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[InstCombine] Fold (trunc X to i1) & !iszero(X & Pow2)) -> (X & (1 | Pow2)) == (1 | Pow2) #119196

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[InstCombine] Fold (trunc X to i1) & !iszero(X & Pow2)) -> (X & (1 | Pow2)) == (1 | Pow2) #119196

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f73635a
[NFC] Pre-commit test Fold not(trunc X to i1) | iszero(X & Pow2) -> (…
andjo403 Dec 8, 2024
b0c724b
[InstCombine] Fold not(trunc X to i1) | iszero(X & Pow2) -> (X & (1 |…
andjo403 Dec 8, 2024
266fac9
[NFC] Add test for redundant freeze
andjo403 Dec 14, 2024
b781ca8
[InstCombine] remove redundant freeze in foldTruncAndOrICmpOfAndWithPow2
andjo403 Dec 14, 2024
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41 changes: 41 additions & 0 deletions llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -805,6 +805,43 @@ Value *InstCombinerImpl::foldAndOrOfICmpsOfAndWithPow2(ICmpInst *LHS,
return nullptr;
}

// Fold not(trunc X to i1) | iszero(X & Pow2)
// -> (X & (1 | Pow2)) != (1 | Pow2)
// Fold (trunc X to i1) & !iszero(X & Pow2))
// -> (X & (1 | Pow2)) == (1 | Pow2)
static Value *foldTruncAndOrICmpOfAndWithPow2(InstCombiner::BuilderTy &Builder,
Value *LHS, Value *RHS,
bool IsAnd, bool IsLogical,
const SimplifyQuery &Q) {
CmpInst::Predicate Pred = IsAnd ? CmpInst::ICMP_NE : CmpInst::ICMP_EQ;

bool Swapped = false;
if (isa<ICmpInst>(LHS)) {
std::swap(LHS, RHS);
Swapped = true;
}

Value *X, *Pow2;

if ((IsAnd ? match(LHS, m_Trunc(m_Value(X)))
: match(LHS, m_Not(m_Trunc(m_Value(X))))) &&
match(RHS, m_SpecificICmp(Pred, m_c_And(m_Specific(X), m_Value(Pow2)),
m_ZeroInt())) &&
isKnownToBeAPowerOfTwo(Pow2, Q.DL, /*OrZero=*/false, /*Depth=*/0, Q.AC,
Q.CxtI, Q.DT)) {
// If this is a logical and/or, then we must prevent propagation of a
// poison value from the RHS by inserting freeze.
if (!Swapped && IsLogical)
Pow2 = Builder.CreateFreeze(Pow2);
Value *Mask = Builder.CreateOr(ConstantInt::get(Pow2->getType(), 1), Pow2);
Value *Masked = Builder.CreateAnd(X, Mask);
auto NewPred = IsAnd ? CmpInst::ICMP_EQ : CmpInst::ICMP_NE;
return Builder.CreateICmp(NewPred, Masked, Mask);
}

return nullptr;
}

/// General pattern:
/// X & Y
///
Expand Down Expand Up @@ -3541,6 +3578,10 @@ Value *InstCombinerImpl::foldBooleanAndOr(Value *LHS, Value *RHS,

if (Value *Res = foldEqOfParts(LHS, RHS, IsAnd))
return Res;
const SimplifyQuery Q = SQ.getWithInstruction(&I);
if (Value *Res = foldTruncAndOrICmpOfAndWithPow2(Builder, LHS, RHS, IsAnd,
IsLogical, Q))
return Res;

return nullptr;
}
Expand Down
312 changes: 312 additions & 0 deletions llvm/test/Transforms/InstCombine/onehot_merge.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -1143,3 +1143,315 @@ define i1 @foo1_and_signbit_lshr_without_shifting_signbit_not_pwr2_logical(i32 %
%or = select i1 %t2, i1 true, i1 %t4
ret i1 %or
}

