[Bug c++/84724] [7/8 Regression] internal compiler error: in single_succ_edge, at basic-block.h:339 with a declaration of __builtin_trap
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84724 --- Comment #5 from Jakub Jelinek --- Author: jakub Date: Fri Mar 9 18:01:22 2018 New Revision: 258391 URL: https://gcc.gnu.org/viewcvs?rev=258391=gcc=rev Log: PR c++/84724 * decl.c (duplicate_decls): Don't override __* prefixed builtins except for __[^b]*_chk, instead issue permerror and for -fpermissive also a note and return olddecl. * g++.dg/ext/pr84724.C: New test. Added: trunk/gcc/testsuite/g++.dg/ext/pr84724-1.C trunk/gcc/testsuite/g++.dg/ext/pr84724-2.C trunk/gcc/testsuite/g++.dg/ext/pr84724-3.C Modified: trunk/gcc/cp/ChangeLog trunk/gcc/cp/decl.c trunk/gcc/testsuite/ChangeLog
[Bug c++/84724] [7/8 Regression] internal compiler error: in single_succ_edge, at basic-block.h:339 with a declaration of __builtin_trap
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84724 --- Comment #4 from Jakub Jelinek --- Created attachment 43595 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43595=edit gcc8-pr84724.patch Untested fix.
[Bug c++/84724] [7/8 Regression] internal compiler error: in single_succ_edge, at basic-block.h:339 with a declaration of __builtin_trap
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84724 Jakub Jelinek changed: What|Removed |Added CC||jakub at gcc dot gnu.org, ||jason at gcc dot gnu.org --- Comment #3 from Jakub Jelinek --- The C FE has quite a lot of code in this case, e.g. match_builtin_function_types, which the C++ FE doesn't seem to have, and indeed the C FE leaves the __builtin_trap decl untouched after warning, while the C++ FE changes it. The ICE in this case isn't caused by a mismatch between __builtin_trap () return type, but rather the lack of noreturn attribute on the new decl. Though I'm sure that redefining similar way many other builtins that GCC emits on its own or expects a particular arguments or return types will cause many other ICEs.
[Bug c++/84724] [7/8 Regression] internal compiler error: in single_succ_edge, at basic-block.h:339 with a declaration of __builtin_trap
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84724 Richard Biener changed: What|Removed |Added Priority|P3 |P2 Target Milestone|--- |7.4 --- Comment #2 from Richard Biener --- Yeah. Or rather the FEs shouldn't clobber the builtin decls (_not_ merge into them) so that when the ME looks up decls for them they never pick up user decls. Similar issues for builtin folding if the folded-to builtin is misdeclared.
[Bug c++/84724] [7/8 Regression] internal compiler error: in single_succ_edge, at basic-block.h:339 with a declaration of __builtin_trap
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84724
Martin Sebor changed:
What|Removed |Added
Status|UNCONFIRMED |NEW
Last reconfirmed||2018-03-06
CC||msebor at gcc dot gnu.org
Known to work||6.4.0
Summary|internal compiler error: in |[7/8 Regression] internal
|single_succ_edge, at|compiler error: in
|basic-block.h:339 |single_succ_edge, at
||basic-block.h:339 with a
||declaration of
||__builtin_trap
Ever confirmed|0 |1
Known to fail||7.3.0, 8.0
--- Comment #1 from Martin Sebor ---
Confirmed with r244114 (gcc 7.0.0) as the first revision to ICE:
r244114 | jakub | 2017-01-05 16:14:19 -0500 (Thu, 05 Jan 2017) | 12 lines
PR tree-optimization/71016
Prior to that GCC accepted the test case (with -fpermissive):
t.C:2:5: warning: new declaration ‘int __builtin_trap()’ ambiguates built-in
declaration ‘void __builtin_trap()’ [-Wbuiltin-declaration-mismatch]
int __builtin_trap();
^~
t.C: In function ‘int a()’:
t.C:6:9: warning: invalid conversion from ‘int*’ to ‘int’ [-fpermissive]
int c();
^~
A simpler test case is
int __builtin_trap ();
int a (int i)
{
const char *p = i < 0 ? 0 : "";
return *p;
}
The trouble seems to be that __builtin_trap is expected not to return but the
extern C++ declaration in the program says otherwise and overrides the
built-in. I'd say re-declarations of built-ins that GCC itself depends
on/makes assumptions about should be rejected with a hard error.
