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[InstCombine] Propagate poison pow[i], [us]add, [us]sub and [us]mul #146750

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Merged
merged 8 commits into from
Jul 4, 2025
Merged

[InstCombine] Propagate poison pow[i], [us]add, [us]sub and [us]mul #146750

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61d05be
Precommit missed opt for pow poison
Jul 2, 2025
a67e87e
[InstCombine] Fold poison pow to poison
Jul 2, 2025
1da97c9
Refactor support for pow[i] poison folding
Jul 3, 2025
69771ea
Fix naming nits from PR
Jul 3, 2025
251bfa3
Remove old one off cse of poison folding
Jul 3, 2025
e08eb3f
Added vector support for pow[i] poison
Jul 3, 2025
d2244eb
Update unittest for pow[i] poison
Jul 3, 2025
413adc0
Remove case comments for intrinsics poison
Jul 4, 2025
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3 changes: 3 additions & 0 deletions llvm/lib/Analysis/InstructionSimplify.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -6793,6 +6793,9 @@ static Value *simplifyIntrinsic(CallBase *Call, Value *Callee,
Function *F = cast<Function>(Callee);
Intrinsic::ID IID = F->getIntrinsicID();

if (IID != Intrinsic::not_intrinsic && intrinsicPropagatesPoison(IID) &&
any_of(Args, IsaPred<PoisonValue>))
return PoisonValue::get(F->getReturnType());
// Most of the intrinsics with no operands have some kind of side effect.
// Don't simplify.
if (!NumOperands) {
Expand Down
2 changes: 2 additions & 0 deletions llvm/lib/Analysis/ValueTracking.cpp
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Expand Up @@ -7912,6 +7912,8 @@ bool llvm::intrinsicPropagatesPoison(Intrinsic::ID IID) {
case Intrinsic::ushl_sat:
case Intrinsic::smul_fix:
case Intrinsic::smul_fix_sat:
case Intrinsic::pow:
case Intrinsic::powi:
case Intrinsic::canonicalize:
case Intrinsic::sqrt:
return true;
Expand Down
24 changes: 12 additions & 12 deletions llvm/test/Transforms/InstSimplify/call.ll
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Expand Up @@ -36,7 +36,7 @@ define {i8, i1} @test_uadd3(i8 %v) {

define {i8, i1} @test_uadd3_poison(i8 %v) {
; CHECK-LABEL: @test_uadd3_poison(
; CHECK-NEXT: ret { i8, i1 } { i8 -1, i1 false }
; CHECK-NEXT: ret { i8, i1 } poison
;
%result = call {i8, i1} @llvm.uadd.with.overflow.i8(i8 %v, i8 poison)
ret {i8, i1} %result
Expand All @@ -52,7 +52,7 @@ define {i8, i1} @test_uadd4(i8 %v) {

define {i8, i1} @test_uadd4_poison(i8 %v) {
; CHECK-LABEL: @test_uadd4_poison(
; CHECK-NEXT: ret { i8, i1 } { i8 -1, i1 false }
; CHECK-NEXT: ret { i8, i1 } poison
;
%result = call {i8, i1} @llvm.uadd.with.overflow.i8(i8 poison, i8 %v)
ret {i8, i1} %result
Expand Down Expand Up @@ -86,7 +86,7 @@ define {i8, i1} @test_sadd3(i8 %v) {

define {i8, i1} @test_sadd3_poison(i8 %v) {
; CHECK-LABEL: @test_sadd3_poison(
; CHECK-NEXT: ret { i8, i1 } { i8 -1, i1 false }
; CHECK-NEXT: ret { i8, i1 } poison
;
%result = call {i8, i1} @llvm.sadd.with.overflow.i8(i8 %v, i8 poison)
ret {i8, i1} %result
Expand All @@ -102,7 +102,7 @@ define {i8, i1} @test_sadd4(i8 %v) {

