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Revert "[InstCombine] Folding (icmp eq/ne (and X, -P2), INT_MIN)" #111236

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Merged
merged 1 commit into from
Oct 5, 2024
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Revert "[InstCombine] Folding (icmp eq/ne (and X, -P2), INT_MIN)" #111236

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12 changes: 0 additions & 12 deletions llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5015,18 +5015,6 @@ Instruction *InstCombinerImpl::foldICmpBinOp(ICmpInst &I,
}
}

// (icmp eq/ne (X, -P2), INT_MIN)
// -> (icmp slt/sge X, INT_MIN + P2)
if (ICmpInst::isEquality(Pred) && BO0 &&
match(I.getOperand(1), m_SignMask()) &&
match(BO0, m_And(m_Value(), m_NegatedPower2OrZero()))) {
// Will Constant fold.
Value *NewC = Builder.CreateSub(I.getOperand(1), BO0->getOperand(1));
return new ICmpInst(Pred == ICmpInst::ICMP_EQ ? ICmpInst::ICMP_SLT
: ICmpInst::ICMP_SGE,
BO0->getOperand(0), NewC);
}

{
// Similar to above: an unsigned overflow comparison may use offset + mask:
// ((Op1 + C) & C) u< Op1 --> Op1 != 0
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9 changes: 6 additions & 3 deletions llvm/test/Transforms/InstCombine/icmp-signmask.ll
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Expand Up @@ -3,7 +3,8 @@

define i1 @cmp_x_and_negp2_with_eq(i8 %x) {
; CHECK-LABEL: @cmp_x_and_negp2_with_eq(
; CHECK-NEXT: [[R:%.*]] = icmp slt i8 [[X:%.*]], -126
; CHECK-NEXT: [[ANDX:%.*]] = and i8 [[X:%.*]], -2
; CHECK-NEXT: [[R:%.*]] = icmp eq i8 [[ANDX]], -128
; CHECK-NEXT: ret i1 [[R]]
;
%andx = and i8 %x, -2
Expand All @@ -24,7 +25,8 @@ define i1 @cmp_x_and_negp2_with_eq_fail_not_signmask(i8 %x) {

define <2 x i1> @cmp_x_and_negp2_with_ne(<2 x i8> %x) {
; CHECK-LABEL: @cmp_x_and_negp2_with_ne(
; CHECK-NEXT: [[R:%.*]] = icmp sgt <2 x i8> [[X:%.*]], <i8 -121, i8 -113>
; CHECK-NEXT: [[ANDX:%.*]] = and <2 x i8> [[X:%.*]], <i8 -8, i8 -16>
; CHECK-NEXT: [[R:%.*]] = icmp ne <2 x i8> [[ANDX]], <i8 -128, i8 -128>
; CHECK-NEXT: ret <2 x i1> [[R]]
;
%andx = and <2 x i8> %x, <i8 -8, i8 -16>
Expand All @@ -34,7 +36,8 @@ define <2 x i1> @cmp_x_and_negp2_with_ne(<2 x i8> %x) {

define <2 x i1> @cmp_x_and_negp2_with_ne_or_z(<2 x i8> %x) {
; CHECK-LABEL: @cmp_x_and_negp2_with_ne_or_z(
; CHECK-NEXT: [[R:%.*]] = icmp sge <2 x i8> [[X:%.*]], <i8 -128, i8 -112>
; CHECK-NEXT: [[ANDX:%.*]] = and <2 x i8> [[X:%.*]], <i8 0, i8 -16>
; CHECK-NEXT: [[R:%.*]] = icmp ne <2 x i8> [[ANDX]], <i8 -128, i8 -128>
; CHECK-NEXT: ret <2 x i1> [[R]]
;
%andx = and <2 x i8> %x, <i8 0, i8 -16>
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3 changes: 2 additions & 1 deletion llvm/test/Transforms/InstCombine/icmp.ll
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Expand Up @@ -1116,7 +1116,8 @@ define i1 @test53(i32 %a, i32 %b) {

define i1 @test54(i8 %a) {
; CHECK-LABEL: @test54(
; CHECK-NEXT: [[RET:%.*]] = icmp slt i8 [[A:%.*]], -64
; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[A:%.*]], -64
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[TMP1]], -128
; CHECK-NEXT: ret i1 [[RET]]
;
%ext = zext i8 %a to i32
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