @fmul_by_var_if_0_oeq_zero_f32_nnan_ninf_fmul(
; CHECK-NEXT: [[X_IS_ZERO:%.*]] = fcmp oeq float [[X:%.*]], 0.000000e+00
; CHECK-NEXT: [[SCALED_X:%.*]] = select nnan i1 [[X_IS_ZERO]], float [[Y:%.*]], float 1.000000e+00
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nnan ninf float [[X]], [[SCALED_X]]
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nnan float [[X]], [[SCALED_X]]
; CHECK-NEXT: ret float [[SCALED_IF_DENORMAL]]
;
%x.is.zero = fcmp oeq float %x, 0.0
Expand Down Expand Up @@ -559,7 +559,7 @@ define float @fmul_by_var_if_0_oeq_zero_f32_fmul_nnan_ninf_nsz(float %x, float %
; CHECK-LABEL: @fmul_by_var_if_0_oeq_zero_f32_fmul_nnan_ninf_nsz(
; CHECK-NEXT: [[X_IS_ZERO:%.*]] = fcmp oeq float [[X:%.*]], 0.000000e+00
; CHECK-NEXT: [[SCALED_X:%.*]] = select nnan i1 [[X_IS_ZERO]], float [[Y:%.*]], float 1.000000e+00
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nnan ninf nsz float [[X]], [[SCALED_X]]
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nnan float [[X]], [[SCALED_X]]
; CHECK-NEXT: ret float [[SCALED_IF_DENORMAL]]
;
%x.is.zero = fcmp oeq float %x, 0.0
Expand All @@ -572,7 +572,7 @@ define float @fmul_by_var_if_0_oeq_zero_f32_fmul_nnan_ninf_nsz_commuted(float %x
; CHECK-LABEL: @fmul_by_var_if_0_oeq_zero_f32_fmul_nnan_ninf_nsz_commuted(
; CHECK-NEXT: [[X_IS_ZERO:%.*]] = fcmp oeq float [[X:%.*]], 0.000000e+00
; CHECK-NEXT: [[SCALED_X:%.*]] = select nnan i1 [[X_IS_ZERO]], float [[Y:%.*]], float 1.000000e+00
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nnan ninf nsz float [[X]], [[SCALED_X]]
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nnan float [[X]], [[SCALED_X]]
; CHECK-NEXT: ret float [[SCALED_IF_DENORMAL]]
;
%x.is.zero = fcmp oeq float %x, 0.0
Expand All @@ -586,7 +586,7 @@ define float @fmul_by_var_if_0_oeq_zero_f32_fmul_nnan_ninf_select_known_never_ne
; CHECK-LABEL: @fmul_by_var_if_0_oeq_zero_f32_fmul_nnan_ninf_select_known_never_negzero(
; CHECK-NEXT: [[X_IS_ZERO:%.*]] = fcmp oeq float [[X:%.*]], 0.000000e+00
; CHECK-NEXT: [[SCALED_X:%.*]] = select nnan i1 [[X_IS_ZERO]], float [[Y:%.*]], float 1.000000e+00
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nnan ninf float [[X]], [[SCALED_X]]
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nnan float [[X]], [[SCALED_X]]
; CHECK-NEXT: ret float [[SCALED_IF_DENORMAL]]
;
%x.is.zero = fcmp oeq float %x, 0.0
Expand All @@ -599,7 +599,7 @@ define float @fmul_by_var_if_0_oeq_zero_f32_fmul_nnan_ninf_select_known_never_ne
; CHECK-LABEL: @fmul_by_var_if_0_oeq_zero_f32_fmul_nnan_ninf_select_known_never_negzero_negsub(
; CHECK-NEXT: [[X_IS_ZERO:%.*]] = fcmp oeq float [[X:%.*]], 0.000000e+00
; CHECK-NEXT: [[SCALED_X:%.*]] = select nnan i1 [[X_IS_ZERO]], float [[Y:%.*]], float 1.000000e+00
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nnan ninf float [[X]], [[SCALED_X]]
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nnan float [[X]], [[SCALED_X]]
; CHECK-NEXT: ret float [[SCALED_IF_DENORMAL]]
;
%x.is.zero = fcmp oeq float %x, 0.0
Expand Down Expand Up @@ -706,7 +706,7 @@ define float @fmul_by_self_if_0_oeq_zero_f32_fmul_nnan_ninf_nsz(float %x) {
; CHECK-LABEL: @fmul_by_self_if_0_oeq_zero_f32_fmul_nnan_ninf_nsz(
; CHECK-NEXT: [[X_IS_ZERO:%.*]] = fcmp oeq float [[X:%.*]], 0.000000e+00
; CHECK-NEXT: [[SCALED_X:%.*]] = select nnan i1 [[X_IS_ZERO]], float [[X]], float 1.000000e+00
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nnan ninf nsz float [[X]], [[SCALED_X]]
; CHECK-NEXT: [[SCALED_IF_DENORMAL:%.*]] = fmul nnan float [[X]], [[SCALED_X]]
; CHECK-NEXT: ret float [[SCALED_IF_DENORMAL]]
;
%x.is.zero = fcmp oeq float %x, 0.0
Expand Down
16 changes: 8 additions & 8 deletions llvm/test/Transforms/InstCombine/select-binop-foldable-floating-point.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -48,7 +48,7 @@ define float @select_nnan_fadd_swapped(i1 %cond, float %A, float %B) {
define float @select_nnan_fadd_fast_math(i1 %cond, float %A, float %B) {