define {i8, i1} @test_sadd4_poison(i8 %v) {
; CHECK-LABEL: @test_sadd4_poison(
; CHECK-NEXT: ret { i8, i1 } { i8 -1, i1 false }
; CHECK-NEXT: ret { i8, i1 } poison
;
%result = call {i8, i1} @llvm.sadd.with.overflow.i8(i8 poison, i8 %v)
ret {i8, i1} %result
Expand All @@ -126,7 +126,7 @@ define {i8, i1} @test_usub2(i8 %V) {

define {i8, i1} @test_usub2_poison(i8 %V) {
; CHECK-LABEL: @test_usub2_poison(
; CHECK-NEXT: ret { i8, i1 } zeroinitializer
; CHECK-NEXT: ret { i8, i1 } poison
;
%x = call {i8, i1} @llvm.usub.with.overflow.i8(i8 %V, i8 poison)
ret {i8, i1} %x
Expand All @@ -142,7 +142,7 @@ define {i8, i1} @test_usub3(i8 %V) {

define {i8, i1} @test_usub3_poison(i8 %V) {
; CHECK-LABEL: @test_usub3_poison(
; CHECK-NEXT: ret { i8, i1 } zeroinitializer
; CHECK-NEXT: ret { i8, i1 } poison
;
%x = call {i8, i1} @llvm.usub.with.overflow.i8(i8 poison, i8 %V)
ret {i8, i1} %x
Expand All @@ -166,7 +166,7 @@ define {i8, i1} @test_ssub2(i8 %V) {

define {i8, i1} @test_ssub2_poison(i8 %V) {
; CHECK-LABEL: @test_ssub2_poison(
; CHECK-NEXT: ret { i8, i1 } zeroinitializer
; CHECK-NEXT: ret { i8, i1 } poison
;
%x = call {i8, i1} @llvm.ssub.with.overflow.i8(i8 %V, i8 poison)
ret {i8, i1} %x
Expand All @@ -182,7 +182,7 @@ define {i8, i1} @test_ssub3(i8 %V) {

define {i8, i1} @test_ssub3_poison(i8 %V) {
; CHECK-LABEL: @test_ssub3_poison(
; CHECK-NEXT: ret { i8, i1 } zeroinitializer
; CHECK-NEXT: ret { i8, i1 } poison
;
%x = call {i8, i1} @llvm.ssub.with.overflow.i8(i8 poison, i8 %V)
ret {i8, i1} %x
Expand All @@ -206,7 +206,7 @@ define {i8, i1} @test_umul2(i8 %V) {

define {i8, i1} @test_umul2_poison(i8 %V) {
; CHECK-LABEL: @test_umul2_poison(
; CHECK-NEXT: ret { i8, i1 } zeroinitializer
; CHECK-NEXT: ret { i8, i1 } poison
;
%x = call {i8, i1} @llvm.umul.with.overflow.i8(i8 %V, i8 poison)
ret {i8, i1} %x
Expand All @@ -230,7 +230,7 @@ define {i8, i1} @test_umul4(i8 %V) {

define {i8, i1} @test_umul4_poison(i8 %V) {
; CHECK-LABEL: @test_umul4_poison(
; CHECK-NEXT: ret { i8, i1 } zeroinitializer
; CHECK-NEXT: ret { i8, i1 } poison
;
%x = call {i8, i1} @llvm.umul.with.overflow.i8(i8 poison, i8 %V)
ret {i8, i1} %x
Expand All @@ -254,7 +254,7 @@ define {i8, i1} @test_smul2(i8 %V) {

define {i8, i1} @test_smul2_poison(i8 %V) {
; CHECK-LABEL: @test_smul2_poison(
; CHECK-NEXT: ret { i8, i1 } zeroinitializer
; CHECK-NEXT: ret { i8, i1 } poison
;
%x = call {i8, i1} @llvm.smul.with.overflow.i8(i8 %V, i8 poison)
ret {i8, i1} %x
Expand All @@ -278,7 +278,7 @@ define {i8, i1} @test_smul4(i8 %V) {

