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[C++ PATCH] Fix ICE with statement expression (PR c++/71728)
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Jason Merrill <jason at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Thu, 21 Jul 2016 18:09:19 +0200
- Subject: [C++ PATCH] Fix ICE with statement expression (PR c++/71728)
- Authentication-results: sourceware.org; auth=none
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
Hi!
It is true that parsing should make sure that GOTO_EXPRs (other than
break/continue) aren't allowed in constant expression contexts, but
potential_constant_expression_1 may be called (with tf_none) also
on arbitrary code either for warning purposes, or (very recent change)
also in cp_fully_fold, usually from maybe_constant_value.
So asserting they don't appear doesn't work.
Fixed thusly, alternatively we could assert that (flags & tf_error) == 0
before returning false.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk/6.2?
2016-07-21 Jakub Jelinek <jakub@redhat.com>
PR c++/71728
* constexpr.c (potential_constant_expression_1) <case GOTO_EXPR>:
Replace assert with test, return false if the goto isn't break
or continue. Formatting fix.
* g++.dg/other/pr71728.C: New test.
--- gcc/cp/constexpr.c.jj 2016-07-21 08:59:50.000000000 +0200
+++ gcc/cp/constexpr.c 2016-07-21 12:05:16.828618186 +0200
@@ -5289,10 +5289,12 @@ potential_constant_expression_1 (tree t,
case GOTO_EXPR:
{
tree *target = &TREE_OPERAND (t, 0);
- /* Gotos representing break and continue are OK; we should have
- rejected other gotos in parsing. */
- gcc_assert (breaks (target) || continues (target));
- return true;
+ /* Gotos representing break and continue are OK. */
+ if (breaks (target) || continues (target))
+ return true;
+ if (flags & tf_error)
+ error ("%<goto%> is not a constant-expression");
+ return false;
}
default:
@@ -5300,7 +5302,7 @@ potential_constant_expression_1 (tree t,
return false;
sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t)));
- gcc_unreachable();
+ gcc_unreachable ();
return false;
}
#undef RECUR
--- gcc/testsuite/g++.dg/other/pr71728.C.jj 2016-07-21 12:13:31.686461551 +0200
+++ gcc/testsuite/g++.dg/other/pr71728.C 2016-07-21 12:14:46.974524876 +0200
@@ -0,0 +1,11 @@
+// PR c++/71728
+// { dg-do compile }
+// { dg-options "-std=gnu++14 -Wall" }
+
+int
+foo ()
+{
+ if (({ goto test; test: 1; }) != 1)
+ return 1;
+ return 2;
+}
Jakub