This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug debug/43516] [4.5 Regression] "-fcompare-debug failure" at -O2
- From: "jakub at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 26 Mar 2010 10:42:02 -0000
- Subject: [Bug debug/43516] [4.5 Regression] "-fcompare-debug failure" at -O2
- References: <bug-43516-14164@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #10 from jakub at gcc dot gnu dot org 2010-03-26 10:42 -------
In particular, for -g0 the alias set of that unsigned 1 bit type actually
changes.
This is on the #c1 testcase, with
-g -fcompare-debug=-gtoggle pr43516.c -O2 -fdump-final-insns=/tmp/1
resp.
-g0 -fcompare-debug=-gtoggle pr43516.c -O2 -fdump-final-insns=/tmp/2
Putting a breakpoint on new_alias_set when it returns 41 or more, when it
returns 41 in the backtrace is first get_alias_set for the signed 1 bit type
that c_common_signed_type returned, then 2 frames up get_alias_set for the
problematic unsigned 1 bit type. In -g0 case a few get_alias_set calls on this
unsigned 1 bit type suddenly c_common_signed_type returns a different type,
which doesn't have alias set computed, while for -g it doesn't.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43516