Fix a use of an invalidated iterator in the case where there are multiple

adjacent uses of a dead basic block from the same user. This fixes PR5596.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89658 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/IPConstantProp/user-with-multiple-uses.ll

@@ -0,0 +1,30 @@
+; 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
+}