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* [Bug target/42516] New: [m68k] Suboptimal halfword swap on coldfire
@ 2009-12-27 16:53 nizze86 at hotmail dot com
2009-12-27 17:19 ` [Bug target/42516] " schwab at linux-m68k dot org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: nizze86 at hotmail dot com @ 2009-12-27 16:53 UTC (permalink / raw)
To: gcc-bugs
When compiling the following function for a coldfire target, such as mcf5249:
(using the following command line m68k-elf-gcc hswap.c -mcpu=5249 -S -O2)
unsigned hswap(unsigned x)
{
return (x << 16) | (x >> 16);
}
gcc produces:
hswap:
link.w %fp,#0
move.l 8(%fp),%d1
move.l %d1,%d0
clr.w %d0
swap %d0
swap %d1
clr.w %d1
or.l %d1,%d0
unlk %fp
rts
Optimization level affects only instr ordering.
the same function compiled for 68020
(using the following command line m68k-elf-gcc hswap.c -mcpu=68020 -S -O2)
hswap:
link.w %fp,#0
move.l 8(%fp),%d0
swap %d0
unlk %fp
rts
which is valid code for the coldfire target too and much smaller and faster
this is using gcc 4.4.2 configured with
--enable-languages=c --disable-libssp --with-arch=cf --with-cpu=5249
the same behaviour is present in gcc 3.4.6 too.
--
Summary: [m68k] Suboptimal halfword swap on coldfire
Product: gcc
Version: 4.4.2
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: nizze86 at hotmail dot com
GCC host triplet: amd64-unknown-linux
GCC target triplet: m68k-elf
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42516
^ permalink raw reply [flat|nested] 5+ messages in thread* [Bug target/42516] [m68k] Suboptimal halfword swap on coldfire 2009-12-27 16:53 [Bug target/42516] New: [m68k] Suboptimal halfword swap on coldfire nizze86 at hotmail dot com @ 2009-12-27 17:19 ` schwab at linux-m68k dot org 2009-12-27 20:05 ` mkuvyrkov at gcc dot gnu dot org ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: schwab at linux-m68k dot org @ 2009-12-27 17:19 UTC (permalink / raw) To: gcc-bugs ------- Comment #1 from schwab at linux-m68k dot org 2009-12-27 17:19 ------- This is part of the rotlsi3 pattern which is disabled for coldfire since it does not have rotate insns. -- schwab at linux-m68k dot org changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Ever Confirmed|0 |1 GCC host triplet|amd64-unknown-linux | GCC target triplet|m68k-elf |m68k-*-* Last reconfirmed|0000-00-00 00:00:00 |2009-12-27 17:19:24 date| | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42516 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/42516] [m68k] Suboptimal halfword swap on coldfire 2009-12-27 16:53 [Bug target/42516] New: [m68k] Suboptimal halfword swap on coldfire nizze86 at hotmail dot com 2009-12-27 17:19 ` [Bug target/42516] " schwab at linux-m68k dot org @ 2009-12-27 20:05 ` mkuvyrkov at gcc dot gnu dot org 2009-12-30 23:04 ` schwab at gcc dot gnu dot org 2009-12-30 23:05 ` schwab at linux-m68k dot org 3 siblings, 0 replies; 5+ messages in thread From: mkuvyrkov at gcc dot gnu dot org @ 2009-12-27 20:05 UTC (permalink / raw) To: gcc-bugs ------- Comment #2 from mkuvyrkov at gcc dot gnu dot org 2009-12-27 20:05 ------- Thanks for the bug report. I've posted a proposed patch in http://gcc.gnu.org/ml/gcc-patches/2009-12/msg01142.html. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42516 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/42516] [m68k] Suboptimal halfword swap on coldfire 2009-12-27 16:53 [Bug target/42516] New: [m68k] Suboptimal halfword swap on coldfire nizze86 at hotmail dot com 2009-12-27 17:19 ` [Bug target/42516] " schwab at linux-m68k dot org 2009-12-27 20:05 ` mkuvyrkov at gcc dot gnu dot org @ 2009-12-30 23:04 ` schwab at gcc dot gnu dot org 2009-12-30 23:05 ` schwab at linux-m68k dot org 3 siblings, 0 replies; 5+ messages in thread From: schwab at gcc dot gnu dot org @ 2009-12-30 23:04 UTC (permalink / raw) To: gcc-bugs ------- Comment #3 from schwab at gcc dot gnu dot org 2009-12-30 23:03 ------- Subject: Bug 42516 Author: schwab Date: Wed Dec 30 23:03:46 2009 New Revision: 155527 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=155527 Log: PR target/42516 * config/m68k/m68k.md (rotlsi_16): New insn. Modified: trunk/gcc/ChangeLog trunk/gcc/config/m68k/m68k.md -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42516 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/42516] [m68k] Suboptimal halfword swap on coldfire 2009-12-27 16:53 [Bug target/42516] New: [m68k] Suboptimal halfword swap on coldfire nizze86 at hotmail dot com ` (2 preceding siblings ...) 2009-12-30 23:04 ` schwab at gcc dot gnu dot org @ 2009-12-30 23:05 ` schwab at linux-m68k dot org 3 siblings, 0 replies; 5+ messages in thread From: schwab at linux-m68k dot org @ 2009-12-30 23:05 UTC (permalink / raw) To: gcc-bugs ------- Comment #4 from schwab at linux-m68k dot org 2009-12-30 23:04 ------- Fixed. -- schwab at linux-m68k dot org changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution| |FIXED Target Milestone|--- |4.5.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42516 ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2009-12-30 23:05 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2009-12-27 16:53 [Bug target/42516] New: [m68k] Suboptimal halfword swap on coldfire nizze86 at hotmail dot com 2009-12-27 17:19 ` [Bug target/42516] " schwab at linux-m68k dot org 2009-12-27 20:05 ` mkuvyrkov at gcc dot gnu dot org 2009-12-30 23:04 ` schwab at gcc dot gnu dot org 2009-12-30 23:05 ` schwab at linux-m68k dot org
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