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[PATCH] Fix bogus warning with -Wimplicit-fallthrough (PR c/79152)
- From: Marek Polacek <polacek at redhat dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Cc: Jakub Jelinek <jakub at redhat dot com>
- Date: Fri, 20 Jan 2017 17:14:34 +0100
- Subject: [PATCH] Fix bogus warning with -Wimplicit-fallthrough (PR c/79152)
- Authentication-results: sourceware.org; auth=none
We already have code to handle
case 0:
foo ();
label:
bar ();
where we don't want to warn, but the code didn't handle consecutive non-case
labels. Thus fixed.
Bootstrapped/regtested on x86_64-linux, ok for trunk?
2017-01-20 Marek Polacek <polacek@redhat.com>
PR c/79152
* gimplify.c (should_warn_for_implicit_fallthrough): Handle consecutive
non-case labels.
* c-c++-common/Wimplicit-fallthrough-35.c: New test.
diff --git gcc/gimplify.c gcc/gimplify.c
index 2777a23..d382eea 100644
--- gcc/gimplify.c
+++ gcc/gimplify.c
@@ -1985,7 +1985,7 @@ should_warn_for_implicit_fallthrough (gimple_stmt_iterator *gsi_p, tree label)
if (FALLTHROUGH_LABEL_P (label))
return false;
- /* Don't warn for a non-case label followed by a statement:
+ /* Don't warn for non-case labels followed by a statement:
case 0:
foo ();
label:
@@ -1993,7 +1993,12 @@ should_warn_for_implicit_fallthrough (gimple_stmt_iterator *gsi_p, tree label)
as these are likely intentional. */
if (!case_label_p (&gimplify_ctxp->case_labels, label))
{
- gsi_next (&gsi);
+ tree l;
+ while (!gsi_end_p (gsi)
+ && gimple_code (gsi_stmt (gsi)) == GIMPLE_LABEL
+ && (l = gimple_label_label (as_a <glabel *> (gsi_stmt (gsi))))
+ && !case_label_p (&gimplify_ctxp->case_labels, l))
+ gsi_next (&gsi);
if (gsi_end_p (gsi) || gimple_code (gsi_stmt (gsi)) != GIMPLE_LABEL)
return false;
}
diff --git gcc/testsuite/c-c++-common/Wimplicit-fallthrough-35.c gcc/testsuite/c-c++-common/Wimplicit-fallthrough-35.c
index e69de29..9a0aba6 100644
--- gcc/testsuite/c-c++-common/Wimplicit-fallthrough-35.c
+++ gcc/testsuite/c-c++-common/Wimplicit-fallthrough-35.c
@@ -0,0 +1,61 @@
+/* PR c/79152 */
+/* { dg-do compile } */
+/* { dg-options "-Wimplicit-fallthrough" } */
+
+extern void foo (int);
+
+void
+f (int i)
+{
+ switch (i)
+ {
+ case 0:
+ foo (0);
+l1:
+ foo (1);
+ }
+
+ switch (i)
+ {
+ case 0:
+ foo (0);
+l2:;
+ }
+
+ switch (i)
+ {
+ case 0:
+ foo (0);
+l3:
+l4:
+ foo (1);
+ }
+
+ switch (i)
+ {
+ case 0:
+ foo (0);
+l5:
+l6:;
+ }
+
+ switch (i)
+ {
+ case 0:
+ foo (0); /* { dg-warning "statement may fall through" } */
+l7:
+l8:
+ case 1:
+ foo (1);
+ }
+
+ switch (i)
+ {
+ case 0:
+ foo (0); /* { dg-warning "statement may fall through" } */
+l9:
+ case 1:
+l10:
+ foo (1);
+ }
+}
Marek