define i1 @trunc_or_icmp_consts(i8 %k) {
; CHECK-LABEL: @trunc_or_icmp_consts(
; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[K:%.*]], 9
; CHECK-NEXT: [[OR:%.*]] = icmp ne i8 [[TMP1]], 9
; CHECK-NEXT: ret i1 [[OR]]
;
%trunc = trunc i8 %k to i1
%not = xor i1 %trunc, true
%and = and i8 %k, 8
%icmp = icmp eq i8 %and, 0
%ret = or i1 %not, %icmp
ret i1 %ret
}

define i1 @icmp_or_trunc_consts(i8 %k) {
; CHECK-LABEL: @icmp_or_trunc_consts(
; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[K:%.*]], 9
; CHECK-NEXT: [[OR:%.*]] = icmp ne i8 [[TMP1]], 9
; CHECK-NEXT: ret i1 [[OR]]
;
%trunc = trunc i8 %k to i1
%not = xor i1 %trunc, true
%and = and i8 %k, 8
%icmp = icmp eq i8 %and, 0
%ret = or i1 %icmp, %not
ret i1 %ret
}

define i1 @trunc_or_icmp(i8 %k, i8 %c1) {
; CHECK-LABEL: @trunc_or_icmp(
; CHECK-NEXT: [[T:%.*]] = shl nuw i8 1, [[C1:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = or i8 [[T]], 1
; CHECK-NEXT: [[TMP2:%.*]] = and i8 [[K:%.*]], [[TMP1]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[TMP2]], [[TMP1]]
; CHECK-NEXT: ret i1 [[RET]]
;
%t = shl i8 1, %c1
%t1 = and i8 %t, %k
%icmp = icmp eq i8 %t1, 0
%trunc = trunc i8 %k to i1
%not = xor i1 %trunc, true
%ret = or i1 %icmp, %not
ret i1 %ret
}

define i1 @trunc_logical_or_icmp(i8 %k, i8 %c1) {
; CHECK-LABEL: @trunc_logical_or_icmp(
; CHECK-NEXT: [[T:%.*]] = shl nuw i8 1, [[C1:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = or i8 [[T]], 1
; CHECK-NEXT: [[TMP2:%.*]] = and i8 [[K:%.*]], [[TMP1]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[TMP2]], [[TMP1]]
; CHECK-NEXT: ret i1 [[RET]]
;
%t = shl i8 1, %c1
%t1 = and i8 %t, %k
%icmp = icmp eq i8 %t1, 0
%trunc = trunc i8 %k to i1
%not = xor i1 %trunc, true
%ret = select i1 %icmp, i1 true, i1 %not
ret i1 %ret
}

define i1 @icmp_logical_or_trunc(i8 %k, i8 %c1) {
; CHECK-LABEL: @icmp_logical_or_trunc(
; CHECK-NEXT: [[T:%.*]] = shl nuw i8 1, [[C1:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = freeze i8 [[T]]
; CHECK-NEXT: [[TMP2:%.*]] = or i8 [[TMP1]], 1
; CHECK-NEXT: [[TMP3:%.*]] = and i8 [[K:%.*]], [[TMP2]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[TMP3]], [[TMP2]]
; CHECK-NEXT: ret i1 [[RET]]
;
%t = shl i8 1, %c1
%t1 = and i8 %t, %k
%icmp = icmp eq i8 %t1, 0
%trunc = trunc i8 %k to i1
%not = xor i1 %trunc, true
%ret = select i1 %not, i1 true, i1 %icmp
ret i1 %ret
}

define <2 x i1> @trunc_or_icmp_vec(<2 x i8> %k, <2 x i8> %c1) {
; CHECK-LABEL: @trunc_or_icmp_vec(
; CHECK-NEXT: [[T:%.*]] = shl nuw <2 x i8> splat (i8 1), [[C1:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = or <2 x i8> [[T]], splat (i8 1)
; CHECK-NEXT: [[TMP2:%.*]] = and <2 x i8> [[K:%.*]], [[TMP1]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne <2 x i8> [[TMP2]], [[TMP1]]
; CHECK-NEXT: ret <2 x i1> [[RET]]
;
%t = shl <2 x i8> <i8 1, i8 1>, %c1
%t1 = and <2 x i8> %t, %k
%icmp = icmp eq <2 x i8> %t1, zeroinitializer
%trunc = trunc <2 x i8> %k to <2 x i1>
%not = xor <2 x i1> %trunc, <i1 true, i1 true>
%ret = or <2 x i1> %icmp, %not
ret <2 x i1> %ret
}

