// mul.with.overflow and adjust properly mask/size.
if (MulVal->hasNUsesOrMore(2)) {
Value *Mul = Builder.CreateExtractValue(Call, 0, "umul.value");
- for (User *U : MulVal->users()) {
+ for (auto UI = MulVal->user_begin(), UE = MulVal->user_end(); UI != UE;) {
+ User *U = *UI++;
if (U == &I || U == OtherVal)
continue;
if (TruncInst *TI = dyn_cast<TruncInst>(U)) {
ret void
}
+; Repro case for bug involving mutating a list while
+; iterating it.
+
+declare i16 @aux(i8)
+
+define i16 @iter_breaker(i16 %a, i16 %b) {
+; CHECK-LABEL: @iter_breaker(
+; CHECK-NEXT: [[UMUL:%.*]] = call { i16, i1 } @llvm.umul.with.overflow.i16(i16 [[A:%.*]], i16 [[B:%.*]])
+; CHECK-NEXT: [[UMUL_VALUE:%.*]] = extractvalue { i16, i1 } [[UMUL]], 0
+; CHECK-NEXT: [[DID_OVF:%.*]] = extractvalue { i16, i1 } [[UMUL]], 1
+; CHECK-NEXT: br i1 [[DID_OVF]], label [[RET1:%.*]], label [[RET2:%.*]]
+; CHECK: ret1:
+; CHECK-NEXT: [[TRUNC_REMAIN:%.*]] = trunc i16 [[UMUL_VALUE]] to i8
+; CHECK-NEXT: [[VAL:%.*]] = call i16 @aux(i8 [[TRUNC_REMAIN]])
+; CHECK-NEXT: ret i16 [[VAL]]
+; CHECK: ret2:
+; CHECK-NEXT: ret i16 [[UMUL_VALUE]]
+;
+ %a_wide = zext i16 %a to i32
+ %b_wide = zext i16 %b to i32
+ %mul_wide = mul i32 %a_wide, %b_wide ; uses of %mul_wide will be iterated
+
+ %trunc_remain = trunc i32 %mul_wide to i8 ; this use will be replaced w/ new value
+ ; when iteration visits it, switching
+ ; iteration to the uses of new value
+
+ %trunc_unnecessary = trunc i32 %mul_wide to i16 ; uses of %trunc_unnecessary will have
+ ; been updated to uses of new value
+ %did_ovf = icmp ugt i32 %mul_wide, 65535
+ br i1 %did_ovf, label %ret1, label %ret2
+
+ret1:
+ %val = call i16 @aux(i8 %trunc_remain)
+ ret i16 %val
+
+ret2:
+ ret i16 %trunc_unnecessary ; crash visiting this use after corrupting iterator
+}