* [Bug target/94740] ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1
2020-04-24 1:31 [Bug target/94740] New: ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1 acsawdey at gcc dot gnu.org
@ 2020-04-24 2:37 ` acsawdey at gcc dot gnu.org
2020-04-24 16:08 ` bergner at gcc dot gnu.org
` (9 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: acsawdey at gcc dot gnu.org @ 2020-04-24 2:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94740
--- Comment #1 from acsawdey at gcc dot gnu.org ---
Reduced test case:
struct __attribute__((scalar_storage_order("big-endian"))) {
int a;
int b[];
} c;
int d;
int e() { d = c.b[0]; }
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug target/94740] ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1
2020-04-24 1:31 [Bug target/94740] New: ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1 acsawdey at gcc dot gnu.org
2020-04-24 2:37 ` [Bug target/94740] " acsawdey at gcc dot gnu.org
@ 2020-04-24 16:08 ` bergner at gcc dot gnu.org
2020-04-24 17:11 ` bergner at gcc dot gnu.org
` (8 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: bergner at gcc dot gnu.org @ 2020-04-24 16:08 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94740
Peter Bergner <bergner at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
Last reconfirmed| |2020-04-24
--- Comment #2 from Peter Bergner <bergner at gcc dot gnu.org> ---
Confirmed. I'll have a quick look.
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug target/94740] ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1
2020-04-24 1:31 [Bug target/94740] New: ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1 acsawdey at gcc dot gnu.org
2020-04-24 2:37 ` [Bug target/94740] " acsawdey at gcc dot gnu.org
2020-04-24 16:08 ` bergner at gcc dot gnu.org
@ 2020-04-24 17:11 ` bergner at gcc dot gnu.org
2020-04-24 17:14 ` bergner at gcc dot gnu.org
` (7 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: bergner at gcc dot gnu.org @ 2020-04-24 17:11 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94740
--- Comment #3 from Peter Bergner <bergner at gcc dot gnu.org> ---
Here's a simpler test case that fails the same way:
int array[8];
int
foo (void)
{
return __builtin_bswap32 (array[1]);
}
So before CSE, we have:
(insn 5 2 6 2 (set (reg/f:DI 121)
(symbol_ref:DI ("*.LANCHOR0") [flags 0x182]))
{*pcrel_local_addr})
(insn 6 5 7 2 (set (reg:DI 123)
(const_int 4 [0x4])) {*movdi_internal64})
(insn 7 6 8 2 (set (reg:SI 122)
(bswap:SI (mem/c:SI (plus:DI (reg/f:DI 121)
(reg:DI 123)))))
{bswapsi2_load}
(expr_list:REG_EQUAL (bswap:SI (mem/c:SI (plus:DI (reg/f:DI 121)
(const_int 4 [0x4]))))))
...
After CSE, we then have all the way up to LRA:
(insn 7 9 14 2 (set (reg:SI 122)
(bswap:SI (mem/c:SI (plus:DI (symbol_ref:DI ("*.LANCHOR0")
[flags 0x182])
(const_int 4))))) {bswapsi2_load})
...
LRA then calls decompse_address with the above address, which causes us to go
sideways. Not sure why yet. Maybe our bswap2_load pattern needs help?
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug target/94740] ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1
2020-04-24 1:31 [Bug target/94740] New: ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1 acsawdey at gcc dot gnu.org
` (2 preceding siblings ...)
2020-04-24 17:11 ` bergner at gcc dot gnu.org
@ 2020-04-24 17:14 ` bergner at gcc dot gnu.org
2020-04-27 18:33 ` [Bug rtl-optimization/94740] " bergner at gcc dot gnu.org
` (6 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: bergner at gcc dot gnu.org @ 2020-04-24 17:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94740
--- Comment #4 from Peter Bergner <bergner at gcc dot gnu.org> ---
Removing the bswap and recompiling, the non-bswap load pattern has no problem
accepting an address like that, so this looks like a target issue with that
pattern.
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug rtl-optimization/94740] ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1
2020-04-24 1:31 [Bug target/94740] New: ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1 acsawdey at gcc dot gnu.org
` (3 preceding siblings ...)
2020-04-24 17:14 ` bergner at gcc dot gnu.org
@ 2020-04-27 18:33 ` bergner at gcc dot gnu.org
2020-04-28 19:03 ` segher at gcc dot gnu.org
` (5 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: bergner at gcc dot gnu.org @ 2020-04-27 18:33 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94740
Peter Bergner <bergner at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |segher at gcc dot gnu.org
Component|target |rtl-optimization
--- Comment #5 from Peter Bergner <bergner at gcc dot gnu.org> ---
Looking into this more, it seems the problem is that CSE creates a constant
address and does not wrap it with a (const: ...). If the constant address does
have a (const: ) wrapper, then decompose_address handles this just fine. I can
modify the test case such that combine can combine our bswap load with a
following insn and combine will call simplify_binary_operation on the address
and it will create the (const: ) for us. CSE should probably do the same when
it creates a constant address.