define i1 @neg_trunc_or_icmp_not_pow2(i8 %k, i8 %c1) {
; CHECK-LABEL: @neg_trunc_or_icmp_not_pow2(
; CHECK-NEXT: [[T1:%.*]] = and i8 [[C1:%.*]], [[K:%.*]]
; CHECK-NEXT: [[ICMP:%.*]] = icmp eq i8 [[T1]], 0
; CHECK-NEXT: [[TRUNC:%.*]] = trunc i8 [[K]] to i1
; CHECK-NEXT: [[NOT:%.*]] = xor i1 [[TRUNC]], true
; CHECK-NEXT: [[RET:%.*]] = or i1 [[ICMP]], [[NOT]]
; CHECK-NEXT: ret i1 [[RET]]
;
%t1 = and i8 %c1, %k
%icmp = icmp eq i8 %t1, 0
%trunc = trunc i8 %k to i1
%not = xor i1 %trunc, true
%ret = or i1 %icmp, %not
ret i1 %ret
}

define i1 @neg_trunc_or_icmp_not_trunc(i8 %k, i8 %c1) {
; CHECK-LABEL: @neg_trunc_or_icmp_not_trunc(
; CHECK-NEXT: [[T:%.*]] = shl nuw i8 1, [[C1:%.*]]
; CHECK-NEXT: [[T1:%.*]] = and i8 [[T]], [[K:%.*]]
; CHECK-NEXT: [[ICMP:%.*]] = icmp eq i8 [[T1]], 0
; CHECK-NEXT: [[TRUNC:%.*]] = trunc i8 [[K]] to i1
; CHECK-NEXT: [[RET:%.*]] = or i1 [[ICMP]], [[TRUNC]]
; CHECK-NEXT: ret i1 [[RET]]
;
%t = shl i8 1, %c1
%t1 = and i8 %t, %k
%icmp = icmp eq i8 %t1, 0
%trunc = trunc i8 %k to i1
%ret = or i1 %icmp, %trunc
ret i1 %ret
}

define i1 @neg_trunc_or_icmp_ne(i8 %k, i8 %c1) {
; CHECK-LABEL: @neg_trunc_or_icmp_ne(
; CHECK-NEXT: [[T:%.*]] = shl nuw i8 1, [[C1:%.*]]
; CHECK-NEXT: [[T1:%.*]] = and i8 [[T]], [[K:%.*]]
; CHECK-NEXT: [[ICMP:%.*]] = icmp ne i8 [[T1]], 0
; CHECK-NEXT: [[TRUNC:%.*]] = trunc i8 [[K]] to i1
; CHECK-NEXT: [[NOT:%.*]] = xor i1 [[TRUNC]], true
; CHECK-NEXT: [[RET:%.*]] = or i1 [[ICMP]], [[NOT]]
; CHECK-NEXT: ret i1 [[RET]]
;
%t = shl i8 1, %c1
%t1 = and i8 %t, %k
%icmp = icmp ne i8 %t1, 0
%trunc = trunc i8 %k to i1
%not = xor i1 %trunc, true
%ret = or i1 %icmp, %not
ret i1 %ret
}

define i1 @trunc_and_icmp_consts(i8 %k) {
; CHECK-LABEL: @trunc_and_icmp_consts(
; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[K:%.*]], 9
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[TMP1]], 9
; CHECK-NEXT: ret i1 [[RET]]
;
%trunc = trunc i8 %k to i1
%and = and i8 %k, 8
%icmp = icmp ne i8 %and, 0
%ret = and i1 %trunc, %icmp
ret i1 %ret
}

