Fixed instruction corruption bug for multiple returns.

tests_lit/asan_tests/multiple_returns.ll

+; Check that functions with multiple returns are correctly instrumented
+
+; REQUIRES: allow_dump
+
+; RUN: %p2i -i %s --args -verbose=inst -threads=0 -fsanitize-address \
+; RUN:     | FileCheck --check-prefix=DUMP %s
+
+define internal void @ret_twice(i32 %condarg) {
+  %local1 = alloca i8, i32 4, align 4
+  %local2 = alloca i8, i32 4, align 4
+  %cond = icmp ne i32 %condarg, 0
+  br i1 %cond, label %yes, label %no
+yes:
+  ret void
+no:
+  ret void
+}
+
+; DUMP-LABEL: ================ Instrumented CFG ================
+; DUMP-NEXT: define internal void @ret_twice(i32 %condarg) {
+; DUMP-NEXT: __0:
+; DUMP-NEXT:   %local1 = alloca i8, i32 64, align 8
+; DUMP-NEXT:   %local2 = alloca i8, i32 64, align 8
+; DUMP-NEXT:   %__$rz2 = alloca i8, i32 32, align 8
+; DUMP-NEXT:   call void @__asan_poison(i32 %__$rz2, i32 32)
+; DUMP-NEXT:   %__$rz0 = add i32 %local1, 4
+; DUMP-NEXT:   call void @__asan_poison(i32 %__$rz0, i32 60)
+; DUMP-NEXT:   %__$rz1 = add i32 %local2, 4
+; DUMP-NEXT:   call void @__asan_poison(i32 %__$rz1, i32 60)
+; DUMP-NEXT:   %cond = icmp ne i32 %condarg, 0
+; DUMP-NEXT:   br i1 %cond, label %yes, label %no
+; DUMP-NEXT: yes:
+; DUMP-NEXT:   call void @__asan_unpoison(i32 %__$rz0, i32 60)
+; DUMP-NEXT:   call void @__asan_unpoison(i32 %__$rz1, i32 60)
+; DUMP-NEXT:   call void @__asan_unpoison(i32 %__$rz2, i32 32)
+; DUMP-NEXT:   ret void
+; DUMP-NEXT: no:
+; DUMP-NEXT:   call void @__asan_unpoison(i32 %__$rz0, i32 60)
+; DUMP-NEXT:   call void @__asan_unpoison(i32 %__$rz1, i32 60)
+; DUMP-NEXT:   call void @__asan_unpoison(i32 %__$rz2, i32 32)
+; DUMP-NEXT:   ret void
+; DUMP-NEXT: }