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* [Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop [not found] <bug-45223-4@http.gcc.gnu.org/bugzilla/> @ 2021-10-11 3:44 ` pinskia at gcc dot gnu.org 2021-10-11 9:11 ` rguenth at gcc dot gnu.org 1 sibling, 0 replies; 9+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-10-11 3:44 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45223 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- See Also| |https://gcc.gnu.org/bugzill | |a/show_bug.cgi?id=101373, | |https://gcc.gnu.org/bugzill | |a/show_bug.cgi?id=101868 --- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> --- So I think this has been fully fixed for GCC 12 via r12-2254 (aka PR 101373). ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop [not found] <bug-45223-4@http.gcc.gnu.org/bugzilla/> 2021-10-11 3:44 ` [Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop pinskia at gcc dot gnu.org @ 2021-10-11 9:11 ` rguenth at gcc dot gnu.org 1 sibling, 0 replies; 9+ messages in thread From: rguenth at gcc dot gnu.org @ 2021-10-11 9:11 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45223 --- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> --- But this but is about non-MEMs while the fixes were involving only memory ops IIRC. ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug rtl-optimization/45223] New: RTL PRE GCSE pass hoists trapping insn out of loop
@ 2010-08-07 8:24 ubizjak at gmail dot com
2010-08-07 8:34 ` [Bug rtl-optimization/45223] " ubizjak at gmail dot com
` (6 more replies)
0 siblings, 7 replies; 9+ messages in thread
From: ubizjak at gmail dot com @ 2010-08-07 8:24 UTC (permalink / raw)
To: gcc-bugs
This is a follow-up from PR38819 which partially fixes this problem. The
problem remains in RTL optimization passes, and can be triggered on targets
that implement modulo instruction in the hardware (i.e. moxie-elf).
The testcase from PR38819 compiles with -O2 to:
main:
push $sp, $r6
push $sp, $r7
push $sp, $r8
push $sp, $r9
push $sp, $r10
push $sp, $r11
dec $sp, 24
lda.l $r7, a
lda.l $r0, b
xor $r6, $r6
ldi.l $r11, foo
> mod.l $r7, $r0
ldi.l $r10, 8
ldi.l $r8, 99
jmpa .L4
.L3:
...
Since b is initialized to zero, mod.l instruction traps.
--
Summary: RTL PRE GCSE pass hoists trapping insn out of loop
Product: gcc
Version: 4.5.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: ubizjak at gmail dot com
GCC target triplet: moxie-elf
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45223
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop 2010-08-07 8:24 [Bug rtl-optimization/45223] New: " ubizjak at gmail dot com @ 2010-08-07 8:34 ` ubizjak at gmail dot com 2010-08-07 8:40 ` ubizjak at gmail dot com ` (5 subsequent siblings) 6 siblings, 0 replies; 9+ messages in thread From: ubizjak at gmail dot com @ 2010-08-07 8:34 UTC (permalink / raw) To: gcc-bugs ------- Comment #1 from ubizjak at gmail dot com 2010-08-07 08:33 ------- Following patch fixes this problem: Index: gcse.c =================================================================== --- gcse.c (revision 162975) +++ gcse.c (working copy) @@ -1693,7 +1693,7 @@ compute_hash_table_work (struct hash_tab /* The next pass builds the hash table. */ FOR_BB_INSNS (current_bb, insn) - if (INSN_P (insn)) + if (INSN_P (insn) && !may_trap_p (PATTERN (insn))) hash_scan_insn (insn, table); } main: push $sp, $r6 push $sp, $r7 push $sp, $r8 push $sp, $r9 push $sp, $r10 push $sp, $r11 dec $sp, 28 lda.l $r0, a sto.l -28($fp), $r0 lda.l $r11, b xor $r6, $r6 ldi.l $r10, foo ldi.l $r8, 8 ldi.l $r7, 99 jmpa .L4 .L3: lda.l $r1, r ldo.l $r0, -28($fp) mod.l $r0, $r11 add.l $r0, $r1 add.l $r0, $r6 sta.l r, $r0 inc $r6, 1 cmp $r6, $r7 bgt .L7 .L4: jsr $r10 lda.l $r0, x cmp $r0, $r8 bne .L3 inc $r6, 1 lda.l $r1, r ldo.l $r0, -28($fp) > mod.l $r0, $r11 add.l $r0, $r1 add.l $r0, $r6 sta.l r, $r0 inc $r6, 1 cmp $r6, $r7 ble .L4 .L7: jsra abort In a general case, I guess that if it can be proved that denominator can't be zero we can still hoist mod.l out of the loop. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45223 ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop 2010-08-07 8:24 [Bug rtl-optimization/45223] New: " ubizjak at gmail dot com 2010-08-07 8:34 ` [Bug rtl-optimization/45223] " ubizjak at gmail dot com @ 2010-08-07 8:40 ` ubizjak at gmail dot com 2010-08-07 10:58 ` steven at gcc dot gnu dot org ` (4 subsequent siblings) 6 siblings, 0 replies; 9+ messages in thread From: ubizjak at gmail dot com @ 2010-08-07 8:40 UTC (permalink / raw) To: gcc-bugs ------- Comment #2 from ubizjak at gmail dot com 2010-08-07 08:40 ------- Ugh, with a bit changed testcase: --cut here-- extern void exit (int); extern void abort (void); volatile float a = 1; volatile float b = 0; volatile int x = 2; volatile signed int r = 8; void __attribute__((noinline)) foo (void) { exit (0); } int main (void) { float si1 = a; float si2 = b; int i; for (i = 0; i < 100; ++i) { foo (); if (x == 8) i++; r += i + (int) (si1 / si2); } abort (); } --cut here-- -O2 on x86_64-pc-linux-gnu: main: pushq %rbx xorl %ebx, %ebx subq $16, %rsp movss a(%rip), %xmm0 movss %xmm0, 12(%rsp) movss b(%rip), %xmm0 movss 12(%rsp), %xmm1 > divss %xmm0, %xmm1 movss %xmm1, 12(%rsp) .L4: call foo ... I hope that Ariane-5 is safe [1] ;) [1] http://en.wikipedia.org/wiki/Ariane_5_Flight_501 -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45223 ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop 2010-08-07 8:24 [Bug rtl-optimization/45223] New: " ubizjak at gmail dot com 2010-08-07 8:34 ` [Bug rtl-optimization/45223] " ubizjak at gmail dot com 2010-08-07 8:40 ` ubizjak at gmail dot com @ 2010-08-07 10:58 ` steven at gcc dot gnu dot org 2010-08-07 11:26 ` ubizjak at gmail dot com ` (3 subsequent siblings) 6 siblings, 0 replies; 9+ messages in thread From: steven at gcc dot gnu dot org @ 2010-08-07 10:58 UTC (permalink / raw) To: gcc-bugs ------- Comment #3 from steven at gcc dot gnu dot org 2010-08-07 10:57 ------- Patch of comment #1 loops obviously OK to me. We shouldn't want to move trapping insns in any case that I can think of. -- steven at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Ever Confirmed|0 |1 Last reconfirmed|0000-00-00 00:00:00 |2010-08-07 10:57:54 date| | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45223 ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop 2010-08-07 8:24 [Bug rtl-optimization/45223] New: " ubizjak at gmail dot com ` (2 preceding siblings ...) 2010-08-07 10:58 ` steven at gcc dot gnu dot org @ 2010-08-07 11:26 ` ubizjak at gmail dot com 2010-08-07 15:27 ` ubizjak at gmail dot com ` (2 subsequent siblings) 6 siblings, 0 replies; 9+ messages in thread From: ubizjak at gmail dot com @ 2010-08-07 11:26 UTC (permalink / raw) To: gcc-bugs ------- Comment #4 from ubizjak at gmail dot com 2010-08-07 11:26 ------- (In reply to comment #3) > Patch of comment #1 loops obviously OK to me. We shouldn't want to move > trapping insns in any case that I can think of. OK, will post patch to gcc-patches after regression test. -- ubizjak at gmail dot com changed: What |Removed |Added ---------------------------------------------------------------------------- AssignedTo|unassigned at gcc dot gnu |ubizjak at gmail dot com |dot org | Status|NEW |ASSIGNED Last reconfirmed|2010-08-07 10:57:54 |2010-08-07 11:26:29 date| | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45223 ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop 2010-08-07 8:24 [Bug rtl-optimization/45223] New: " ubizjak at gmail dot com ` (3 preceding siblings ...) 