define {i8, i1} @test_smul4_poison(i8 %V) {
; CHECK-LABEL: @test_smul4_poison(
; CHECK-NEXT: ret { i8, i1 } zeroinitializer
; CHECK-NEXT: ret { i8, i1 } poison
;
%x = call {i8, i1} @llvm.smul.with.overflow.i8(i8 poison, i8 %V)
ret {i8, i1} %x
Expand Down
37 changes: 36 additions & 1 deletion llvm/test/Transforms/InstSimplify/fold-intrinsics.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,7 @@ define void @powi(double %V, ptr%P) {
define void @powi_i16(float %V, ptr%P) {
; CHECK-LABEL: @powi_i16(
; CHECK-NEXT: store volatile float 1.000000e+00, ptr [[P:%.*]], align 4
; CHECK-NEXT: store volatile float [[V:%.*]], ptr [[P]], align 4
; CHECK-NEXT: store volatile float [[D:%.*]], ptr [[P]], align 4
; CHECK-NEXT: ret void
;
%B = tail call float @llvm.powi.f32.i16(float %V, i16 0) nounwind
Expand All @@ -52,3 +52,38 @@ define i32 @test_ctpop_poison(i32 %a) {
%res = tail call i32 @llvm.ctpop.i32(i32 poison)
ret i32 %res
}

define void @pow_poison(i16 %arg_int,float %arg_flt, ptr %P) {
; CHECK-LABEL: @pow_poison(
; CHECK-NEXT: store volatile float poison, ptr [[P:%.*]], align 4
; CHECK-NEXT: store volatile float poison, ptr [[P]], align 4
; CHECK-NEXT: store volatile float poison, ptr [[P]], align 4
; CHECK-NEXT: store volatile float poison, ptr [[P]], align 4
; CHECK-NEXT: store volatile float poison, ptr [[P]], align 4
; CHECK-NEXT: store volatile float poison, ptr [[P]], align 4
; CHECK-NEXT: store volatile <2 x float> poison, ptr [[P]], align 8
; CHECK-NEXT: ret void
;
%2 = tail call float @llvm.powi(float poison, i16 %arg_int) nounwind
store volatile float %2, ptr %P

%3 = tail call float @llvm.pow(float poison, float %arg_flt) nounwind
store volatile float %3, ptr %P

%4 = tail call float @llvm.powi(float %arg_flt, i16 poison) nounwind
store volatile float %4, ptr %P

%5 = tail call float @llvm.pow(float %arg_flt, float poison) nounwind
store volatile float %5, ptr %P

%6 = tail call float @llvm.powi(float poison, i16 poison) nounwind
store volatile float %6, ptr %P

%7 = tail call float @llvm.pow(float poison, float poison) nounwind
store volatile float %7, ptr %P

%8 = tail call <2 x float> @llvm.pow(<2 x float> poison, <2 x float> poison) nounwind
store volatile <2 x float> %8, ptr %P

ret void
}
32 changes: 16 additions & 16 deletions llvm/test/Transforms/InstSimplify/saturating-add-sub.ll
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Expand Up @@ -90,7 +90,7 @@ define i8 @uadd_scalar_undef(i8 %a) {

define i8 @uadd_scalar_poison(i8 %a) {
; CHECK-LABEL: @uadd_scalar_poison(
; CHECK-NEXT: ret i8 -1
; CHECK-NEXT: ret i8 poison
;
%x5 = call i8 @llvm.uadd.sat.i8(i8 %a, i8 poison)
ret i8 %x5
Expand All @@ -106,7 +106,7 @@ define <2 x i8> @uadd_vector_undef(<2 x i8> %a) {

define <2 x i8> @uadd_vector_poison(<2 x i8> %a) {
; CHECK-LABEL: @uadd_vector_poison(
; CHECK-NEXT: ret <2 x i8> splat (i8 -1)
; CHECK-NEXT: ret <2 x i8> poison
;
%x5v = call <2 x i8> @llvm.uadd.sat.v2i8(<2 x i8> %a, <2 x i8> <i8 poison, i8 poison>)
ret <2 x i8> %x5v
Expand All @@ -122,7 +122,7 @@ define i8 @uadd_scalar_undef_commute(i8 %a) {