The following patch fixes the ICE for me. I'll run it through bootstrap and
regtesting.
diff --git a/gcc/cse.c b/gcc/cse.c
index 5aaba8d80e0..870e2a21dbd 100644
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -6328,6 +6328,14 @@ cse_process_notes (rtx x, rtx object, bool *changed)
rtx new_rtx = cse_process_notes_1 (x, object, changed);
if (new_rtx != x)
*changed = true;
+ if (*changed && object != NULL_RTX && MEM_P (object))
+ {
+ /* Call simplify_rtx on the updated address in case it is now
+ a constant and needs to be wrapped with a (const: ...). */
+ rtx simplified_rtx = simplify_rtx (new_rtx);
+ if (simplified_rtx)
+ new_rtx = simplified_rtx;
+ }
return new_rtx;
}
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug rtl-optimization/94740] ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1
2020-04-24 1:31 [Bug target/94740] New: ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1 acsawdey at gcc dot gnu.org
` (4 preceding siblings ...)
2020-04-27 18:33 ` [Bug rtl-optimization/94740] " bergner at gcc dot gnu.org
@ 2020-04-28 19:03 ` segher at gcc dot gnu.org
2020-04-29 21:33 ` bergner at gcc dot gnu.org
` (4 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: segher at gcc dot gnu.org @ 2020-04-28 19:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94740
--- Comment #6 from Segher Boessenkool <segher at gcc dot gnu.org> ---
It is of course good to wrap things with CONST whenever possible, but it
isn't documented anywhere (afaics) that this would be required, so this
is a workaround, not a fix?
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug rtl-optimization/94740] ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1
2020-04-24 1:31 [Bug target/94740] New: ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1 acsawdey at gcc dot gnu.org
` (5 preceding siblings ...)
2020-04-28 19:03 ` segher at gcc dot gnu.org
@ 2020-04-29 21:33 ` bergner at gcc dot gnu.org
2020-04-30 19:01 ` cvs-commit at gcc dot gnu.org
` (3 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: bergner at gcc dot gnu.org @ 2020-04-29 21:33 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94740
Peter Bergner <bergner at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
URL| |https://gcc.gnu.org/piperma
| |il/gcc-patches/2020-April/5
| |44894.html
--- Comment #7 from Peter Bergner <bergner at gcc dot gnu.org> ---
Richard has a much better patch which we're both testing.
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug rtl-optimization/94740] ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1
2020-04-24 1:31 [Bug target/94740] New: ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1 acsawdey at gcc dot gnu.org
` (6 preceding siblings ...)
2020-04-29 21:33 ` bergner at gcc dot gnu.org
@ 2020-04-30 19:01 ` cvs-commit at gcc dot gnu.org
2020-04-30 19:33 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2020-04-30 19:01 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94740
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Sandiford <rsandifo@gcc.gnu.org>:
https://gcc.gnu.org/g:66ec22b0d3feb96049283abe5c6c9a05ecef8b86
commit r11-4-g66ec22b0d3feb96049283abe5c6c9a05ecef8b86
Author: Richard Sandiford <richard.sandiford@arm.com>
Date: Thu Apr 30 20:00:52 2020 +0100
cse: Use simplify_replace_fn_rtx to process notes [PR94740]
cse_process_notes did a very simple substitution, which in the wrong
circumstances could create non-canonical RTL and invalid MEMs.
Various sticking plasters have been applied to cse_process_notes_1
to handle cases like ZERO_EXTEND, SIGN_EXTEND and UNSIGNED_FLOAT,
but I think this PR is a plaster too far.
The code is trying hard to avoid creating unnecessary rtl, which of
course is a good thing. If we continue to do that, then we can end
up changing subexpressions while keeping the containing rtx.
This in turn means that validate_change will be a no-op on the
containing rtx, even if its contents have changed. So in these
cases we have to apply validate_change to the individual subexpressions.
On the other hand, if we always apply validate_change to the
individual subexpressions, we'll end up calling validate_change
on something before it has been simplified and canonicalised.
And that's one of the situations we're trying to avoid.
There might be a middle ground in which we queue the validate_changes
as part of a group, and so can cancel the pending validate_changes
for subexpressions if there's a change in the outer expression.
But that seems even more ad-hoc than the current code.
It would also be quite an invasive change.
I think the best thing is just to hook into the existing
simplify_replace_fn_rtx function, keeping the REG and MEM handling
from cse_process_notes_1 essentially unchanged. It can generate
more redundant rtl when a simplification takes place, but it has
the advantage of being relative well-used code (both directly
and via simplify_replace_rtx).
2020-04-30 Richard Sandiford <richard.sandiford@arm.com>
gcc/
PR rtl-optimization/94740
* cse.c (cse_process_notes_1): Replace with...
(cse_process_note_1): ...this new function, acting as a
simplify_replace_fn_rtx callback to process_note. Handle only
REGs and MEMs directly. Validate the MEM if cse_process_note
changes its address.
