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[ValueTracking][GlobalISel] UCMP and SCMP cannot create undef or poison #154404

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Merged
merged 1 commit into from
Aug 19, 2025
Merged

[ValueTracking][GlobalISel] UCMP and SCMP cannot create undef or poison #154404

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2 changes: 2 additions & 0 deletions llvm/lib/Analysis/ValueTracking.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -7394,8 +7394,10 @@ static bool canCreateUndefOrPoison(const Operator *Op, UndefPoisonKind Kind,
case Intrinsic::fshr:
case Intrinsic::smax:
case Intrinsic::smin:
case Intrinsic::scmp:
case Intrinsic::umax:
case Intrinsic::umin:
case Intrinsic::ucmp:
case Intrinsic::ptrmask:
case Intrinsic::fptoui_sat:
case Intrinsic::fptosi_sat:
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2 changes: 2 additions & 0 deletions llvm/lib/CodeGen/GlobalISel/Utils.cpp
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Expand Up @@ -1869,8 +1869,10 @@ static bool canCreateUndefOrPoison(Register Reg, const MachineRegisterInfo &MRI,
case TargetOpcode::G_FSHR:
case TargetOpcode::G_SMAX:
case TargetOpcode::G_SMIN:
case TargetOpcode::G_SCMP:
case TargetOpcode::G_UMAX:
case TargetOpcode::G_UMIN:
case TargetOpcode::G_UCMP:
case TargetOpcode::G_PTRMASK:
case TargetOpcode::G_SADDO:
case TargetOpcode::G_SSUBO:
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34 changes: 34 additions & 0 deletions llvm/test/CodeGen/AArch64/freeze.ll
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Expand Up @@ -429,3 +429,37 @@ define <8 x i16> @freeze_abds(<8 x i16> %a, <8 x i16> %b) {
%r = add <8 x i16> %a, %f
ret <8 x i16> %r
}

define i32 @freeze_scmp(i32 %a0) nounwind {
; CHECK-LABEL: freeze_scmp:
; CHECK: // %bb.0:
; CHECK-NEXT: mov w8, #2 // =0x2
; CHECK-NEXT: cmp w8, w0
; CHECK-NEXT: cset w8, gt
; CHECK-NEXT: csinv w8, w8, wzr, ge
; CHECK-NEXT: cmp wzr, w8
; CHECK-NEXT: cset w8, gt
; CHECK-NEXT: csinv w0, w8, wzr, ge
; CHECK-NEXT: ret
%x = call i32 @llvm.scmp.i32(i32 2, i32 %a0)
%y = freeze i32 %x
%z = call i32 @llvm.scmp.i32(i32 0, i32 %y)
ret i32 %z
}

define i32 @freeze_ucmp(i32 %a0) nounwind {
; CHECK-LABEL: freeze_ucmp:
; CHECK: // %bb.0:
; CHECK-NEXT: mov w8, #2 // =0x2
; CHECK-NEXT: cmp w8, w0
; CHECK-NEXT: cset w8, hi
; CHECK-NEXT: csinv w8, w8, wzr, hs
; CHECK-NEXT: cmp w8, #1
; CHECK-NEXT: cset w8, hi
; CHECK-NEXT: csinv w0, w8, wzr, hs
; CHECK-NEXT: ret
%x = call i32 @llvm.ucmp.i32(i32 2, i32 %a0)
%y = freeze i32 %x
%z = call i32 @llvm.ucmp.i32(i32 %y, i32 1)
ret i32 %z
}
26 changes: 26 additions & 0 deletions llvm/test/Transforms/InstCombine/freeze-integer-intrinsics.ll
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Expand Up @@ -426,6 +426,32 @@ define i1 @widenable_condition() {
ret i1 %freeze
}

define i32 @freeze_scmp(i32 %a0) {
; CHECK-LABEL: @freeze_scmp(
; CHECK-NEXT: [[A0_FR:%.*]] = freeze i32 [[A0:%.*]]
; CHECK-NEXT: [[X:%.*]] = call i32 @llvm.scmp.i32.i32(i32 2, i32 [[A0_FR]])
; CHECK-NEXT: [[Z:%.*]] = call i32 @llvm.scmp.i32.i32(i32 0, i32 [[X]])
; CHECK-NEXT: ret i32 [[Z]]
;
%x = call i32 @llvm.scmp.i32(i32 2, i32 %a0)
%y = freeze i32 %x
%z = call i32 @llvm.scmp.i32(i32 0, i32 %y)
ret i32 %z
}

define i32 @freeze_ucmp(i32 %a0) {
; CHECK-LABEL: @freeze_ucmp(
; CHECK-NEXT: [[A0_FR:%.*]] = freeze i32 [[A0:%.*]]
; CHECK-NEXT: [[X:%.*]] = call i32 @llvm.ucmp.i32.i32(i32 2, i32 [[A0_FR]])
; CHECK-NEXT: [[Z:%.*]] = call i32 @llvm.ucmp.i32.i32(i32 [[X]], i32 1)
; CHECK-NEXT: ret i32 [[Z]]
;
%x = call i32 @llvm.ucmp.i32(i32 2, i32 %a0)
%y = freeze i32 %x
%z = call i32 @llvm.ucmp.i32(i32 %y, i32 1)
ret i32 %z
}

declare i32 @llvm.ctlz.i32(i32, i1 immarg)
declare i32 @llvm.cttz.i32(i32, i1 immarg)
declare i32 @llvm.abs.i32(i32, i1 immarg)
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