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[InstSimplify] Improve simplifyICmpWithConstant by using KnownBits info #76221

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[InstSimplify] Improve simplifyICmpWithConstant by using KnownBits info #76221

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8d80473
[InstSimplify] Add pre-commit tests. NFC.
dtcxzyw Dec 22, 2023
044cc4e
[InstSimplify] Improve `simplifyICmpWithConstant` by using KnownBits …
dtcxzyw Dec 22, 2023
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5 changes: 5 additions & 0 deletions llvm/include/llvm/Analysis/ValueTracking.h
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Expand Up @@ -863,6 +863,11 @@ ConstantRange computeConstantRange(const Value *V, bool ForSigned,
const DominatorTree *DT = nullptr,
unsigned Depth = 0);

/// Combine constant ranges from computeConstantRange() and computeKnownBits().
ConstantRange
computeConstantRangeIncludingKnownBits(const WithCache<const Value *> &V,
bool ForSigned, const SimplifyQuery &SQ);

/// Return true if this function can prove that the instruction I will
/// always transfer execution to one of its successors (including the next
/// instruction that follows within a basic block). E.g. this is not
Expand Down
10 changes: 5 additions & 5 deletions llvm/lib/Analysis/InstructionSimplify.cpp
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Expand Up @@ -3005,7 +3005,7 @@ static Value *simplifyICmpWithZero(CmpInst::Predicate Pred, Value *LHS,
}

static Value *simplifyICmpWithConstant(CmpInst::Predicate Pred, Value *LHS,
Value *RHS, const InstrInfoQuery &IIQ) {
Value *RHS, const SimplifyQuery &SQ) {
Type *ITy = getCompareTy(RHS); // The return type.

Value *X;
Expand All @@ -3031,8 +3031,8 @@ static Value *simplifyICmpWithConstant(CmpInst::Predicate Pred, Value *LHS,
if (RHS_CR.isFullSet())
return ConstantInt::getTrue(ITy);

ConstantRange LHS_CR =
computeConstantRange(LHS, CmpInst::isSigned(Pred), IIQ.UseInstrInfo);
ConstantRange LHS_CR = llvm::computeConstantRangeIncludingKnownBits(
LHS, CmpInst::isSigned(Pred), SQ);
if (!LHS_CR.isFullSet()) {
if (RHS_CR.contains(LHS_CR))
return ConstantInt::getTrue(ITy);
Expand All @@ -3043,7 +3043,7 @@ static Value *simplifyICmpWithConstant(CmpInst::Predicate Pred, Value *LHS,
// (mul nuw/nsw X, MulC) != C --> true (if C is not a multiple of MulC)
// (mul nuw/nsw X, MulC) == C --> false (if C is not a multiple of MulC)
const APInt *MulC;
if (IIQ.UseInstrInfo && ICmpInst::isEquality(Pred) &&
if (SQ.IIQ.UseInstrInfo && ICmpInst::isEquality(Pred) &&
((match(LHS, m_NUWMul(m_Value(), m_APIntAllowUndef(MulC))) &&
*MulC != 0 && C->urem(*MulC) != 0) ||
(match(LHS, m_NSWMul(m_Value(), m_APIntAllowUndef(MulC))) &&
Expand Down Expand Up @@ -3749,7 +3749,7 @@ static Value *simplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
if (Value *V = simplifyICmpWithZero(Pred, LHS, RHS, Q))
return V;

if (Value *V = simplifyICmpWithConstant(Pred, LHS, RHS, Q.IIQ))
if (Value *V = simplifyICmpWithConstant(Pred, LHS, RHS, Q))
return V;

// If both operands have range metadata, use the metadata
Expand Down
8 changes: 4 additions & 4 deletions llvm/lib/Analysis/ValueTracking.cpp
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Expand Up @@ -6289,10 +6289,10 @@ static OverflowResult mapOverflowResult(ConstantRange::OverflowResult OR) {
}

