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[Bug target/30770] [4.3 regression] BOOT_CFLAGS="-O2 -g -mtune=nocona" miscompiled the stage 3 compiler
- From: "ubizjak at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 24 Feb 2007 19:09:52 -0000
- Subject: [Bug target/30770] [4.3 regression] BOOT_CFLAGS="-O2 -g -mtune=nocona" miscompiled the stage 3 compiler
- References: <bug-30770-682@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #5 from ubizjak at gmail dot com 2007-02-24 19:09 -------
(In reply to comment #2)
> I have verified that revision 119252:
>
> http://gcc.gnu.org/ml/gcc-cvs/2006-11/msg00907.html
> breaks -mtune=nocona. Jan, can you take a look? Thanks.
Something is still wrong with unrolled_loop stringop handling.
Patch at http://gcc.gnu.org/ml/gcc-patches/2007-02/msg01937.html and the
following patch that disables unrolled loop stringops (for nocona) bootstraps
OK for -mtune=nocona. This applies to -march=athlon64 as well.
Index: i386.c
===================================================================
--- i386.c (revision 122286)
+++ i386.c (working copy)
@@ -789,10 +789,10 @@
COSTS_N_INSNS (44), /* cost of FSQRT instruction. */
{{libcall, {{12, loop_1_byte}, {-1, rep_prefix_4_byte}}},
{libcall, {{32, loop}, {20000, rep_prefix_8_byte},
- {100000, unrolled_loop}, {-1, libcall}}}},
+ /*{100000, unrolled_loop},*/ {-1, libcall}}}},
{{libcall, {{6, loop_1_byte}, {48, loop}, {20480, rep_prefix_4_byte},
{-1, libcall}}},
- {libcall, {{24, loop}, {64, unrolled_loop},
+ {libcall, {{24, loop}, /*{64, unrolled_loop},*/
{8192, rep_prefix_8_byte}, {-1, libcall}}}}
};
--
ubizjak at gmail dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ubizjak at gmail dot com
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2007-02-24 19:09:51
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30770