Skip to content

[InstSimplify] Fold {u,s}{min,max} x, poison -> poison #138166

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
May 1, 2025
Merged

[InstSimplify] Fold {u,s}{min,max} x, poison -> poison #138166

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions llvm/lib/Analysis/InstructionSimplify.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -6549,6 +6549,10 @@ Value *llvm::simplifyBinaryIntrinsic(Intrinsic::ID IID, Type *ReturnType,
if (match(Op0, m_ImmConstant()))
std::swap(Op0, Op1);

// Propagate poison.
if (isa<PoisonValue>(Op1))
return Op1;

// Assume undef is the limit value.
if (Q.isUndefValue(Op1))
return ConstantInt::get(
Expand Down
8 changes: 4 additions & 4 deletions llvm/test/Transforms/InstSimplify/maxmin_intrinsics.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -75,7 +75,7 @@ define i81 @smax_undef(i81 %x) {

define i81 @smax_poison(i81 %x) {
; CHECK-LABEL: @smax_poison(
; CHECK-NEXT: ret i81 1208925819614629174706175
; CHECK-NEXT: ret i81 poison
;
%r = call i81 @llvm.smax.i81(i81 poison, i81 %x)
ret i81 %r
Expand All @@ -91,7 +91,7 @@ define i3 @smin_undef(i3 %x) {

define i3 @smin_poison(i3 %x) {
; CHECK-LABEL: @smin_poison(
; CHECK-NEXT: ret i3 -4
; CHECK-NEXT: ret i3 poison
;
%r = call i3 @llvm.smin.i3(i3 %x, i3 poison)
ret i3 %r
Expand All @@ -107,7 +107,7 @@ define <2 x i8> @umax_undef(<2 x i8> %x) {

define <2 x i8> @umax_poison(<2 x i8> %x) {
; CHECK-LABEL: @umax_poison(
; CHECK-NEXT: ret <2 x i8> splat (i8 -1)
; CHECK-NEXT: ret <2 x i8> poison
;
%r = call <2 x i8> @llvm.umax.v2i8(<2 x i8> poison, <2 x i8> %x)
ret <2 x i8> %r
Expand All @@ -123,7 +123,7 @@ define <2 x i8> @umin_undef(<2 x i8> %x) {

define <2 x i8> @umin_poison(<2 x i8> %x) {
; CHECK-LABEL: @umin_poison(
; CHECK-NEXT: ret <2 x i8> zeroinitializer
; CHECK-NEXT: ret <2 x i8> poison
;
%r = call <2 x i8> @llvm.umin.v2i8(<2 x i8> %x, <2 x i8> poison)
ret <2 x i8> %r
Expand Down