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From: "oleg.endo@t-online.de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/49263] New: SH Target: underutilized "TST #imm, R0" instruction
Date: Wed, 01 Jun 2011 20:17:00 -0000 [thread overview]
Message-ID: <bug-49263-4@http.gcc.gnu.org/bugzilla/> (raw)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49263
Summary: SH Target: underutilized "TST #imm, R0" instruction
Product: gcc
Version: 4.6.1
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: target
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: oleg.endo@t-online.de
Created attachment 24411
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24411
test for various integer types and constant values 0...255
The "TST #imm, R0" instruction is a bit underutilized on SH targets. For some
bit patterns of the immediate constant it tries to extract the bits in question
by various means and test the result against zero/non-zero and misses the
straight forward instruction.
In particular:
* one single bit
* n contiguous bits starting at bit 0
When testing a byte against 0x80 it uses "CMP/PZ", which is as good as a "TST"
instruction (in terms of costs), so this is OK.
I've spotted this in version around 4.4. It still happens with 4.6 and the
following config:
Using built-in specs.
COLLECT_GCC=sh-elf-gcc
COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/sh-elf/4.6.1/lto-wrapper
Target: sh-elf
Configured with: ../gcc-4.6-20110527/configure --target=sh-elf
--prefix=/usr/local --enable-languages=c,c++ --enable-multilib --disable-libssp
--without-headers --disable-nls --disable-werror --enable-lto --with-newlib
--with-gnu-as --with-gnu-ld --with-system-zlib
Thread model: single
gcc version 4.6.1 20110527 (prerelease) (GCC)
next reply other threads:[~2011-06-01 20:17 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-01 20:17 oleg.endo@t-online.de [this message]
2011-06-01 20:42 ` [Bug target/49263] " oleg.endo@t-online.de
2011-06-12 23:12 ` kkojima at gcc dot gnu.org
2011-06-19 16:42 ` oleg.endo@t-online.de
2011-06-22 22:34 ` kkojima at gcc dot gnu.org
2011-06-26 22:31 ` oleg.endo@t-online.de
2011-06-27 5:15 ` kkojima at gcc dot gnu.org
2011-10-09 23:35 ` oleg.endo@t-online.de
2011-10-10 1:32 ` kkojima at gcc dot gnu.org
2011-10-10 23:48 ` oleg.endo@t-online.de
2011-10-11 1:47 ` kkojima at gcc dot gnu.org
2011-10-13 22:55 ` oleg.endo@t-online.de
2011-10-14 23:06 ` kkojima at gcc dot gnu.org
2011-10-15 2:33 ` kkojima at gcc dot gnu.org
2011-11-20 14:20 ` oleg.endo@t-online.de
2011-12-29 1:09 ` oleg.endo@t-online.de
2012-02-26 16:28 ` olegendo at gcc dot gnu.org
2012-02-26 23:29 ` olegendo at gcc dot gnu.org
2012-08-27 19:52 ` olegendo at gcc dot gnu.org
2012-10-28 22:02 ` olegendo at gcc dot gnu.org
2012-10-31 13:47 ` olegendo at gcc dot gnu.org
2013-12-08 13:47 ` olegendo at gcc dot gnu.org
2013-12-17 12:37 ` olegendo at gcc dot gnu.org
2014-12-30 18:45 ` olegendo at gcc dot gnu.org
2015-01-24 13:05 ` olegendo at gcc dot gnu.org
2015-01-26 23:57 ` olegendo at gcc dot gnu.org
2023-05-12 11:46 ` klepikov.alex+bugs at gmail dot com
2023-05-23 12:34 ` klepikov.alex+bugs at gmail dot com
2023-05-23 12:35 ` klepikov.alex+bugs at gmail dot com
2023-05-23 19:05 ` olegendo at gcc dot gnu.org
2023-05-24 11:40 ` klepikov.alex+bugs at gmail dot com
2023-05-24 11:57 ` olegendo at gcc dot gnu.org
2023-05-24 13:34 ` klepikov.alex+bugs at gmail dot com
2023-05-24 15:00 ` olegendo at gcc dot gnu.org
2023-05-25 17:53 ` klepikov.alex+bugs at gmail dot com
2023-05-25 21:32 ` olegendo at gcc dot gnu.org
2023-05-26 12:03 ` klepikov.alex+bugs at gmail dot com
2023-05-26 17:44 ` olegendo at gcc dot gnu.org
2023-05-28 10:24 ` klepikov.alex+bugs at gmail dot com
2023-05-28 10:48 ` olegendo at gcc dot gnu.org
2023-05-29 14:54 ` klepikov.alex+bugs at gmail dot com
2023-05-30 1:48 ` egallager at gcc dot gnu.org
2023-05-30 1:56 ` olegendo at gcc dot gnu.org
2023-05-30 12:42 ` klepikov.alex+bugs at gmail dot com
2023-05-30 19:57 ` olegendo at gcc dot gnu.org
2023-05-30 20:00 ` olegendo at gcc dot gnu.org
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