define i1 @icmp_and_trunc_consts(i8 %k) {
; CHECK-LABEL: @icmp_and_trunc_consts(
; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[K:%.*]], 9
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[TMP1]], 9
; CHECK-NEXT: ret i1 [[RET]]
;
%trunc = trunc i8 %k to i1
%and = and i8 %k, 8
%icmp = icmp ne i8 %and, 0
%ret = and i1 %icmp, %trunc
ret i1 %ret
}

define i1 @trunc_and_icmp(i8 %k, i8 %c1) {
; CHECK-LABEL: @trunc_and_icmp(
; CHECK-NEXT: [[T:%.*]] = shl nuw i8 1, [[C1:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = or i8 [[T]], 1
; CHECK-NEXT: [[TMP2:%.*]] = and i8 [[K:%.*]], [[TMP1]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[TMP2]], [[TMP1]]
; CHECK-NEXT: ret i1 [[RET]]
;
%t = shl i8 1, %c1
%t1 = and i8 %t, %k
%icmp = icmp ne i8 %t1, 0
%trunc = trunc i8 %k to i1
%ret = and i1 %icmp, %trunc
ret i1 %ret
}

define i1 @trunc_logical_and_icmp(i8 %k, i8 %c1) {
; CHECK-LABEL: @trunc_logical_and_icmp(
; CHECK-NEXT: [[T:%.*]] = shl nuw i8 1, [[C1:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = or i8 [[T]], 1
; CHECK-NEXT: [[TMP2:%.*]] = and i8 [[K:%.*]], [[TMP1]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[TMP2]], [[TMP1]]
; CHECK-NEXT: ret i1 [[RET]]
;
%t = shl i8 1, %c1
%t1 = and i8 %t, %k
%icmp = icmp ne i8 %t1, 0
%trunc = trunc i8 %k to i1
%ret = select i1 %icmp, i1 %trunc, i1 false
ret i1 %ret
}

define i1 @icmp_logical_and_trunc(i8 %k, i8 %c1) {
; CHECK-LABEL: @icmp_logical_and_trunc(
; CHECK-NEXT: [[T:%.*]] = shl nuw i8 1, [[C1:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = freeze i8 [[T]]
; CHECK-NEXT: [[TMP2:%.*]] = or i8 [[TMP1]], 1
; CHECK-NEXT: [[TMP3:%.*]] = and i8 [[K:%.*]], [[TMP2]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[TMP3]], [[TMP2]]
; CHECK-NEXT: ret i1 [[RET]]
;
%t = shl i8 1, %c1
%t1 = and i8 %t, %k
%icmp = icmp ne i8 %t1, 0
%trunc = trunc i8 %k to i1
%ret = select i1 %trunc, i1 %icmp, i1 false
ret i1 %ret
}

define i1 @trunc_logical_and_icmp_and_icmps(i8 %x, i8 %y, i8 %c1) {
; CHECK-LABEL: @trunc_logical_and_icmp_and_icmps(
; CHECK-NEXT: [[Z_SHIFT:%.*]] = shl nuw i8 1, [[Z:%.*]]
; CHECK-NEXT: [[C1:%.*]] = icmp eq i8 [[Y:%.*]], 42
; CHECK-NEXT: [[TMP1:%.*]] = or i8 [[Z_SHIFT]], 1
; CHECK-NEXT: [[TMP2:%.*]] = and i8 [[X:%.*]], [[TMP1]]
; CHECK-NEXT: [[TMP3:%.*]] = icmp eq i8 [[TMP2]], [[TMP1]]
; CHECK-NEXT: [[AND2:%.*]] = select i1 [[TMP3]], i1 [[C1]], i1 false
; CHECK-NEXT: ret i1 [[AND2]]
;
%t = shl i8 1, %c1
%t1 = and i8 %x, %t
%trunc = trunc i8 %x to i1
%icmp1 = icmp eq i8 %y, 42
%and1 = select i1 %trunc, i1 %icmp1, i1 false
%icmp2 = icmp ne i8 %t1, 0
%and2 = and i1 %icmp2, %and1
ret i1 %and2
}

