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An argument and a local identified object (eg. a noalias call) could turn out

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equal if both are null. In the test, scope type %t and global @y by adding a
'gep' prefix to them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151452 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2012-02-25 20:19:07 +00:00
parent 6bfb9d6a13
commit 28e215ba63
2 changed files with 37 additions and 26 deletions
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25
lib/Analysis/InstructionSimplify.cpp
View File

@ -1626,21 +1626,22 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
LHSPtr = stripPointerAdjustments(LHSPtr);
if (llvm::isIdentifiedObject(LHSPtr)) {
RHSPtr = stripPointerAdjustments(RHSPtr);
// If both sides are different identified objects, they aren't equal unless
// they're null.
if (LHSPtr != RHSPtr && llvm::isIdentifiedObject(RHSPtr) &&
(llvm::isKnownNonNull(LHSPtr) || llvm::isKnownNonNull(RHSPtr)))
return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
if (llvm::isKnownNonNull(LHSPtr) || llvm::isKnownNonNull(RHSPtr)) {
// If both sides are different identified objects, they aren't equal
// unless they're null.
if (LHSPtr != RHSPtr && llvm::isIdentifiedObject(RHSPtr))
return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
// Assume that the null is on the right.
// A local identified object (alloca or noalias call) can't equal any
// incoming argument, unless they're both null.
if ((isa<Instruction>(LHSPtr) && isa<Argument>(RHSPtr)) ||
(isa<Instruction>(RHSPtr) && isa<Argument>(LHSPtr)))
return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
}
// Assume that the constant null is on the right.
if (llvm::isKnownNonNull(LHSPtr) && isa<ConstantPointerNull>(RHSPtr))
return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
// A local instruction (alloca or noalias call) can't equal any incoming
// argument.
if ((isa<Instruction>(LHSPtr) && isa<Argument>(RHSPtr)) ||
(isa<Instruction>(RHSPtr) && isa<Argument>(LHSPtr)))
return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
}
// If we are comparing with zero then try hard since this is a common case.

38
test/Transforms/InstSimplify/compare.ll
View File

@ -41,14 +41,15 @@ define i1 @gep2() {
}
; PR11238
%t = type { i32, i32 }
@y = global %t zeroinitializer, align 8
%gept = type { i32, i32 }
@gepy = global %gept zeroinitializer, align 8
@gepz = extern_weak global %gept
define i1 @gep3() {
; CHECK: @gep3
%x = alloca %t, align 8
%a = getelementptr %t* %x, i64 0, i32 0
%b = getelementptr %t* %x, i64 0, i32 1
%x = alloca %gept, align 8
%a = getelementptr %gept* %x, i64 0, i32 0
%b = getelementptr %gept* %x, i64 0, i32 1
%equal = icmp eq i32* %a, %b
ret i1 %equal
; CHECK-NEXT: ret i1 false
@ -56,9 +57,9 @@ define i1 @gep3() {
define i1 @gep4() {
; CHECK: @gep4
%x = alloca %t, align 8
%a = getelementptr %t* @y, i64 0, i32 0
%b = getelementptr %t* @y, i64 0, i32 1
%x = alloca %gept, align 8
%a = getelementptr %gept* @gepy, i64 0, i32 0
%b = getelementptr %gept* @gepy, i64 0, i32 1
%equal = icmp eq i32* %a, %b
ret i1 %equal
; CHECK-NEXT: ret i1 false
@ -66,24 +67,33 @@ define i1 @gep4() {
define i1 @gep5() {
; CHECK: @gep5
%x = alloca %t, align 8
%a = getelementptr inbounds %t* %x, i64 0, i32 1
%b = getelementptr %t* @y, i64 0, i32 0
%x = alloca %gept, align 8
%a = getelementptr inbounds %gept* %x, i64 0, i32 1
%b = getelementptr %gept* @gepy, i64 0, i32 0
%equal = icmp eq i32* %a, %b
ret i1 %equal
; CHECK-NEXT: ret i1 false
}
define i1 @gep6(%t* %x) {
define i1 @gep6(%gept* %x) {
; Same as @gep3 but potentially null.
; CHECK: @gep6
%a = getelementptr %t* %x, i64 0, i32 0
%b = getelementptr %t* %x, i64 0, i32 1
%a = getelementptr %gept* %x, i64 0, i32 0
%b = getelementptr %gept* %x, i64 0, i32 1
%equal = icmp eq i32* %a, %b
ret i1 %equal
; CHECK-NEXT: ret i1 false
}
define i1 @gep7(%gept* %x) {
; CHECK: @gep7
%a = getelementptr %gept* %x, i64 0, i32 0
%b = getelementptr %gept* @gepz, i64 0, i32 0
%equal = icmp eq i32* %a, %b
ret i1 %equal
; CHECK: ret i1 %equal
}
define i1 @zext(i32 %x) {
; CHECK: @zext
%e1 = zext i32 %x to i64