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* [Bug middle-end/64448] New: New middle-end pattern breaks vector BIF folding on AArch64.
@ 2014-12-30 18:12 belagod at gcc dot gnu.org
2015-01-05 12:17 ` [Bug middle-end/64448] " mpolacek at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: belagod at gcc dot gnu.org @ 2014-12-30 18:12 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64448
Bug ID: 64448
Summary: New middle-end pattern breaks vector BIF folding on
AArch64.
Product: gcc
Version: 5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: belagod at gcc dot gnu.org
This new pattern
Author: mpolacek <mpolacek@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Wed Dec 17 11:48:33 2014 +0000
PR middle-end/63568
match.pd: Add (x & ~m) | (y & m) -> ((x ^ y) & m) ^ x pattern.
gcc.dg/pr63568.c: New test.
breaks BSL folding to a BIF on AArch64.
Causes this regression:
FAIL: gcc.target/aarch64/vbslq_u64_1.c scan-assembler-times bif\\tv 1
The code now generated is:
vbslq_dummy_u32:
eor v0.16b, v1.16b, v0.16b
and v0.16b, v0.16b, v2.16b
eor v0.16b, v1.16b, v0.16b
ret
.size vbslq_dummy_u32, .-vbslq_dummy_
instead of:
vbslq_dummy_u32:
bif v0.16b, v1.16b, v2.16b
ret
.size vbslq_dummy_u32, .-vbslq_dummy_u32
Optimized tree when folding happens:
vbslq_dummy_u32 (uint32x4_t a, uint32x4_t b, uint32x4_t mask)
{
__Uint32x4_t _3;
__Uint32x4_t _4;
__Uint32x4_t _6;
uint32x4_t _7;
<bb 2>:
_3 = mask_1(D) & a_2(D);
_4 = ~mask_1(D);
_6 = _4 & b_5(D);
_7 = _3 | _6;
return _7;
}
Optimized tree where folding does not happen:
vbslq_dummy_u32 (uint32x4_t a, uint32x4_t b, uint32x4_t mask)
{
__Uint32x4_t _3;
__Uint32x4_t _5;
uint32x4_t _6;
<bb 2>:
_3 = b_1(D) ^ a_2(D);
_5 = _3 & mask_4(D);
_6 = b_1(D) ^ _5;
return _6;
}
This will probably need another idiom to be caught by the BSL -> BIF folder.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/64448] New middle-end pattern breaks vector BIF folding on AArch64.
2014-12-30 18:12 [Bug middle-end/64448] New: New middle-end pattern breaks vector BIF folding on AArch64 belagod at gcc dot gnu.org
@ 2015-01-05 12:17 ` mpolacek at gcc dot gnu.org
2015-01-09 10:07 ` [Bug target/64448] " ktkachov at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2015-01-05 12:17 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64448
--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Looks like something for combine?
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/64448] New middle-end pattern breaks vector BIF folding on AArch64.
2014-12-30 18:12 [Bug middle-end/64448] New: New middle-end pattern breaks vector BIF folding on AArch64 belagod at gcc dot gnu.org
2015-01-05 12:17 ` [Bug middle-end/64448] " mpolacek at gcc dot gnu.org
@ 2015-01-09 10:07 ` ktkachov at gcc dot gnu.org
2015-01-15 10:16 ` [Bug target/64448] [5.0 regression] " ramana at gcc dot gnu.org
2015-01-19 14:04 ` [Bug target/64448] [5 Regression] " ktkachov at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: ktkachov at gcc dot gnu.org @ 2015-01-09 10:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64448
ktkachov at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Target| |aarch64*
Status|UNCONFIRMED |ASSIGNED
Keywords| |missed-optimization
Last reconfirmed| |2015-01-09
Component|middle-end |target
CC| |ktkachov at gcc dot gnu.org
Ever confirmed|0 |1
Known to fail| |5.0
--- Comment #2 from ktkachov at gcc dot gnu.org ---
Yeah, a matter for the backend. I'll take it.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/64448] [5.0 regression] New middle-end pattern breaks vector BIF folding on AArch64.
2014-12-30 18:12 [Bug middle-end/64448] New: New middle-end pattern breaks vector BIF folding on AArch64 belagod at gcc dot gnu.org
2015-01-05 12:17 ` [Bug middle-end/64448] " mpolacek at gcc dot gnu.org
2015-01-09 10:07 ` [Bug target/64448] " ktkachov at gcc dot gnu.org
@ 2015-01-15 10:16 ` ramana at gcc dot gnu.org
2015-01-19 14:04 ` [Bug target/64448] [5 Regression] " ktkachov at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: ramana at gcc dot gnu.org @ 2015-01-15 10:16 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64448
Ramana Radhakrishnan <ramana at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |ktkachov at gcc dot gnu.org
Target Milestone|--- |5.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/64448] [5 Regression] New middle-end pattern breaks vector BIF folding on AArch64.
2014-12-30 18:12 [Bug middle-end/64448] New: New middle-end pattern breaks vector BIF folding on AArch64 belagod at gcc dot gnu.org
` (2 preceding siblings ...)
2015-01-15 10:16 ` [Bug target/64448] [5.0 regression] " ramana at gcc dot gnu.org
@ 2015-01-19 14:04 ` ktkachov at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: ktkachov at gcc dot gnu.org @ 2015-01-19 14:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64448
--- Comment #3 from ktkachov at gcc dot gnu.org ---
Author: ktkachov
Date: Mon Jan 19 14:03:23 2015
New Revision: 219843
URL: https://gcc.gnu.org/viewcvs?rev=219843&root=gcc&view=rev
Log:
[AArch64] PR 64448: Combine ((x ^ y) & m) ^ x into bsl/bif instruction
PR target/64448
* config/aarch64/aarch64-simd.md (aarch64_simd_bsl<mode>_internal):
Match xor-and-xor RTL pattern.
Modified:
trunk/gcc/ChangeLog
trunk/gcc/config/aarch64/aarch64-simd.md
^ permalink raw reply [flat|nested] 5+ messages in thread
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2014-12-30 18:12 [Bug middle-end/64448] New: New middle-end pattern breaks vector BIF folding on AArch64 belagod at gcc dot gnu.org
2015-01-05 12:17 ` [Bug middle-end/64448] " mpolacek at gcc dot gnu.org
2015-01-09 10:07 ` [Bug target/64448] " ktkachov at gcc dot gnu.org
2015-01-15 10:16 ` [Bug target/64448] [5.0 regression] " ramana at gcc dot gnu.org
2015-01-19 14:04 ` [Bug target/64448] [5 Regression] " ktkachov at gcc dot gnu.org
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