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[InstSimplify] Simplify 'x u>= 1' to true when x is known non-zero (#145204)

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Iris Shi 2025-06-22 13:32:19 +08:00 committed by GitHub
parent fa0b84f23c
commit f51d8730b3
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2 changed files with 127 additions and 4 deletions
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11
llvm/lib/Analysis/InstructionSimplify.cpp
View File

@ -2981,7 +2981,7 @@ static Value *simplifyICmpWithZero(CmpPredicate Pred, Value *LHS, Value *RHS,
}
static Value *simplifyICmpWithConstant(CmpPredicate Pred, Value *LHS,
Value *RHS, const InstrInfoQuery &IIQ) {
Value *RHS, const SimplifyQuery &Q) {
Type *ITy = getCompareTy(RHS); // The return type.
Value *X;
@ -3007,7 +3007,7 @@ static Value *simplifyICmpWithConstant(CmpPredicate Pred, Value *LHS,
return ConstantInt::getTrue(ITy);
ConstantRange LHS_CR =
computeConstantRange(LHS, CmpInst::isSigned(Pred), IIQ.UseInstrInfo);
computeConstantRange(LHS, CmpInst::isSigned(Pred), Q.IIQ.UseInstrInfo);
if (!LHS_CR.isFullSet()) {
if (RHS_CR.contains(LHS_CR))
return ConstantInt::getTrue(ITy);
@ -3018,13 +3018,16 @@ static Value *simplifyICmpWithConstant(CmpPredicate 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 (Q.IIQ.UseInstrInfo && ICmpInst::isEquality(Pred) &&
((match(LHS, m_NUWMul(m_Value(), m_APIntAllowPoison(MulC))) &&
*MulC != 0 && C->urem(*MulC) != 0) ||
(match(LHS, m_NSWMul(m_Value(), m_APIntAllowPoison(MulC))) &&
*MulC != 0 && C->srem(*MulC) != 0)))
return ConstantInt::get(ITy, Pred == ICmpInst::ICMP_NE);
if (Pred == ICmpInst::ICMP_UGE && C->isOne() && isKnownNonZero(LHS, Q))
return ConstantInt::getTrue(ITy);
return nullptr;
}
@ -3776,7 +3779,7 @@ static Value *simplifyICmpInst(CmpPredicate Pred, 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

120
llvm/test/Transforms/InstSimplify/umax-1.ll Normal file
View File

@ -0,0 +1,120 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt < %s -passes=instsimplify -S | FileCheck %s
define i32 @known_non_zero_by_or(i32 %x, i32 %y) {
; CHECK-LABEL: define i32 @known_non_zero_by_or(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[COND:%.*]] = icmp ne i32 [[X]], 0
; CHECK-NEXT: br i1 [[COND]], label %[[IF_THEN:.*]], label %[[IF_ELSE:.*]]
; CHECK: [[IF_THEN]]:
; CHECK-NEXT: [[VAL:%.*]] = or i32 [[X]], [[Y]]
; CHECK-NEXT: ret i32 [[VAL]]
; CHECK: [[IF_ELSE]]:
; CHECK-NEXT: ret i32 0
;
%cond = icmp ne i32 %x, 0
br i1 %cond, label %if.then, label %if.else
if.then:
%val = or i32 %x, %y
%max = call i32 @llvm.umax.i32(i32 %val, i32 1)
ret i32 %max
if.else:
ret i32 0
}
define i32 @known_non_zero_by_mul(i32 %x) {
; CHECK-LABEL: define i32 @known_non_zero_by_mul(
; CHECK-SAME: i32 [[X:%.*]]) {
; CHECK-NEXT: [[COND:%.*]] = icmp ne i32 [[X]], 0
; CHECK-NEXT: br i1 [[COND]], label %[[IF_THEN:.*]], label %[[IF_ELSE:.*]]
; CHECK: [[IF_THEN]]:
; CHECK-NEXT: [[NONZERO1:%.*]] = mul nuw i32 [[X]], 3
; CHECK-NEXT: ret i32 [[NONZERO1]]
; CHECK: [[IF_ELSE]]:
; CHECK-NEXT: ret i32 0
;
%cond = icmp ne i32 %x, 0
br i1 %cond, label %if.then, label %if.else
if.then:
%nonzero = mul nuw i32 %x, 3
%max = call i32 @llvm.umax.i32(i32 %nonzero, i32 1)
ret i32 %max
if.else:
ret i32 0
}
define i32 @known_non_zero_commute(i32 %x, i32 %y) {
; CHECK-LABEL: define i32 @known_non_zero_commute(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[COND:%.*]] = icmp ne i32 [[X]], 0
; CHECK-NEXT: br i1 [[COND]], label %[[IF_THEN:.*]], label %[[IF_ELSE:.*]]
; CHECK: [[IF_THEN]]:
; CHECK-NEXT: [[VAL:%.*]] = or i32 [[X]], [[Y]]
; CHECK-NEXT: ret i32 [[VAL]]
; CHECK: [[IF_ELSE]]:
; CHECK-NEXT: ret i32 0
;
%cond = icmp ne i32 %x, 0
br i1 %cond, label %if.then, label %if.else
if.then:
%val = or i32 %x, %y
%max = call i32 @llvm.umax.i32(i32 1, i32 %val)
ret i32 %max
if.else:
ret i32 0
}
; Negative
define i32 @umax_ge_2(i32 %x, i32 %y) {
; CHECK-LABEL: define i32 @umax_ge_2(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[COND:%.*]] = icmp ne i32 [[X]], 0
; CHECK-NEXT: br i1 [[COND]], label %[[IF_THEN:.*]], label %[[IF_ELSE:.*]]
; CHECK: [[IF_THEN]]:
; CHECK-NEXT: [[VAL:%.*]] = or i32 [[X]], [[Y]]
; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.umax.i32(i32 [[VAL]], i32 2)
; CHECK-NEXT: ret i32 [[MAX]]
; CHECK: [[IF_ELSE]]:
; CHECK-NEXT: ret i32 0
;
%cond = icmp ne i32 %x, 0
br i1 %cond, label %if.then, label %if.else
if.then:
%val = or i32 %x, %y
%max = call i32 @llvm.umax.i32(i32 %val, i32 2)
ret i32 %max
if.else:
ret i32 0
}
define i32 @unknown_by_and(i32 %x, i32 %y) {
; CHECK-LABEL: define i32 @unknown_by_and(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[COND:%.*]] = icmp ne i32 [[X]], 0
; CHECK-NEXT: br i1 [[COND]], label %[[IF_THEN:.*]], label %[[IF_ELSE:.*]]
; CHECK: [[IF_THEN]]:
; CHECK-NEXT: [[VAL:%.*]] = and i32 [[X]], [[Y]]
; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.umax.i32(i32 [[VAL]], i32 1)
; CHECK-NEXT: ret i32 [[MAX]]
; CHECK: [[IF_ELSE]]:
; CHECK-NEXT: ret i32 0
;
%cond = icmp ne i32 %x, 0
br i1 %cond, label %if.then, label %if.else
if.then:
%val = and i32 %x, %y
%max = call i32 @llvm.umax.i32(i32 %val, i32 1)
ret i32 %max
if.else:
ret i32 0
}