BasicBlock *DeadBB = BlocksToErase[i];
for (Value::use_iterator UI = DeadBB->use_begin(), UE = DeadBB->use_end();
UI != UE; ) {
+ // Grab the user and then increment the iterator early, as the user
+ // will be deleted. Step past all adjacent uses from the same user.
+ Instruction *I = dyn_cast<Instruction>(*UI);
+ do { ++UI; } while (UI != UE && *UI == I);
+
// Ignore blockaddress users; BasicBlock's dtor will handle them.
- Instruction *I = dyn_cast<Instruction>(*UI++);
if (!I) continue;
bool Folded = ConstantFoldTerminator(I->getParent());
--- /dev/null
+; RUN: opt < %s -S -ipsccp | FileCheck %s
+; PR5596
+
+; IPSCCP should propagate the 0 argument, eliminate the switch, and propagate
+; the result.
+
+; CHECK: define i32 @main() noreturn nounwind {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: %call2 = tail call i32 @wwrite(i64 0) nounwind
+; CHECK-NEXT: ret i32 123
+
+define i32 @main() noreturn nounwind {
+entry:
+ %call2 = tail call i32 @wwrite(i64 0) nounwind
+ ret i32 %call2
+}
+
+define internal i32 @wwrite(i64 %i) nounwind readnone {
+entry:
+ switch i64 %i, label %sw.default [
+ i64 3, label %return
+ i64 10, label %return
+ ]
+
+sw.default:
+ ret i32 123
+
+return:
+ ret i32 0
+}