/// Combine constant ranges from computeConstantRange() and computeKnownBits().
static ConstantRange
computeConstantRangeIncludingKnownBits(const WithCache<const Value *> &V,
bool ForSigned,
const SimplifyQuery &SQ) {
ConstantRange
llvm::computeConstantRangeIncludingKnownBits(const WithCache<const Value *> &V,
bool ForSigned,
const SimplifyQuery &SQ) {
ConstantRange CR1 =
ConstantRange::fromKnownBits(V.getKnownBits(SQ), ForSigned);
ConstantRange CR2 = computeConstantRange(V, ForSigned, SQ.IIQ.UseInstrInfo);
Expand Down
12 changes: 2 additions & 10 deletions llvm/test/Analysis/ValueTracking/knownbits-bmi-pattern.ll
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Expand Up @@ -335,11 +335,7 @@ define i1 @blsi_ne_is_true(i32 %x) {

define <2 x i1> @blsi_ge_is_false_vec(<2 x i32> %x) {
; CHECK-LABEL: @blsi_ge_is_false_vec(
; CHECK-NEXT: [[X1:%.*]] = or <2 x i32> [[X:%.*]], <i32 10, i32 10>
; CHECK-NEXT: [[X2:%.*]] = sub nsw <2 x i32> zeroinitializer, [[X1]]
; CHECK-NEXT: [[X3:%.*]] = and <2 x i32> [[X2]], [[X]]
; CHECK-NEXT: [[Z:%.*]] = icmp ugt <2 x i32> [[X3]], <i32 7, i32 7>
; CHECK-NEXT: ret <2 x i1> [[Z]]
; CHECK-NEXT: ret <2 x i1> zeroinitializer
;
%x1 = or <2 x i32> %x, <i32 10, i32 10>
%x2 = sub <2 x i32> <i32 0, i32 0>, %x1
Expand All @@ -350,11 +346,7 @@ define <2 x i1> @blsi_ge_is_false_vec(<2 x i32> %x) {

define <2 x i1> @blsi_ge_is_false_diff_vec(<2 x i32> %x) {
; CHECK-LABEL: @blsi_ge_is_false_diff_vec(
; CHECK-NEXT: [[X1:%.*]] = or <2 x i32> [[X:%.*]], <i32 10, i32 11>
; CHECK-NEXT: [[X2:%.*]] = sub nsw <2 x i32> zeroinitializer, [[X1]]
; CHECK-NEXT: [[X3:%.*]] = and <2 x i32> [[X2]], [[X]]
; CHECK-NEXT: [[Z:%.*]] = icmp ugt <2 x i32> [[X3]], <i32 7, i32 7>
; CHECK-NEXT: ret <2 x i1> [[Z]]
; CHECK-NEXT: ret <2 x i1> zeroinitializer
;
%x1 = or <2 x i32> %x, <i32 10, i32 11>
%x2 = sub <2 x i32> <i32 0, i32 0>, %x1
Expand Down
9 changes: 3 additions & 6 deletions llvm/test/Analysis/ValueTracking/monotonic-phi.ll
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Expand Up @@ -484,8 +484,7 @@ define i1 @test_shl_zero_start(i8 %n) {
; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i8 [[A]], [[N:%.*]]
; CHECK-NEXT: br i1 [[CMP1]], label [[EXIT:%.*]], label [[LOOP]]
; CHECK: exit:
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i8 [[A]], 0
; CHECK-NEXT: ret i1 [[CMP]]
; CHECK-NEXT: ret i1 true
;
entry:
br label %loop
Expand Down Expand Up @@ -559,8 +558,7 @@ define i1 @test_lshr_zero_start(i8 %n) {
; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i8 [[A]], [[N:%.*]]
; CHECK-NEXT: br i1 [[CMP1]], label [[EXIT:%.*]], label [[LOOP]]
; CHECK: exit:
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i8 [[A]], 0
; CHECK-NEXT: ret i1 [[CMP]]
; CHECK-NEXT: ret i1 true
;
entry:
br label %loop
Expand Down Expand Up @@ -633,8 +631,7 @@ define i1 @test_ashr_zero_start(i8 %n) {
; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i8 [[A]], [[N:%.*]]
; CHECK-NEXT: br i1 [[CMP1]], label [[EXIT:%.*]], label [[LOOP]]
; CHECK: exit:
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i8 [[A]], 0
; CHECK-NEXT: ret i1 [[CMP]]
; CHECK-NEXT: ret i1 true
;
entry:
br label %loop
Expand Down
3 changes: 1 addition & 2 deletions llvm/test/Transforms/Attributor/lvi-after-jumpthreading.ll
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Expand Up @@ -148,8 +148,7 @@ define i32 @test4(i32 %i, i1 %f, i32 %n) {
; CHECK-NEXT: call void @dummy(i1 [[F]]) #[[ATTR2]]
; CHECK-NEXT: [[CONSUME:%.*]] = call i32 @exit()
; CHECK-NEXT: call void @llvm.assume(i1 noundef [[F]])
; CHECK-NEXT: [[COND:%.*]] = icmp eq i1 [[F]], false
; CHECK-NEXT: br i1 [[COND]], label [[EXIT]], label [[CONT:%.*]]
; CHECK-NEXT: br label [[CONT:%.*]]
; CHECK: exit2:
; CHECK-NEXT: ret i32 30
;
Expand Down
8 changes: 2 additions & 6 deletions llvm/test/Transforms/InstSimplify/call.ll
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Expand Up @@ -1582,9 +1582,7 @@ define i1 @ctlz_i1_non_poison_eq_false(i1 %x) {