define i8 @uadd_scalar_poison_commute(i8 %a) {
; CHECK-LABEL: @uadd_scalar_poison_commute(
; CHECK-NEXT: ret i8 -1
; CHECK-NEXT: ret i8 poison
;
%x6 = call i8 @llvm.uadd.sat.i8(i8 poison, i8 %a)
ret i8 %x6
Expand All @@ -138,7 +138,7 @@ define <2 x i8> @uadd_vector_undef_commute(<2 x i8> %a) {

define <2 x i8> @uadd_vector_poison_commute(<2 x i8> %a) {
; CHECK-LABEL: @uadd_vector_poison_commute(
; CHECK-NEXT: ret <2 x i8> splat (i8 -1)
; CHECK-NEXT: ret <2 x i8> poison
;
%x5v = call <2 x i8> @llvm.uadd.sat.v2i8(<2 x i8> poison, <2 x i8> %a)
ret <2 x i8> %x5v
Expand Down Expand Up @@ -222,7 +222,7 @@ define i8 @sadd_scalar_undef(i8 %a) {

define i8 @sadd_scalar_poison(i8 %a) {
; CHECK-LABEL: @sadd_scalar_poison(
; CHECK-NEXT: ret i8 -1
; CHECK-NEXT: ret i8 poison
;
%y5 = call i8 @llvm.sadd.sat.i8(i8 %a, i8 poison)
ret i8 %y5
Expand All @@ -238,7 +238,7 @@ define <2 x i8> @sadd_vector_undef(<2 x i8> %a) {

define <2 x i8> @sadd_vector_poison(<2 x i8> %a) {
; CHECK-LABEL: @sadd_vector_poison(
; CHECK-NEXT: ret <2 x i8> splat (i8 -1)
; CHECK-NEXT: ret <2 x i8> poison
;
%y5v = call <2 x i8> @llvm.sadd.sat.v2i8(<2 x i8> %a, <2 x i8> poison)
ret <2 x i8> %y5v
Expand All @@ -254,7 +254,7 @@ define i8 @sadd_scalar_undef_commute(i8 %a) {

define i8 @sadd_scalar_poison_commute(i8 %a) {
; CHECK-LABEL: @sadd_scalar_poison_commute(
; CHECK-NEXT: ret i8 -1
; CHECK-NEXT: ret i8 poison
;
%y6 = call i8 @llvm.sadd.sat.i8(i8 poison, i8 %a)
ret i8 %y6
Expand All @@ -270,7 +270,7 @@ define <2 x i8> @sadd_vector_undef_commute(<2 x i8> %a) {

define <2 x i8> @sadd_vector_poison_commute(<2 x i8> %a) {
; CHECK-LABEL: @sadd_vector_poison_commute(
; CHECK-NEXT: ret <2 x i8> splat (i8 -1)
; CHECK-NEXT: ret <2 x i8> poison
;
%y6v = call <2 x i8> @llvm.sadd.sat.v2i8(<2 x i8> poison, <2 x i8> %a)
ret <2 x i8> %y6v
Expand Down Expand Up @@ -334,7 +334,7 @@ define i8 @usub_scalar_undef(i8 %a) {

define i8 @usub_scalar_poison(i8 %a) {
; CHECK-LABEL: @usub_scalar_poison(
; CHECK-NEXT: ret i8 0
; CHECK-NEXT: ret i8 poison
;
%x4 = call i8 @llvm.usub.sat.i8(i8 %a, i8 poison)
ret i8 %x4
Expand All @@ -350,7 +350,7 @@ define <2 x i8> @usub_vector_undef(<2 x i8> %a) {

define <2 x i8> @usub_vector_poison(<2 x i8> %a) {
; CHECK-LABEL: @usub_vector_poison(
; CHECK-NEXT: ret <2 x i8> zeroinitializer
; CHECK-NEXT: ret <2 x i8> poison
;
%x4v = call <2 x i8> @llvm.usub.sat.v2i8(<2 x i8> %a, <2 x i8> <i8 poison, i8 poison>)
ret <2 x i8> %x4v
Expand All @@ -366,7 +366,7 @@ define i8 @usub_scalar_undef_commute(i8 %a) {

