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[InstCombine] handle trunc to i1 in foldLogOpOfMaskedICmps. #128861

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Merged
merged 1 commit into from
Apr 9, 2025
Merged

[InstCombine] handle trunc to i1 in foldLogOpOfMaskedICmps. #128861

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13 changes: 7 additions & 6 deletions llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3347,12 +3347,6 @@ Value *InstCombinerImpl::foldAndOrOfICmps(ICmpInst *LHS, ICmpInst *RHS,
}
}

// handle (roughly):
// (icmp ne (A & B), C) | (icmp ne (A & D), E)
// (icmp eq (A & B), C) & (icmp eq (A & D), E)
if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, IsAnd, IsLogical, Builder, Q))
return V;

if (Value *V =
foldAndOrOfICmpEqConstantAndICmp(LHS, RHS, IsAnd, IsLogical, Builder))
return V;
Expand Down Expand Up @@ -3527,6 +3521,13 @@ Value *InstCombinerImpl::foldBooleanAndOr(Value *LHS, Value *RHS,
if (!LHS->getType()->isIntOrIntVectorTy(1))
return nullptr;

// handle (roughly):
// (icmp ne (A & B), C) | (icmp ne (A & D), E)
// (icmp eq (A & B), C) & (icmp eq (A & D), E)
if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, IsAnd, IsLogical, Builder,
SQ.getWithInstruction(&I)))
return V;

if (auto *LHSCmp = dyn_cast<ICmpInst>(LHS))
if (auto *RHSCmp = dyn_cast<ICmpInst>(RHS))
if (Value *Res = foldAndOrOfICmps(LHSCmp, RHSCmp, I, IsAnd, IsLogical))
Expand Down
6 changes: 2 additions & 4 deletions llvm/test/Transforms/InstCombine/eq-of-parts.ll
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Expand Up @@ -1455,10 +1455,8 @@ define i1 @and_trunc_i1(i8 %a1, i8 %a2) {
define i1 @and_trunc_i1_wrong_const(i8 %a1, i8 %a2) {
; CHECK-LABEL: @and_trunc_i1_wrong_const(
; CHECK-NEXT: [[XOR:%.*]] = xor i8 [[A1:%.*]], [[A2:%.*]]
; CHECK-NEXT: [[CMP:%.*]] = icmp ult i8 [[XOR]], 4
; CHECK-NEXT: [[LOBIT:%.*]] = trunc i8 [[XOR]] to i1
; CHECK-NEXT: [[LOBIT_INV:%.*]] = xor i1 [[LOBIT]], true
; CHECK-NEXT: [[AND:%.*]] = and i1 [[CMP]], [[LOBIT_INV]]
; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[XOR]], -3
; CHECK-NEXT: [[AND:%.*]] = icmp eq i8 [[TMP1]], 0
; CHECK-NEXT: ret i1 [[AND]]
;
%xor = xor i8 %a1, %a2
Expand Down
15 changes: 6 additions & 9 deletions llvm/test/Transforms/InstCombine/onehot_merge.ll
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Expand Up @@ -1163,10 +1163,9 @@ define i1 @two_types_of_bittest(i8 %x, i8 %c) {
define i1 @trunc_bittest_and_icmp_bittest(i8 %x, i8 %c) {
; CHECK-LABEL: @trunc_bittest_and_icmp_bittest(
; CHECK-NEXT: [[T0:%.*]] = shl nuw i8 1, [[C:%.*]]
; CHECK-NEXT: [[TRUNC:%.*]] = trunc i8 [[X:%.*]] to i1
; CHECK-NEXT: [[AND:%.*]] = and i8 [[X]], [[T0]]
; CHECK-NEXT: [[ICMP2:%.*]] = icmp ne i8 [[AND]], 0
; CHECK-NEXT: [[RET:%.*]] = and i1 [[ICMP2]], [[TRUNC]]
; CHECK-NEXT: [[TMP1:%.*]] = or i8 [[T0]], 1
; CHECK-NEXT: [[TMP2:%.*]] = and i8 [[X:%.*]], [[TMP1]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[TMP2]], [[TMP1]]
; CHECK-NEXT: ret i1 [[RET]]
;
%t0 = shl i8 1, %c
Expand All @@ -1180,11 +1179,9 @@ define i1 @trunc_bittest_and_icmp_bittest(i8 %x, i8 %c) {
define i1 @trunc_bittest_or_icmp_bittest(i8 %x, i8 %c) {
; CHECK-LABEL: @trunc_bittest_or_icmp_bittest(
; CHECK-NEXT: [[T0:%.*]] = shl nuw i8 1, [[C:%.*]]
; CHECK-NEXT: [[TRUNC:%.*]] = trunc i8 [[X:%.*]] to i1
; CHECK-NEXT: [[AND:%.*]] = and i8 [[X]], [[T0]]
; CHECK-NEXT: [[ICMP2:%.*]] = icmp eq i8 [[AND]], 0
; CHECK-NEXT: [[NOT:%.*]] = xor i1 [[TRUNC]], true
; CHECK-NEXT: [[RET:%.*]] = or i1 [[ICMP2]], [[NOT]]
; CHECK-NEXT: [[TMP1:%.*]] = or i8 [[T0]], 1
; CHECK-NEXT: [[TMP2:%.*]] = and i8 [[X:%.*]], [[TMP1]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[TMP2]], [[TMP1]]
; CHECK-NEXT: ret i1 [[RET]]
;
%t0 = shl i8 1, %c
Expand Down
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