(cse_process_notes): Replace with...
(cse_process_note): ...this new function.
(cse_extended_basic_block): Update accordingly, iterating over
the register notes and passing individual notes to
cse_process_note.
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug rtl-optimization/94740] ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1
2020-04-24 1:31 [Bug target/94740] New: ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1 acsawdey at gcc dot gnu.org
` (7 preceding siblings ...)
2020-04-30 19:01 ` cvs-commit at gcc dot gnu.org
@ 2020-04-30 19:33 ` cvs-commit at gcc dot gnu.org
2020-04-30 23:22 ` cvs-commit at gcc dot gnu.org
2020-06-12 21:20 ` bergner at gcc dot gnu.org
10 siblings, 0 replies; 12+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2020-04-30 19:33 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94740
--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Richard Sandiford
<rsandifo@gcc.gnu.org>:
https://gcc.gnu.org/g:591d857164c37cd0bb96da2a293148e01f280e0f
commit r10-8080-g591d857164c37cd0bb96da2a293148e01f280e0f
Author: Richard Sandiford <richard.sandiford@arm.com>
Date: Thu Apr 30 20:32:49 2020 +0100
cse: Use simplify_replace_fn_rtx to process notes [PR94740]
cse_process_notes did a very simple substitution, which in the wrong
circumstances could create non-canonical RTL and invalid MEMs.
Various sticking plasters have been applied to cse_process_notes_1
to handle cases like ZERO_EXTEND, SIGN_EXTEND and UNSIGNED_FLOAT,
but I think this PR is a plaster too far.
The code is trying hard to avoid creating unnecessary rtl, which of
course is a good thing. If we continue to do that, then we can end
up changing subexpressions while keeping the containing rtx.
This in turn means that validate_change will be a no-op on the
containing rtx, even if its contents have changed. So in these
cases we have to apply validate_change to the individual subexpressions.
On the other hand, if we always apply validate_change to the
individual subexpressions, we'll end up calling validate_change
on something before it has been simplified and canonicalised.
And that's one of the situations we're trying to avoid.
There might be a middle ground in which we queue the validate_changes
as part of a group, and so can cancel the pending validate_changes
for subexpressions if there's a change in the outer expression.
But that seems even more ad-hoc than the current code.
It would also be quite an invasive change.
I think the best thing is just to hook into the existing
simplify_replace_fn_rtx function, keeping the REG and MEM handling
from cse_process_notes_1 essentially unchanged. It can generate
more redundant rtl when a simplification takes place, but it has
the advantage of being relative well-used code (both directly
and via simplify_replace_rtx).
2020-04-30 Richard Sandiford <richard.sandiford@arm.com>
gcc/
PR rtl-optimization/94740
* cse.c (cse_process_notes_1): Replace with...
(cse_process_note_1): ...this new function, acting as a
simplify_replace_fn_rtx callback to process_note. Handle only
REGs and MEMs directly. Validate the MEM if cse_process_note
changes its address.
(cse_process_notes): Replace with...
(cse_process_note): ...this new function.
(cse_extended_basic_block): Update accordingly, iterating over
the register notes and passing individual notes to
cse_process_note.
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug rtl-optimization/94740] ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1
2020-04-24 1:31 [Bug target/94740] New: ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1 acsawdey at gcc dot gnu.org
` (8 preceding siblings ...)
2020-04-30 19:33 ` cvs-commit at gcc dot gnu.org
@ 2020-04-30 23:22 ` cvs-commit at gcc dot gnu.org
2020-06-12 21:20 ` bergner at gcc dot gnu.org
10 siblings, 0 replies; 12+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2020-04-30 23:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94740
--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Peter Bergner <bergner@gcc.gnu.org>:
https://gcc.gnu.org/g:ff1e6276dd71fde59fde679557b5db1efca9f19c
commit r11-6-gff1e6276dd71fde59fde679557b5db1efca9f19c
Author: Peter Bergner <bergner@linux.ibm.com>
Date: Thu Apr 30 18:21:30 2020 -0500
cse: Add test case. [PR94740]
PR rtl-optimization/94740
* gcc.target/powerpc/pr94740.c: New test.
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug rtl-optimization/94740] ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1
2020-04-24 1:31 [Bug target/94740] New: ICE on testsuite/gcc.dg/sso/t5.c with -mcpu=future -mpcrel -O1 acsawdey at gcc dot gnu.org
` (9 preceding siblings ...)
2020-04-30 23:22 ` cvs-commit at gcc dot gnu.org
@ 2020-06-12 21:20 ` bergner at gcc dot gnu.org
10 siblings, 0 replies; 12+ messages in thread
From: bergner at gcc dot gnu.org @ 2020-06-12 21:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94740
Peter Bergner <bergner at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|NEW |RESOLVED
--- Comment #11 from Peter Bergner <bergner at gcc dot gnu.org> ---
Richard committed his patch, so this is fixed now.
^ permalink raw reply [flat|nested] 12+ messages in thread