This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug rtl-optimization/34773] [4.3 regression] miscompilation of vfprintf_r
- From: "hp at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 31 Jan 2008 05:08:02 -0000
- Subject: [Bug rtl-optimization/34773] [4.3 regression] miscompilation of vfprintf_r
- References: <bug-34773-507@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #5 from hp at gcc dot gnu dot org 2008-01-31 05:08 -------
The bug is that fwprop1 adds a REG_EQUAL note to an insn with a REG_RETVAL,
confusing delete_trivially_dead_insns into thinking that the REG_EQUAL note
refers to the while libcall and that a simplification thereof can make the
libcall-equivalence sequence redundant. The combination is described that way
in optabs.c:emit_no_conflict_block, so the assumption appears valid. Testing a
patch that teaches try_fwprop_subst about this special case. Places in gcse.c
look suspicious too, perhaps also elsewhere.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34773