; CHECK-LABEL: @select_nnan_fadd_fast_math(
; CHECK-NEXT: [[C:%.*]] = select nnan i1 [[COND:%.*]], float [[B:%.*]], float -0.000000e+00
; CHECK-NEXT: [[D:%.*]] = fadd fast float [[A:%.*]], [[C]]
; CHECK-NEXT: [[D:%.*]] = fadd nnan float [[A:%.*]], [[C]]
; CHECK-NEXT: ret float [[D]]
;
%C = fadd fast float %A, %B
Expand All @@ -59,7 +59,7 @@ define float @select_nnan_fadd_fast_math(i1 %cond, float %A, float %B) {
define float @select_nnan_fadd_swapped_fast_math(i1 %cond, float %A, float %B) {
; CHECK-LABEL: @select_nnan_fadd_swapped_fast_math(
; CHECK-NEXT: [[C:%.*]] = select nnan i1 [[COND:%.*]], float -0.000000e+00, float [[B:%.*]]
; CHECK-NEXT: [[D:%.*]] = fadd fast float [[A:%.*]], [[C]]
; CHECK-NEXT: [[D:%.*]] = fadd nnan float [[A:%.*]], [[C]]
; CHECK-NEXT: ret float [[D]]
;
%C = fadd fast float %A, %B
Expand Down Expand Up @@ -125,7 +125,7 @@ define float @select_nnan_fmul_swapped(i1 %cond, float %A, float %B) {
define float @select_nnan_fmul_fast_math(i1 %cond, float %A, float %B) {
; CHECK-LABEL: @select_nnan_fmul_fast_math(
; CHECK-NEXT: [[C:%.*]] = select nnan i1 [[COND:%.*]], float [[B:%.*]], float 1.000000e+00
; CHECK-NEXT: [[D:%.*]] = fmul fast float [[A:%.*]], [[C]]
; CHECK-NEXT: [[D:%.*]] = fmul nnan float [[A:%.*]], [[C]]
; CHECK-NEXT: ret float [[D]]
;
%C = fmul fast float %A, %B
Expand All @@ -136,7 +136,7 @@ define float @select_nnan_fmul_fast_math(i1 %cond, float %A, float %B) {
define float @select_nnan_fmul_swapped_fast_math(i1 %cond, float %A, float %B) {
; CHECK-LABEL: @select_nnan_fmul_swapped_fast_math(
; CHECK-NEXT: [[C:%.*]] = select nnan i1 [[COND:%.*]], float 1.000000e+00, float [[B:%.*]]
; CHECK-NEXT: [[D:%.*]] = fmul fast float [[A:%.*]], [[C]]
; CHECK-NEXT: [[D:%.*]] = fmul nnan float [[A:%.*]], [[C]]
; CHECK-NEXT: ret float [[D]]
;
%C = fmul fast float %A, %B
Expand Down Expand Up @@ -169,7 +169,7 @@ define float @select_nnan_fsub_swapped(i1 %cond, float %A, float %B) {
define float @select_nnan_fsub_fast_math(i1 %cond, float %A, float %B) {
; CHECK-LABEL: @select_nnan_fsub_fast_math(
; CHECK-NEXT: [[C:%.*]] = select nnan i1 [[COND:%.*]], float [[B:%.*]], float 0.000000e+00
; CHECK-NEXT: [[D:%.*]] = fsub fast float [[A:%.*]], [[C]]
; CHECK-NEXT: [[D:%.*]] = fsub nnan float [[A:%.*]], [[C]]
; CHECK-NEXT: ret float [[D]]
;
%C = fsub fast float %A, %B
Expand All @@ -180,7 +180,7 @@ define float @select_nnan_fsub_fast_math(i1 %cond, float %A, float %B) {
define float @select_nnan_fsub_swapped_fast_math(i1 %cond, float %A, float %B) {
; CHECK-LABEL: @select_nnan_fsub_swapped_fast_math(
; CHECK-NEXT: [[C:%.*]] = select nnan i1 [[COND:%.*]], float 0.000000e+00, float [[B:%.*]]
; CHECK-NEXT: [[D:%.*]] = fsub fast float [[A:%.*]], [[C]]
; CHECK-NEXT: [[D:%.*]] = fsub nnan float [[A:%.*]], [[C]]
; CHECK-NEXT: ret float [[D]]
;
%C = fsub fast float %A, %B
Expand Down Expand Up @@ -247,7 +247,7 @@ define float @select_nnan_fdiv_swapped(i1 %cond, float %A, float %B) {
define float @select_nnan_fdiv_fast_math(i1 %cond, float %A, float %B) {
; CHECK-LABEL: @select_nnan_fdiv_fast_math(
; CHECK-NEXT: [[C:%.*]] = select nnan i1 [[COND:%.*]], float [[B:%.*]], float 1.000000e+00
; CHECK-NEXT: [[D:%.*]] = fdiv fast float [[A:%.*]], [[C]]
; CHECK-NEXT: [[D:%.*]] = fdiv nnan float [[A:%.*]], [[C]]
; CHECK-NEXT: ret float [[D]]
;
%C = fdiv fast float %A, %B
Expand All @@ -258,7 +258,7 @@ define float @select_nnan_fdiv_fast_math(i1 %cond, float %A, float %B) {
define float @select_nnan_fdiv_swapped_fast_math(i1 %cond, float %A, float %B) {
; CHECK-LABEL: @select_nnan_fdiv_swapped_fast_math(
; CHECK-NEXT: [[C:%.*]] = select nnan i1 [[COND:%.*]], float 1.000000e+00, float [[B:%.*]]
; CHECK-NEXT: [[D:%.*]] = fdiv fast float [[A:%.*]], [[C]]
; CHECK-NEXT: [[D:%.*]] = fdiv nnan float [[A:%.*]], [[C]]
; CHECK-NEXT: ret float [[D]]
;
%C = fdiv fast float %A, %B
Expand Down
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