[Bug tree-optimization/39839] [4.3/4.4/4.5 regression] loop invariant motion causes stack spill
--- Comment #8 from rguenth at gcc dot gnu dot org 2010-01-02 11:18 --- You may also want to try -fsched-pressure -fschedule-insns which is new in GCC 4.5 and might decrease register pressure (no idea if it ever moves things into loops though - the haifa scheduler might not consider it a region to work on). -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39839
[Bug tree-optimization/39839] [4.3/4.4/4.5 regression] loop invariant motion causes stack spill
--- Comment #7 from steven at gcc dot gnu dot org 2010-01-02 00:49 ---
With "GCC: (GNU) 4.5.0 20090808 (experimental) [trunk revision 150579]" I get:
.arch armv5te
.fpu softvfp
.eabi_attribute 20, 1
.eabi_attribute 21, 1
.eabi_attribute 23, 3
.eabi_attribute 24, 1
.eabi_attribute 25, 1
.eabi_attribute 26, 1
.eabi_attribute 30, 4
.eabi_attribute 18, 4
.code 16
.file "t.c"
.text
.align 1
.global test
.code 16
.thumb_func
.type test, %function
test:
push{r3, r4, r5, r6, r7, lr}
ldr r3, .L7
ldr r5, .L7+4
.LPIC0:
add r3, pc
add r5, r3, r5
mov r7, r5
mov r4, r0
ldr r6, [r0]
add r7, r7, #8
b .L2
.L4:
ldr r1, [r4, #4]
ldrbr3, [r1]
cmp r3, #0
bne .L5
mov r3, r5
b .L3
.L5:
add r3, r5, #4
.L3:
add r1, r1, r6
mov r0, r7
mov r2, r6
bl func
ldr r3, [r4]
sub r3, r3, #1
str r3, [r4]
.L2:
ldr r3, [r4]
cmp r3, #0
bge .L4
@ sp needed for prologue
pop {r3, r4, r5, r6, r7, pc}
.L8:
.align 2
.L7:
.word _GLOBAL_OFFSET_TABLE_-(.LPIC0+4)
.word .LANCHOR0(GOTOFF)
.size test, .-test
.section.rodata
.set.LANCHOR0,. + 0
.LC0:
.ascii "xyz\000"
.LC1:
.ascii "pqr\000"
.LC2:
.ascii "abcde\000"
.ident "GCC: (GNU) 4.5.0 20090808 (experimental) [trunk revision
150579]"
I have no idea whether that is better or worse. Alexander, could you give this
a look please?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39839
[Bug tree-optimization/39839] [4.3/4.4/4.5 regression] loop invariant motion causes stack spill
--- Comment #6 from rguenth at gcc dot gnu dot org 2009-08-04 12:30 --- GCC 4.3.4 is being released, adjusting target milestone. -- rguenth at gcc dot gnu dot org changed: What|Removed |Added Target Milestone|4.3.4 |4.3.5 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39839
[Bug tree-optimization/39839] [4.3/4.4/4.5 regression] loop invariant motion causes stack spill
--- Comment #5 from steven at gcc dot gnu dot org 2009-06-22 16:29 --- How is this different from bug 39837? -- steven at gcc dot gnu dot org changed: What|Removed |Added OtherBugsDependingO||16996 nThis|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39839
[Bug tree-optimization/39839] [4.3/4.4/4.5 regression] loop invariant motion causes stack spill
--- Comment #4 from bonzini at gnu dot org 2009-06-15 16:26 --- Someone can please check if this is still a problem in 4.5? -- bonzini at gnu dot org changed: What|Removed |Added CC||bonzini at gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39839
[Bug tree-optimization/39839] [4.3/4.4/4.5 regression] loop invariant motion causes stack spill
-- ramana at gcc dot gnu dot org changed: What|Removed |Added Status|UNCONFIRMED |NEW Ever Confirmed|0 |1 Last reconfirmed|-00-00 00:00:00 |2009-05-20 14:17:11 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39839
[Bug tree-optimization/39839] [4.3/4.4/4.5 regression] loop invariant motion causes stack spill
--- Comment #3 from vmakarov at redhat dot com 2009-04-22 20:37 --- Actually YARA did not have a rematerialization as IRA. Reload has a primitive rematerialization of constant values. Although about 5 years I did implemented a register pressure relief through rematerialization which is close to Simpson's thesis. It was reported on the 2nd GCC summit. I had a mixed feeling about this: wrong register pressure calculation (because we have not cover classes at that time), small improvement but a few additional percents to compilation time. Probably it is time to return to this and make it optional or default which will eat a chunk of your recent 5% compilation time improvement :) I'll try to include this in my plans. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39839
[Bug tree-optimization/39839] [4.3/4.4/4.5 regression] loop invariant motion causes stack spill
--- Comment #2 from rguenth at gcc dot gnu dot org 2009-04-22 13:39 --- Vlad, with YARA you had implemented rematerialization, right? How difficult is it to do the same with IRA for cases like this? -- rguenth at gcc dot gnu dot org changed: What|Removed |Added CC||vmakarov at redhat dot com Priority|P3 |P2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39839
[Bug tree-optimization/39839] [4.3/4.4/4.5 regression] loop invariant motion causes stack spill
--- Comment #1 from rguenth at gcc dot gnu dot org 2009-04-22 09:39 --- Implement re-materialization in reload. -- rguenth at gcc dot gnu dot org changed: What|Removed |Added Component|regression |tree-optimization Keywords||missed-optimization Target Milestone|--- |4.3.4 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39839
