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[InstCombine] Implement folds of icmp of UCMP/SCMP call and a constant #96118

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Jun 22, 2024
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[InstCombine] Implement folds of icmp of UCMP/SCMP call and a constant #96118

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af26a20
[InstCombine] Added tests for various folds of icmp (UCMP/SCMP, C)
Poseydon42 Jun 19, 2024
9d00eb3
[InstCombine] Implement folds of icmp with UCMP/SCMP and a constant
Poseydon42 Jun 19, 2024
b2ffd9c
Remove redundant cases and fix formatting
Poseydon42 Jun 20, 2024
451ceb6
Prettify the code
Poseydon42 Jun 21, 2024
c7389c2
Add elseif's istead of a list of mutually exclusive ifs
Poseydon42 Jun 21, 2024
af5c172
Replace .value() with dereference operator
Poseydon42 Jun 21, 2024
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51 changes: 51 additions & 0 deletions llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3926,6 +3926,52 @@ foldICmpUSubSatOrUAddSatWithConstant(ICmpInst::Predicate Pred,
ConstantInt::get(Op1->getType(), EquivInt));
}

static Instruction *
foldICmpOfCmpIntrinsicWithConstant(ICmpInst::Predicate Pred, IntrinsicInst *I,
const APInt &C,
InstCombiner::BuilderTy &Builder) {
std::optional<ICmpInst::Predicate> NewPredicate = std::nullopt;
switch (Pred) {
case ICmpInst::ICMP_EQ:
case ICmpInst::ICMP_NE:
if (C.isZero())
NewPredicate = Pred;
else if (C.isOne())
NewPredicate =
Pred == ICmpInst::ICMP_EQ ? ICmpInst::ICMP_UGT : ICmpInst::ICMP_ULE;
else if (C.isAllOnes())
NewPredicate =
Pred == ICmpInst::ICMP_EQ ? ICmpInst::ICMP_ULT : ICmpInst::ICMP_UGE;
break;

case ICmpInst::ICMP_SGT:
if (C.isAllOnes())
NewPredicate = ICmpInst::ICMP_UGE;
else if (C.isZero())
NewPredicate = ICmpInst::ICMP_UGT;
break;

case ICmpInst::ICMP_SLT:
if (C.isZero())
NewPredicate = ICmpInst::ICMP_ULT;
else if (C.isOne())
NewPredicate = ICmpInst::ICMP_ULE;
break;

default:
break;
}

if (!NewPredicate)
return nullptr;

if (I->getIntrinsicID() == Intrinsic::scmp)
NewPredicate = ICmpInst::getSignedPredicate(*NewPredicate);
Value *LHS = I->getOperand(0);
Value *RHS = I->getOperand(1);
return new ICmpInst(*NewPredicate, LHS, RHS);
}

/// Fold an icmp with LLVM intrinsic and constant operand: icmp Pred II, C.
Instruction *InstCombinerImpl::foldICmpIntrinsicWithConstant(ICmpInst &Cmp,
IntrinsicInst *II,
Expand All @@ -3947,6 +3993,11 @@ Instruction *InstCombinerImpl::foldICmpIntrinsicWithConstant(ICmpInst &Cmp,
if (Instruction *R = foldCtpopPow2Test(Cmp, II, C, Builder, Q))
return R;
} break;
case Intrinsic::scmp:
case Intrinsic::ucmp:
if (auto *Folded = foldICmpOfCmpIntrinsicWithConstant(Pred, II, C, Builder))
return Folded;
break;
}

if (Cmp.isEquality())
Expand Down
156 changes: 156 additions & 0 deletions llvm/test/Transforms/InstCombine/scmp.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,156 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt < %s -passes=instcombine -S | FileCheck %s

define i1 @scmp_eq_0(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @scmp_eq_0(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.scmp(i32 %x, i32 %y)
%2 = icmp eq i8 %1, 0
ret i1 %2
}

define i1 @scmp_ne_0(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @scmp_ne_0(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.scmp(i32 %x, i32 %y)
%2 = icmp ne i8 %1, 0
ret i1 %2
}

define i1 @scmp_eq_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @scmp_eq_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.scmp(i32 %x, i32 %y)
%2 = icmp eq i8 %1, 1
ret i1 %2
}

define i1 @scmp_ne_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @scmp_ne_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp sle i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.scmp(i32 %x, i32 %y)
%2 = icmp ne i8 %1, 1
ret i1 %2
}