define i1 @ctlz_i1_poison_eq_false(i1 %x) {
; CHECK-LABEL: @ctlz_i1_poison_eq_false(
; CHECK-NEXT: [[CT:%.*]] = call i1 @llvm.ctlz.i1(i1 [[X:%.*]], i1 true)
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i1 [[CT]], false
; CHECK-NEXT: ret i1 [[CMP]]
; CHECK-NEXT: ret i1 true
;
%ct = call i1 @llvm.ctlz.i1(i1 %x, i1 true)
%cmp = icmp eq i1 %ct, false
Expand All @@ -1604,9 +1602,7 @@ define i1 @cttz_i1_non_poison_eq_false(i1 %x) {

define i1 @cttz_i1_poison_eq_false(i1 %x) {
; CHECK-LABEL: @cttz_i1_poison_eq_false(
; CHECK-NEXT: [[CT:%.*]] = call i1 @llvm.cttz.i1(i1 [[X:%.*]], i1 true)
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i1 [[CT]], false
; CHECK-NEXT: ret i1 [[CMP]]
; CHECK-NEXT: ret i1 true
;
%ct = call i1 @llvm.cttz.i1(i1 %x, i1 true)
%cmp = icmp eq i1 %ct, false
Expand Down
28 changes: 19 additions & 9 deletions llvm/test/Transforms/InstSimplify/icmp-constant.ll
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Expand Up @@ -433,9 +433,7 @@ define <2 x i1> @or1_vec_partial_undef(<2 x i32> %X) {
; Single bit OR.
define i1 @or2_true(i8 %x) {
; CHECK-LABEL: @or2_true(
; CHECK-NEXT: [[Y:%.*]] = or i8 [[X:%.*]], 64
; CHECK-NEXT: [[Z:%.*]] = icmp sge i8 [[Y]], -64
; CHECK-NEXT: ret i1 [[Z]]
; CHECK-NEXT: ret i1 true
;
%y = or i8 %x, 64
%z = icmp sge i8 %y, -64
Expand All @@ -457,9 +455,7 @@ define i1 @or2_unknown(i8 %x) {
; 78 = 0b01001110; -50 = 0b11001110
define i1 @or3_true(i8 %x) {
; CHECK-LABEL: @or3_true(
; CHECK-NEXT: [[Y:%.*]] = or i8 [[X:%.*]], 78
; CHECK-NEXT: [[Z:%.*]] = icmp sge i8 [[Y]], -50
; CHECK-NEXT: ret i1 [[Z]]
; CHECK-NEXT: ret i1 true
;
%y = or i8 %x, 78
%z = icmp sge i8 %y, -50
Expand Down Expand Up @@ -573,9 +569,7 @@ define i1 @and3_unknown1(i8 %x) {

define i1 @and3_true2(i8 %x) {
; CHECK-LABEL: @and3_true2(
; CHECK-NEXT: [[Y:%.*]] = and i8 [[X:%.*]], -75
; CHECK-NEXT: [[Z:%.*]] = icmp sle i8 [[Y]], 53
; CHECK-NEXT: ret i1 [[Z]]
; CHECK-NEXT: ret i1 true
;
%y = and i8 %x, -75
%z = icmp sle i8 %y, 53
Expand Down Expand Up @@ -1140,3 +1134,19 @@ define <2 x i1> @heterogeneous_constvector(<2 x i8> %x) {
%c = icmp ult <2 x i8> %x, <i8 undef, i8 poison>
ret <2 x i1> %c
}