define i8 @usub_scalar_poison_commute(i8 %a) {
; CHECK-LABEL: @usub_scalar_poison_commute(
; CHECK-NEXT: ret i8 0
; CHECK-NEXT: ret i8 poison
;
%x5 = call i8 @llvm.usub.sat.i8(i8 poison, i8 %a)
ret i8 %x5
Expand All @@ -382,7 +382,7 @@ define <2 x i8> @usub_vector_undef_commute(<2 x i8> %a) {

define <2 x i8> @usub_vector_poison_commute(<2 x i8> %a) {
; CHECK-LABEL: @usub_vector_poison_commute(
; CHECK-NEXT: ret <2 x i8> zeroinitializer
; CHECK-NEXT: ret <2 x i8> poison
;
%x5v = call <2 x i8> @llvm.usub.sat.v2i8(<2 x i8> <i8 poison, i8 poison>, <2 x i8> %a)
ret <2 x i8> %x5v
Expand Down Expand Up @@ -466,7 +466,7 @@ define i8 @ssub_scalar_undef(i8 %a) {

define i8 @ssub_scalar_poison(i8 %a) {
; CHECK-LABEL: @ssub_scalar_poison(
; CHECK-NEXT: ret i8 0
; CHECK-NEXT: ret i8 poison
;
%y4 = call i8 @llvm.ssub.sat.i8(i8 %a, i8 poison)
ret i8 %y4
Expand All @@ -482,7 +482,7 @@ define <2 x i8> @ssub_vector_undef(<2 x i8> %a) {

define <2 x i8> @ssub_vector_poison(<2 x i8> %a) {
; CHECK-LABEL: @ssub_vector_poison(
; CHECK-NEXT: ret <2 x i8> zeroinitializer
; CHECK-NEXT: ret <2 x i8> poison
;
%y4v = call <2 x i8> @llvm.ssub.sat.v2i8(<2 x i8> %a, <2 x i8> poison)
ret <2 x i8> %y4v
Expand All @@ -498,7 +498,7 @@ define i8 @ssub_scalar_undef_commute(i8 %a) {

define i8 @ssub_scalar_poison_commute(i8 %a) {
; CHECK-LABEL: @ssub_scalar_poison_commute(
; CHECK-NEXT: ret i8 0
; CHECK-NEXT: ret i8 poison
;
%y5 = call i8 @llvm.ssub.sat.i8(i8 poison, i8 %a)
ret i8 %y5
Expand All @@ -514,7 +514,7 @@ define <2 x i8> @ssub_vector_undef_commute(<2 x i8> %a) {

define <2 x i8> @ssub_vector_poison_commute(<2 x i8> %a) {
; CHECK-LABEL: @ssub_vector_poison_commute(
; CHECK-NEXT: ret <2 x i8> zeroinitializer
; CHECK-NEXT: ret <2 x i8> poison
;
%y5v = call <2 x i8> @llvm.ssub.sat.v2i8(<2 x i8> <i8 poison, i8 poison>, <2 x i8> %a)
ret <2 x i8> %y5v
Expand Down
4 changes: 2 additions & 2 deletions llvm/unittests/Analysis/ValueTrackingTest.cpp
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Expand Up @@ -911,10 +911,10 @@ TEST(ValueTracking, propagatesPoison) {
{false, "call i32 @llvm.fshr.i32(i32 %x, i32 %y, i32 %shamt)", 1},
{false, "call i32 @llvm.fshr.i32(i32 %x, i32 %y, i32 %shamt)", 2},
{true, "call float @llvm.sqrt.f32(float %fx)", 0},
{false, "call float @llvm.powi.f32.i32(float %fx, i32 %x)", 0},
{true, "call float @llvm.powi.f32.i32(float %fx, i32 %x)", 0},
{false, "call float @llvm.sin.f32(float %fx)", 0},
{false, "call float @llvm.cos.f32(float %fx)", 0},
{false, "call float @llvm.pow.f32(float %fx, float %fy)", 0},
{true, "call float @llvm.pow.f32(float %fx, float %fy)", 0},
{false, "call float @llvm.exp.f32(float %fx)", 0},
{false, "call float @llvm.exp2.f32(float %fx)", 0},
{false, "call float @llvm.log.f32(float %fx)", 0},
Expand Down