define i1 @scmp_eq_negative_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @scmp_eq_negative_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp slt i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.scmp(i32 %x, i32 %y)
%2 = icmp eq i8 %1, -1
ret i1 %2
}

define i1 @scmp_ne_negative_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @scmp_ne_negative_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp sge i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.scmp(i32 %x, i32 %y)
%2 = icmp ne i8 %1, -1
ret i1 %2
}

define i1 @scmp_sgt_0(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @scmp_sgt_0(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.scmp(i32 %x, i32 %y)
%2 = icmp sgt i8 %1, 0
ret i1 %2
}

define i1 @scmp_sgt_neg_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @scmp_sgt_neg_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp sge i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.scmp(i32 %x, i32 %y)
%2 = icmp sgt i8 %1, -1
ret i1 %2
}

define i1 @scmp_sge_0(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @scmp_sge_0(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp sge i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.scmp(i32 %x, i32 %y)
%2 = icmp sge i8 %1, 0
ret i1 %2
}

define i1 @scmp_sge_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @scmp_sge_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.scmp(i32 %x, i32 %y)
%2 = icmp sge i8 %1, 1
ret i1 %2
}

define i1 @scmp_slt_0(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @scmp_slt_0(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp slt i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.scmp(i32 %x, i32 %y)
%2 = icmp slt i8 %1, 0
ret i1 %2
}

define i1 @scmp_slt_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @scmp_slt_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp sle i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.scmp(i32 %x, i32 %y)
%2 = icmp slt i8 %1, 1
ret i1 %2
}

define i1 @scmp_sle_0(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @scmp_sle_0(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp sle i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.scmp(i32 %x, i32 %y)
%2 = icmp sle i8 %1, 0
ret i1 %2
}

define i1 @scmp_sle_neg_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @scmp_sle_neg_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp slt i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.scmp(i32 %x, i32 %y)
%2 = icmp sle i8 %1, -1
ret i1 %2
}
156 changes: 156 additions & 0 deletions llvm/test/Transforms/InstCombine/ucmp.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,156 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt < %s -passes=instcombine -S | FileCheck %s

define i1 @ucmp_eq_0(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @ucmp_eq_0(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
%2 = icmp eq i8 %1, 0
ret i1 %2
}

define i1 @ucmp_ne_0(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @ucmp_ne_0(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
%2 = icmp ne i8 %1, 0
ret i1 %2
}

define i1 @ucmp_eq_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @ucmp_eq_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp ugt i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
%2 = icmp eq i8 %1, 1
ret i1 %2
}

define i1 @ucmp_ne_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @ucmp_ne_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp ule i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
%2 = icmp ne i8 %1, 1
ret i1 %2
}

define i1 @ucmp_eq_negative_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @ucmp_eq_negative_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
%2 = icmp eq i8 %1, -1
ret i1 %2
}

define i1 @ucmp_ne_negative_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @ucmp_ne_negative_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp uge i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
%2 = icmp ne i8 %1, -1
ret i1 %2
}

define i1 @ucmp_sgt_0(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @ucmp_sgt_0(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp ugt i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
%2 = icmp sgt i8 %1, 0
ret i1 %2
}

define i1 @ucmp_sgt_neg_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @ucmp_sgt_neg_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp uge i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
%2 = icmp sgt i8 %1, -1
ret i1 %2
}

define i1 @ucmp_sge_0(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @ucmp_sge_0(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp uge i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
%2 = icmp sge i8 %1, 0
ret i1 %2
}

define i1 @ucmp_sge_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @ucmp_sge_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp ugt i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
%2 = icmp sge i8 %1, 1
ret i1 %2
}

define i1 @ucmp_slt_0(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @ucmp_slt_0(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
%2 = icmp slt i8 %1, 0
ret i1 %2
}

define i1 @ucmp_slt_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @ucmp_slt_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp ule i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
%2 = icmp slt i8 %1, 1
ret i1 %2
}

define i1 @ucmp_sle_0(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @ucmp_sle_0(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp ule i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
%2 = icmp sle i8 %1, 0
ret i1 %2
}

define i1 @ucmp_sle_neg_1(i32 %x, i32 %y) {
; CHECK-LABEL: define i1 @ucmp_sle_neg_1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i32 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[TMP2]]
;
%1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
%2 = icmp sle i8 %1, -1
ret i1 %2
}
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