define i8 @infer_sub_with_knownbits_info(i8 %a, i8 %b) {
; CHECK-LABEL: @infer_sub_with_knownbits_info(
; CHECK-NEXT: [[A1:%.*]] = or i8 [[A:%.*]], 1
; CHECK-NEXT: [[A2:%.*]] = shl i8 [[B:%.*]], 1
; CHECK-NEXT: [[SUB:%.*]] = sub i8 [[A1]], [[A2]]
; CHECK-NEXT: ret i8 [[SUB]]
;
%a1 = or i8 %a, 1
%a2 = shl i8 %b, 1
%sub = sub i8 %a1, %a2
%umax = tail call i8 @llvm.umax.i8(i8 %sub, i8 1)
ret i8 %umax
}

declare i8 @llvm.umax.i8(i8, i8)
9 changes: 8 additions & 1 deletion llvm/test/Transforms/JumpThreading/pr62908.ll
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Expand Up @@ -5,7 +5,14 @@

define i32 @test() {
; CHECK-LABEL: define i32 @test() {
; CHECK-NEXT: end:
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[END:%.*]]
; CHECK: unreachable:
; CHECK-NEXT: [[SH_PROM:%.*]] = zext i32 -1 to i64
; CHECK-NEXT: [[SHL:%.*]] = shl nsw i64 -1, [[SH_PROM]]
; CHECK-NEXT: [[CONV:%.*]] = trunc i64 [[SHL]] to i32
; CHECK-NEXT: br label [[END]]
; CHECK: end:
; CHECK-NEXT: ret i32 0
;
entry:
Expand Down
8 changes: 2 additions & 6 deletions llvm/test/Transforms/LoopUnroll/runtime-loop-multiple-exits.ll
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Expand Up @@ -4578,10 +4578,8 @@ define void @test8() {
; EPILOG-BLOCK: outerloop:
; EPILOG-BLOCK-NEXT: %i = phi i64 [ 3, %bb ], [ 0, %outerloop.loopexit.1 ]
; EPILOG-BLOCK-NEXT: %0 = sub i64 100, %i
; EPILOG-BLOCK-NEXT: %1 = sub i64 99, %i
; EPILOG-BLOCK-NEXT: %xtraiter = and i64 %0, 1
; EPILOG-BLOCK-NEXT: %2 = icmp ult i64 %1, 1
; EPILOG-BLOCK-NEXT: br i1 %2, label %exit.unr-lcssa, label %outerloop.new
; EPILOG-BLOCK-NEXT: br i1 false, label %exit.unr-lcssa, label %outerloop.new
; EPILOG-BLOCK: outerloop.new:
; EPILOG-BLOCK-NEXT: %unroll_iter = sub i64 %0, %xtraiter
; EPILOG-BLOCK-NEXT: br label %innerH
Expand Down Expand Up @@ -4711,7 +4709,6 @@ define void @test8() {
; PROLOG-BLOCK: outerloop:
; PROLOG-BLOCK-NEXT: %i = phi i64 [ 3, %bb ], [ 0, %outerloop.loopexit.1 ]
; PROLOG-BLOCK-NEXT: %0 = sub i64 100, %i
; PROLOG-BLOCK-NEXT: %1 = sub i64 99, %i
; PROLOG-BLOCK-NEXT: %xtraiter = and i64 %0, 1
; PROLOG-BLOCK-NEXT: %lcmp.mod = icmp ne i64 %xtraiter, 0
; PROLOG-BLOCK-NEXT: br i1 %lcmp.mod, label %innerH.prol.preheader, label %innerH.prol.loopexit
Expand All @@ -4724,8 +4721,7 @@ define void @test8() {
; PROLOG-BLOCK-NEXT: br label %innerH.prol.loopexit
; PROLOG-BLOCK: innerH.prol.loopexit:
; PROLOG-BLOCK-NEXT: %i3.unr = phi i64 [ %i, %outerloop ], [ %i4.prol, %latch.prol ]
; PROLOG-BLOCK-NEXT: %2 = icmp ult i64 %1, 1
; PROLOG-BLOCK-NEXT: br i1 %2, label %exit.loopexit, label %outerloop.new
; PROLOG-BLOCK-NEXT: br i1 false, label %exit.loopexit, label %outerloop.new
; PROLOG-BLOCK: outerloop.new:
; PROLOG-BLOCK-NEXT: br label %innerH
; PROLOG-BLOCK: innerH:
Expand Down
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