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[C/C++ PATCH] Fix bogus warning with -Wswitch-unreachable (PR c/71249)
- From: Marek Polacek <polacek at redhat dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Cc: Jason Merrill <jason at redhat dot com>, Joseph Myers <joseph at codesourcery dot com>
- Date: Tue, 24 May 2016 13:41:15 +0200
- Subject: [C/C++ PATCH] Fix bogus warning with -Wswitch-unreachable (PR c/71249)
- Authentication-results: sourceware.org; auth=none
Martin S. noticed that cc1plus bogusly warns on the following test. That's
because I didn't realize that GIMPLE_BINDs might be nested in C++ so we need to
look through them, and only then get the first statement in the seq.
Bootstrapped/regtested on x86_64-linux, ok for trunk?
2016-05-24 Marek Polacek <polacek@redhat.com>
PR c/71249
* gimplify.c (gimplify_switch_expr): Look into the innermost lexical
scope.
* c-c++-common/Wswitch-unreachable-2.c: New test.
diff --git gcc/gimplify.c gcc/gimplify.c
index 6473544..5c5e9d6 100644
--- gcc/gimplify.c
+++ gcc/gimplify.c
@@ -1605,8 +1605,9 @@ gimplify_switch_expr (tree *expr_p, gimple_seq *pre_p)
&& switch_body_seq != NULL)
{
gimple_seq seq = switch_body_seq;
- if (gimple_code (switch_body_seq) == GIMPLE_BIND)
- seq = gimple_bind_body (as_a <gbind *> (switch_body_seq));
+ /* Look into the innermost lexical scope. */
+ while (gimple_code (seq) == GIMPLE_BIND)
+ seq = gimple_bind_body (as_a <gbind *> (seq));
gimple *stmt = gimple_seq_first_stmt (seq);
enum gimple_code code = gimple_code (stmt);
if (code != GIMPLE_LABEL && code != GIMPLE_TRY)
diff --git gcc/testsuite/c-c++-common/Wswitch-unreachable-2.c gcc/testsuite/c-c++-common/Wswitch-unreachable-2.c
index e69de29..8f57392 100644
--- gcc/testsuite/c-c++-common/Wswitch-unreachable-2.c
+++ gcc/testsuite/c-c++-common/Wswitch-unreachable-2.c
@@ -0,0 +1,18 @@
+/* PR c/71249 */
+/* { dg-do compile } */
+
+int
+f (int i)
+{
+ switch (i)
+ {
+ {
+ int j;
+ foo:
+ return i; /* { dg-bogus "statement will never be executed" } */
+ };
+ case 3:
+ goto foo;
+ }
+ return i;
+}
Marek