if (AllZeros)
return FoldGEPICmp(GEPLHS, GEPRHS->getOperand(0), Cond, I);
+ bool GEPsInBounds = GEPLHS->isInBounds() && GEPRHS->isInBounds();
if (GEPLHS->getNumOperands() == GEPRHS->getNumOperands()) {
// If the GEPs only differ by one index, compare it.
unsigned NumDifferences = 0; // Keep track of # differences.
ConstantInt::get(Type::getInt1Ty(I.getContext()),
ICmpInst::isTrueWhenEqual(Cond)));
- else if (NumDifferences == 1) {
+ else if (NumDifferences == 1 && GEPsInBounds) {
Value *LHSV = GEPLHS->getOperand(DiffOperand);
Value *RHSV = GEPRHS->getOperand(DiffOperand);
// Make sure we do a signed comparison here.
// Only lower this if the icmp is the only user of the GEP or if we expect
// the result to fold to a constant!
if (TD &&
+ GEPsInBounds &&
(isa<ConstantExpr>(GEPLHS) || GEPLHS->hasOneUse()) &&
(isa<ConstantExpr>(GEPRHS) || GEPRHS->hasOneUse())) {
// ((gep Ptr, OFFSET1) cmp (gep Ptr, OFFSET2) ---> (OFFSET1 cmp OFFSET2)
--- /dev/null
+; RUN: opt < %s -instcombine | lli
+; rdar://problem/9267970
+; ideally this test will run on a 32-bit host
+; must not discard GEPs that might overflow at runtime (aren't inbounds)
+
+define i32 @main(i32 %argc) {
+entry:
+ %tmp1 = add i32 %argc, -2
+ %tmp2 = add i32 %argc, 1879048192
+ %p = alloca i8
+ %p1 = getelementptr i8* %p, i32 %tmp1
+ %p2 = getelementptr i8* %p, i32 %tmp2
+ %cmp = icmp ult i8* %p1, %p2
+ br i1 %cmp, label %bbtrue, label %bbfalse
+bbtrue: ; preds = %entry
+ ret i32 -1
+bbfalse: ; preds = %entry
+ ret i32 0
+}