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* [Bug target/26949] New: [4.2 regression] worse code generated for -march=pentium4
@ 2006-03-30 18:26 dann at godzilla dot ics dot uci dot edu
2006-06-04 19:36 ` [Bug target/26949] " jsm28 at gcc dot gnu dot org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: dann at godzilla dot ics dot uci dot edu @ 2006-03-30 18:26 UTC (permalink / raw)
To: gcc-bugs
Compiling the code in PR26944 with -O2 -march=pentium4 -fno-tree-ch
generates this for the loop:
.L3:
movl %esi, -4(%eax)
addl $1, %edx
addl $4, %eax
cmpl -16(%ebp), %edx <----- note an extra memory access here
jle .L3
compiling for -march=i686 (or even just adding -fomit-frame-pointer) generates:
.L3:
addl $1, %ecx
movl %ebx, -4(%edx)
addl $4, %edx
cmpl %eax, %ecx <---- no memory access here
jle .L3
The above problem does not happen with gcc-4.0.3 or 4.1.0
--
Summary: [4.2 regression] worse code generated for -
march=pentium4
Product: gcc
Version: 4.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: dann at godzilla dot ics dot uci dot edu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26949
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/26949] [4.2 regression] worse code generated for -march=pentium4
2006-03-30 18:26 [Bug target/26949] New: [4.2 regression] worse code generated for -march=pentium4 dann at godzilla dot ics dot uci dot edu
@ 2006-06-04 19:36 ` jsm28 at gcc dot gnu dot org
2006-06-04 19:59 ` mmitchel at gcc dot gnu dot org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: jsm28 at gcc dot gnu dot org @ 2006-06-04 19:36 UTC (permalink / raw)
To: gcc-bugs
--
jsm28 at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |4.2.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26949
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/26949] [4.2 regression] worse code generated for -march=pentium4
2006-03-30 18:26 [Bug target/26949] New: [4.2 regression] worse code generated for -march=pentium4 dann at godzilla dot ics dot uci dot edu
2006-06-04 19:36 ` [Bug target/26949] " jsm28 at gcc dot gnu dot org
@ 2006-06-04 19:59 ` mmitchel at gcc dot gnu dot org
2006-07-06 8:23 ` uros at kss-loka dot si
2006-07-06 8:24 ` uros at kss-loka dot si
3 siblings, 0 replies; 5+ messages in thread
From: mmitchel at gcc dot gnu dot org @ 2006-06-04 19:59 UTC (permalink / raw)
To: gcc-bugs
--
mmitchel at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P2
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26949
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/26949] [4.2 regression] worse code generated for -march=pentium4
2006-03-30 18:26 [Bug target/26949] New: [4.2 regression] worse code generated for -march=pentium4 dann at godzilla dot ics dot uci dot edu
2006-06-04 19:36 ` [Bug target/26949] " jsm28 at gcc dot gnu dot org
2006-06-04 19:59 ` mmitchel at gcc dot gnu dot org
@ 2006-07-06 8:23 ` uros at kss-loka dot si
2006-07-06 8:24 ` uros at kss-loka dot si
3 siblings, 0 replies; 5+ messages in thread
From: uros at kss-loka dot si @ 2006-07-06 8:23 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from uros at kss-loka dot si 2006-07-06 08:23 -------
This problem appears to be fixed in gcc version 4.2.0 20060705 (experimental).
The generated asm for the loop is now:
-O2 -march=pentium4 -fno-tree-ch:
jmp .L2
.L3:
movl %esi, -4(%edx)
addl $1, %eax
.L2:
addl $4, %edx
cmpl %ecx, %eax
jle .L3
-O2 -march=i686 -fno-tree-ch:
jmp .L2
.p2align 4,,7
.L3:
movl %ebx, -4(%ecx)
addl $1, %edx
.L2:
addl $4, %ecx
cmpl %eax, %edx
jle .L3
Closing the bug as FIXED.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26949
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/26949] [4.2 regression] worse code generated for -march=pentium4
2006-03-30 18:26 [Bug target/26949] New: [4.2 regression] worse code generated for -march=pentium4 dann at godzilla dot ics dot uci dot edu
` (2 preceding siblings ...)
2006-07-06 8:23 ` uros at kss-loka dot si
@ 2006-07-06 8:24 ` uros at kss-loka dot si
3 siblings, 0 replies; 5+ messages in thread
From: uros at kss-loka dot si @ 2006-07-06 8:24 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from uros at kss-loka dot si 2006-07-06 08:24 -------
Closing it for real...
--
uros at kss-loka dot si changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |FIXED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26949
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2006-07-06 8:24 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2006-03-30 18:26 [Bug target/26949] New: [4.2 regression] worse code generated for -march=pentium4 dann at godzilla dot ics dot uci dot edu
2006-06-04 19:36 ` [Bug target/26949] " jsm28 at gcc dot gnu dot org
2006-06-04 19:59 ` mmitchel at gcc dot gnu dot org
2006-07-06 8:23 ` uros at kss-loka dot si
2006-07-06 8:24 ` uros at kss-loka dot si
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