[Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45223 --- Comment #9 from Richard Biener --- But this but is about non-MEMs while the fixes were involving only memory ops IIRC.
[Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45223 Andrew Pinski 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 --- So I think this has been fully fixed for GCC 12 via r12-2254 (aka PR 101373).
[Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45223 Bug 45223 depends on bug 42108, which changed state. Bug 42108 Summary: [4.9 Regression] 50% performance regression https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42108 What|Removed |Added Status|ASSIGNED|RESOLVED Resolution|--- |FIXED
[Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop
--- 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
[Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop
--- 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
[Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop
--- 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
[Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop
--- 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:
callfoo
...
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
[Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop
--- 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|-00-00 00:00:00 |2010-08-07 10:57:54 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45223
[Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop
--- 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
[Bug rtl-optimization/45223] RTL PRE GCSE pass hoists trapping insn out of loop
--- 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