2010-08-07 11:26 ` ubizjak at gmail dot com @ 2010-08-07 15:27 ` ubizjak at gmail dot com 2010-08-12 14:46 ` ubizjak at gmail dot com 2010-09-04 10:03 ` ubizjak at gmail dot com 6 siblings, 0 replies; 9+ messages in thread From: ubizjak at gmail dot com @ 2010-08-07 15:27 UTC (permalink / raw) To: gcc-bugs ------- Comment #5 from ubizjak at gmail dot com 2010-08-07 15:27 ------- Patch at [1]. [1] http://gcc.gnu.org/ml/gcc-patches/2010-08/msg00553.html -- ubizjak at gmail dot com changed: What |Removed |Added ---------------------------------------------------------------------------- URL| |http://gcc.gnu.org/ml/gcc- | |patches/2010- | |08/msg00553.html http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45223 ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop 2010-08-07 8:24 [Bug rtl-optimization/45223] New: " ubizjak at gmail dot com ` (4 preceding siblings ...) 2010-08-07 15:27 ` ubizjak at gmail dot com @ 2010-08-12 14:46 ` ubizjak at gmail dot com 2010-09-04 10:03 ` ubizjak at gmail dot com 6 siblings, 0 replies; 9+ messages in thread From: ubizjak at gmail dot com @ 2010-08-12 14:46 UTC (permalink / raw) To: gcc-bugs ------- Comment #6 from ubizjak at gmail dot com 2010-08-12 14:46 ------- Ouch, "Here are the ration of before and after on Intel Core i7. Gzip slowed down by 10 to 20%." [1] Richi says: "The fix is to teach LIM to do conditional invariant motion." Probably also related to PR42108 catch-all PR. [1] http://gcc.gnu.org/ml/gcc-patches/2010-08/msg00771.html [2] http://gcc.gnu.org/ml/gcc-patches/2010-08/msg00884.html -- ubizjak at gmail dot com changed: What |Removed |Added ---------------------------------------------------------------------------- BugsThisDependsOn| |42108 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45223 ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop 2010-08-07 8:24 [Bug rtl-optimization/45223] New: " ubizjak at gmail dot com ` (5 preceding siblings ...) 2010-08-12 14:46 ` ubizjak at gmail dot com @ 2010-09-04 10:03 ` ubizjak at gmail dot com 6 siblings, 0 replies; 9+ messages in thread From: ubizjak at gmail dot com @ 2010-09-04 10:03 UTC (permalink / raw) To: gcc-bugs ------- Comment #7 from ubizjak at gmail dot com 2010-09-04 10:03 ------- Unassigning... -- ubizjak at gmail dot com changed: What |Removed |Added ---------------------------------------------------------------------------- AssignedTo|ubizjak at gmail dot com |unassigned at gcc dot gnu | |dot org Status|ASSIGNED |NEW http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45223 ^ permalink raw reply [flat|nested] 9+ messages in thread
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2021-10-11 3:44 ` [Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop pinskia at gcc dot gnu.org
2021-10-11 9:11 ` rguenth at gcc dot gnu.org
2010-08-07 8:24 [Bug rtl-optimization/45223] New: " ubizjak at gmail dot com
2010-08-07 8:34 ` [Bug rtl-optimization/45223] " ubizjak at gmail dot com
2010-08-07 8:40 ` ubizjak at gmail dot com
2010-08-07 10:58 ` steven at gcc dot gnu dot org
2010-08-07 11:26 ` ubizjak at gmail dot com
2010-08-07 15:27 ` ubizjak at gmail dot com
2010-08-12 14:46 ` ubizjak at gmail dot com
2010-09-04 10:03 ` ubizjak at gmail dot com
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