define <2 x i1> @trunc_and_icmp_vec(<2 x i8> %k, <2 x i8> %c1) {
; CHECK-LABEL: @trunc_and_icmp_vec(
; CHECK-NEXT: [[T:%.*]] = shl nuw <2 x i8> splat (i8 1), [[C1:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = or <2 x i8> [[T]], splat (i8 1)
; CHECK-NEXT: [[TMP2:%.*]] = and <2 x i8> [[K:%.*]], [[TMP1]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq <2 x i8> [[TMP2]], [[TMP1]]
; CHECK-NEXT: ret <2 x i1> [[RET]]
;
%t = shl <2 x i8> <i8 1, i8 1>, %c1
%t1 = and <2 x i8> %t, %k
%icmp = icmp ne <2 x i8> %t1, zeroinitializer
%trunc = trunc <2 x i8> %k to <2 x i1>
%ret = and <2 x i1> %icmp, %trunc
ret <2 x i1> %ret
}

define i1 @trunc_and_icmp_not_pow2(i8 %k, i8 %c1) {
; CHECK-LABEL: @trunc_and_icmp_not_pow2(
; CHECK-NEXT: [[T1:%.*]] = and i8 [[C1:%.*]], [[K:%.*]]
; CHECK-NEXT: [[ICMP:%.*]] = icmp ne i8 [[T1]], 0
; CHECK-NEXT: [[TRUNC:%.*]] = trunc i8 [[K]] to i1
; CHECK-NEXT: [[RET:%.*]] = and i1 [[ICMP]], [[TRUNC]]
; CHECK-NEXT: ret i1 [[RET]]
;
%t1 = and i8 %c1, %k
%icmp = icmp ne i8 %t1, 0
%trunc = trunc i8 %k to i1
%ret = and i1 %icmp, %trunc
ret i1 %ret
}

define i1 @trunc_and_icmp_not_trunc(i8 %k, i8 %c1) {
; CHECK-LABEL: @trunc_and_icmp_not_trunc(
; CHECK-NEXT: [[T:%.*]] = shl nuw i8 1, [[C1:%.*]]
; CHECK-NEXT: [[T1:%.*]] = and i8 [[T]], [[K:%.*]]
; CHECK-NEXT: [[ICMP:%.*]] = icmp ne i8 [[T1]], 0
; CHECK-NEXT: [[TRUNC:%.*]] = trunc i8 [[K]] to i1
; CHECK-NEXT: [[NOT:%.*]] = xor i1 [[TRUNC]], true
; CHECK-NEXT: [[RET:%.*]] = and i1 [[ICMP]], [[NOT]]
; CHECK-NEXT: ret i1 [[RET]]
;
%t = shl i8 1, %c1
%t1 = and i8 %t, %k
%icmp = icmp ne i8 %t1, 0
%trunc = trunc i8 %k to i1
%not = xor i1 %trunc, true
%ret = and i1 %icmp, %not
ret i1 %ret
}

define i1 @trunc_and_icmp_eq(i8 %k, i8 %c1) {
; CHECK-LABEL: @trunc_and_icmp_eq(
; CHECK-NEXT: [[T:%.*]] = shl nuw i8 1, [[C1:%.*]]
; CHECK-NEXT: [[T1:%.*]] = and i8 [[T]], [[K:%.*]]
; CHECK-NEXT: [[ICMP:%.*]] = icmp eq i8 [[T1]], 0
; CHECK-NEXT: [[TRUNC:%.*]] = trunc i8 [[K]] to i1
; CHECK-NEXT: [[RET:%.*]] = and i1 [[ICMP]], [[TRUNC]]
; CHECK-NEXT: ret i1 [[RET]]
;
%t = shl i8 1, %c1
%t1 = and i8 %t, %k
%icmp = icmp eq i8 %t1, 0
%trunc = trunc i8 %k to i1
%ret = and i1 %icmp, %trunc
ret i1 %ret
}
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