[ was: Re: [committed][testsuite] Require non_strict_align in
pr94600-{1,3}.c ]
On 9/30/20 4:53 AM, Hans-Peter Nilsson wrote:
> On Thu, 24 Sep 2020, Tom de Vries wrote:
>
>> Hi,
>>
>> With the nvptx target, we run into:
>> ...
>> FAIL: gcc.dg/pr94600-1.c scan-rtl-dump-times final "\\(mem/v" 6
>> FAIL: gcc.dg/pr94600-1.c scan-rtl-dump-times final "\\(set \\(mem/v" 6
>> FAIL: gcc.dg/pr94600-3.c scan-rtl-dump-times final "\\(mem/v" 1
>> FAIL: gcc.dg/pr94600-3.c scan-rtl-dump-times final "\\(set \\(mem/v" 1
>> ...
>> The scans attempt to check for volatile stores, but on nvptx we have memcpy
>> instead.
>>
>> This is due to nvptx being a STRICT_ALIGNMENT target, which has the effect
>> that the TYPE_MODE for the store target is set to BKLmode in
>> compute_record_mode.
>>
>> Fix the FAILs by requiring effective target non_strict_align.
>
> No, that's wrong. There's more than that at play; it worked for
> the strict-alignment targets where it was tested at the time.
>
Hi,
thanks for letting me know.
> The test is a valuable canary for this kind of bug. You now
> disabled it for strict-alignment targets.
>
> Please revert and add your target specifier instead, if you
> don't feel like investigating further.
I've analyzed the compilation on strict-alignment target arm-eabi, and
broadened the effective target to (non_strict_align ||
pcc_bitfield_type_matters).
Thanks,
- Tom
[testsuite] Re-enable pr94600-{1,3}.c tests for arm
Before commit 7e437162001 "[testsuite] Require non_strict_align in
pr94600-{1,3}.c", some tests were failing for nvptx, because volatile stores
were expected, but memcpy's were found instead.
This was traced back to this bit in compute_record_mode:
...
/* If structure's known alignment is less than what the scalar
mode would need, and it matters, then stick with BLKmode. */
if (mode != BLKmode
&& STRICT_ALIGNMENT
&& ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
|| TYPE_ALIGN (type) >= GET_MODE_ALIGNMENT (mode)))
{
/* If this is the only reason this type is BLKmode, then
don't force containing types to be BLKmode. */
TYPE_NO_FORCE_BLK (type) = 1;
mode = BLKmode;
}
...
which got triggered for nvptx, but not for x86_64.
The commit disabled the tests for non_strict_align effective target, but
that had the effect for the arm target that those tests were disabled, even
though they were passing before.
Further investigation in compute_record_mode shows that the if-condition
evaluates to false for arm because, because TYPE_ALIGN (type) == 32, while
it's 8 for nvptx. This again can be explained by the
PCC_BITFIELD_TYPE_MATTERS setting, which is 1 for arm, but 0 for nvptx.
Re-enable the test for arm by using effective target
(non_strict_align || pcc_bitfield_type_matters).
Tested on arm-eabi and nvptx.
gcc/testsuite/ChangeLog:
2020-09-30 Tom de Vries <[email protected]>
* gcc.dg/pr94600-1.c: Use effective target
(non_strict_align || pcc_bitfield_type_matters).
* gcc.dg/pr94600-3.c: Same.
---
gcc/testsuite/gcc.dg/pr94600-1.c | 4 ++--
gcc/testsuite/gcc.dg/pr94600-3.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/gcc/testsuite/gcc.dg/pr94600-1.c b/gcc/testsuite/gcc.dg/pr94600-1.c
index 38f939a98cb..c9a7bb9007e 100644
--- a/gcc/testsuite/gcc.dg/pr94600-1.c
+++ b/gcc/testsuite/gcc.dg/pr94600-1.c
@@ -32,5 +32,5 @@ foo(void)
}
/* The only volatile accesses should be the obvious writes. */
-/* { dg-final { scan-rtl-dump-times {\(mem/v} 6 "final" { target { non_strict_align } } } } */
-/* { dg-final { scan-rtl-dump-times {\(set \(mem/v} 6 "final" { target { non_strict_align } } } } */
+/* { dg-final { scan-rtl-dump-times {\(mem/v} 6 "final" { target { non_strict_align || pcc_bitfield_type_matters } } } } */
+/* { dg-final { scan-rtl-dump-times {\(set \(mem/v} 6 "final" { target { non_strict_align || pcc_bitfield_type_matters } } } } */
diff --git a/gcc/testsuite/gcc.dg/pr94600-3.c b/gcc/testsuite/gcc.dg/pr94600-3.c
index e8776fbdb28..ff42c7db3c6 100644
--- a/gcc/testsuite/gcc.dg/pr94600-3.c
+++ b/gcc/testsuite/gcc.dg/pr94600-3.c
@@ -31,5 +31,5 @@ foo(void)
}
/* The loop isn't unrolled. */
-/* { dg-final { scan-rtl-dump-times {\(mem/v} 1 "final" { target { non_strict_align } } } } */
-/* { dg-final { scan-rtl-dump-times {\(set \(mem/v} 1 "final" { target { non_strict_align } } } } */
+/* { dg-final { scan-rtl-dump-times {\(mem/v} 1 "final" { target { non_strict_align || pcc_bitfield_type_matters } } } } */
+/* { dg-final { scan-rtl-dump-times {\(set \(mem/v} 1 "final" { target { non_strict_align || pcc_bitfield_type_matters } } } } */
