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* [Bug target/100000] New: arm: Missed optimisation storing V4DF vector
@ 2021-04-09 14:43 acoplan at gcc dot gnu.org
2021-04-10 20:16 ` [Bug target/100000] non-leaf epologue/prologue used if MVE v4sf is used for load/return pinskia at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: acoplan at gcc dot gnu.org @ 2021-04-09 14:43 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100000
Bug ID: 100000
Summary: arm: Missed optimisation storing V4DF vector
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: acoplan at gcc dot gnu.org
Target Milestone: ---
typedef float __attribute((vector_size(16))) v4sf;
v4sf f(v4sf *p)
{
return *p;
}
gives:
f:
vldrw.32 q0, [r0]
sub sp, sp, #32
add sp, sp, #32
bx lr
with -march=armv8.1-m.main+mve -mfloat-abi=hard -O2 but the sub/add is
redundant.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug target/100000] non-leaf epologue/prologue used if MVE v4sf is used for load/return
2021-04-09 14:43 [Bug target/100000] New: arm: Missed optimisation storing V4DF vector acoplan at gcc dot gnu.org
@ 2021-04-10 20:16 ` pinskia at gcc dot gnu.org
2021-12-09 1:32 ` pinskia at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-04-10 20:16 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100000
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
Summary|arm: Missed optimisation |non-leaf epologue/prologue
|storing MVE V4SF vector |used if MVE v4sf is used
| |for load/return
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug target/100000] non-leaf epologue/prologue used if MVE v4sf is used for load/return
2021-04-09 14:43 [Bug target/100000] New: arm: Missed optimisation storing V4DF vector acoplan at gcc dot gnu.org
2021-04-10 20:16 ` [Bug target/100000] non-leaf epologue/prologue used if MVE v4sf is used for load/return pinskia at gcc dot gnu.org
@ 2021-12-09 1:32 ` pinskia at gcc dot gnu.org
2023-01-25 17:45 ` rearnsha at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-09 1:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100000
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
Known to fail| |10.2.1
Last reconfirmed| |2021-12-09
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug target/100000] non-leaf epologue/prologue used if MVE v4sf is used for load/return
2021-04-09 14:43 [Bug target/100000] New: arm: Missed optimisation storing V4DF vector acoplan at gcc dot gnu.org
2021-04-10 20:16 ` [Bug target/100000] non-leaf epologue/prologue used if MVE v4sf is used for load/return pinskia at gcc dot gnu.org
2021-12-09 1:32 ` pinskia at gcc dot gnu.org
@ 2023-01-25 17:45 ` rearnsha at gcc dot gnu.org
2023-01-25 17:50 ` rearnsha at gcc dot gnu.org
2023-03-09 15:27 ` stammark at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: rearnsha at gcc dot gnu.org @ 2023-01-25 17:45 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100000
--- Comment #2 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
If the testcase is built with -march=armv8.1-m.main+mve.fp then the useless
stack adjustments go away. I think that's because V4SFmode is not a supported
vector mode for integer MVE - see arm_vector_mode_supported_p() in arm.cc.
When it isn't a builtin type we end up with a BLKmode object that the compiler
creates a stack-slot for, even though no RTL is ever generated to use the slot
in this case.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/100000] non-leaf epologue/prologue used if MVE v4sf is used for load/return
2021-04-09 14:43 [Bug target/100000] New: arm: Missed optimisation storing V4DF vector acoplan at gcc dot gnu.org
` (2 preceding siblings ...)
2023-01-25 17:45 ` rearnsha at gcc dot gnu.org
@ 2023-01-25 17:50 ` rearnsha at gcc dot gnu.org
2023-03-09 15:27 ` stammark at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: rearnsha at gcc dot gnu.org @ 2023-01-25 17:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100000
--- Comment #3 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
Given that the hard-float ABI essentially requires V4SF as a type, it might be
better to consider this mode supported unconditionally in this case, and
although that might make the compiler try some pointless vectorizations it
would generate better code for cases like this.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug target/100000] non-leaf epologue/prologue used if MVE v4sf is used for load/return
2021-04-09 14:43 [Bug target/100000] New: arm: Missed optimisation storing V4DF vector acoplan at gcc dot gnu.org
` (3 preceding siblings ...)
2023-01-25 17:50 ` rearnsha at gcc dot gnu.org
@ 2023-03-09 15:27 ` stammark at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: stammark at gcc dot gnu.org @ 2023-03-09 15:27 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100000
Stam Markianos-Wright <stammark at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |stammark at gcc dot gnu.org
Status|NEW |ASSIGNED
--- Comment #4 from Stam Markianos-Wright <stammark at gcc dot gnu.org> ---
I tried out Richard's suggestion in arm_vector_mode_supported_p (allowing V8HF,
V4SF and V2DF unconditionally) and it seems to have worked! After a testsuite
run I found a few ICEs due to a number of patterns that needed enabling:
@mve_vpselq_<supf><mode> which was only enabled for mve.fp
And then all the patterns that were conditional on:
- "((TARGET_HAVE_MVE && VALID_MVE_SI_MODE (<MODE>mode))
- || (TARGET_HAVE_MVE_FLOAT && VALID_MVE_SF_MODE (<MODE>mode)))
mve_vec_extract<mode><V_elem_l>
*mve_vec_extract_sext_internal<mode>
*mve_vec_extract_zext_internal<mode>
mve_vec_set<mode>_internal
*movmisalign<mode>_mve_store
*movmisalign<mode>_mve_load
These weren't causing any ICEs but also made sense to enable:
mve_vst2q<mode>
mve_vld2q<mode>
mve_vld4q<mode>
No regressions after that, but I think I will hold off until GCC14 Stage 1 to
post this patch, just to be safe.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-03-09 15:27 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2021-04-09 14:43 [Bug target/100000] New: arm: Missed optimisation storing V4DF vector acoplan at gcc dot gnu.org
2021-04-10 20:16 ` [Bug target/100000] non-leaf epologue/prologue used if MVE v4sf is used for load/return pinskia at gcc dot gnu.org
2021-12-09 1:32 ` pinskia at gcc dot gnu.org
2023-01-25 17:45 ` rearnsha at gcc dot gnu.org
2023-01-25 17:50 ` rearnsha at gcc dot gnu.org
2023-03-09 15:27 ` stammark at gcc dot gnu.org
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