| Message ID | orwmopn3ei.fsf@lxoliva.fsfla.org |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] add explicit ABI and align options to pr88233.c | expand |
On Apr 22, 2024, Alexandre Oliva <oliva@adacore.com> wrote: > for gcc/testsuite/ChangeLog > * gcc.target/powerpc/pr88233.c: Make some alignment strictness > and calling conventions assumptions explicit. Restore uniform > codegen expectations Ping? https://gcc.gnu.org/pipermail/gcc-patches/2024-April/649823.html
Hi, on 2024/4/22 17:38, Alexandre Oliva wrote: > Ping? > https://gcc.gnu.org/pipermail/gcc-patches/2021-March/566530.html > (modified version follows) Segher originated this test case, I was expecting he can chime in this. :) > > > We've observed failures of this test on powerpc configurations that > default to different calling conventions and alignment requirements. It seems that it was using the original "BE" and "LE" guards to shadow ABIs, could you share some more on how you found this failure? It seems that your test environment with -mstrict-align turned on by default? And also having a ABI which passing small struct return value in register? BR, Kewen > Both settings are needed for the original expectations to be met. > > The test was later modified to have different expectations for big and > little endian code generation. This patch restores the original > codegen expectations, that, with the explicit options, don't vary any > more. > > Regstrapped on x86_64-linux-gnu and ppc64el-linux-gnu. Also tested with > gcc-13 on ppc64-vx7r2 and ppc-vx7r2. Ok to install? > > > for gcc/testsuite/ChangeLog > > * gcc.target/powerpc/pr88233.c: Make some alignment strictness > and calling conventions assumptions explicit. Restore uniform > codegen expectations > --- > gcc/testsuite/gcc.target/powerpc/pr88233.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/gcc/testsuite/gcc.target/powerpc/pr88233.c b/gcc/testsuite/gcc.target/powerpc/pr88233.c > index 27c73717a3f79..46a3ebfa28775 100644 > --- a/gcc/testsuite/gcc.target/powerpc/pr88233.c > +++ b/gcc/testsuite/gcc.target/powerpc/pr88233.c > @@ -1,5 +1,5 @@ > /* { dg-require-effective-target lp64 } */ > -/* { dg-options "-O2 -mdejagnu-cpu=power8" } */ > +/* { dg-options "-O2 -mdejagnu-cpu=power8 -mno-strict-align -fpcc-struct-return" } */ > > typedef struct { double a[2]; } A; > A > @@ -9,6 +9,5 @@ foo (const A *a) > } > > /* { dg-final { scan-assembler-not {\mmtvsr} } } */ > -/* { dg-final { scan-assembler-times {\mlxvd2x\M} 1 { target { be } } } } */ > -/* { dg-final { scan-assembler-times {\mstxvd2x\M} 1 { target { be } } } } */ > -/* { dg-final { scan-assembler-times {\mlfd\M} 2 { target { le } } } } */ > +/* { dg-final { scan-assembler-times {\mlxvd2x\M} 1 } } */ > +/* { dg-final { scan-assembler-times {\mstxvd2x\M} 1 } } */ > >
On May 26, 2024, "Kewen.Lin" <linkw@linux.ibm.com> wrote: > Hi, > on 2024/4/22 17:38, Alexandre Oliva wrote: >> Ping? >> https://gcc.gnu.org/pipermail/gcc-patches/2021-March/566530.html >> (modified version follows) > Segher originated this test case, I was expecting he can chime in this. :) Me too ;-) >> We've observed failures of this test on powerpc configurations that >> default to different calling conventions and alignment requirements. > It seems that it was using the original "BE" and "LE" guards to shadow > ABIs, could you share some more on how you found this failure? It seems > that your test environment with -mstrict-align turned on by default? And > also having a ABI which passing small struct return value in register? Exactly, AdaCore's ppc64-vx7r2 are configured so as to enable -mstrict-align and -freg-struct-return by default. But since these settings may change depending on the target variant, I figured it would be useful to record what the assumptions are that the test makes. That one of these settings changed depending on endianness and affected codegen was, to me, further evidence that this would be useful, so, with the explicit settings, I could restore the original test's expectations.
on 2024/5/29 14:32, Alexandre Oliva wrote: > On May 26, 2024, "Kewen.Lin" <linkw@linux.ibm.com> wrote: > >> Hi, >> on 2024/4/22 17:38, Alexandre Oliva wrote: >>> Ping? >>> https://gcc.gnu.org/pipermail/gcc-patches/2021-March/566530.html >>> (modified version follows) > >> Segher originated this test case, I was expecting he can chime in this. :) > > Me too ;-) > >>> We've observed failures of this test on powerpc configurations that >>> default to different calling conventions and alignment requirements. > >> It seems that it was using the original "BE" and "LE" guards to shadow >> ABIs, could you share some more on how you found this failure? It seems >> that your test environment with -mstrict-align turned on by default? And >> also having a ABI which passing small struct return value in register? > > Exactly, AdaCore's ppc64-vx7r2 are configured so as to enable > -mstrict-align and -freg-struct-return by default. OK, thanks for the information! > > But since these settings may change depending on the target variant, I > figured it would be useful to record what the assumptions are that the > test makes. That one of these settings changed depending on endianness > and affected codegen was, to me, further evidence that this would be > useful, so, with the explicit settings, I could restore the original > test's expectations. Got it, but it also means we can probably test it without the default ABI on the test env, someone may argue this testing is of less value. By visiting the original PR, maybe we can drop the scanning on the load isns and just keep the scanning-not on mtvsr, it becomes not sensitive for the alignment and struct result passing way. Looking forward to Segher's opinion on this patch. :) BR, Kewen
diff --git a/gcc/testsuite/gcc.target/powerpc/pr88233.c b/gcc/testsuite/gcc.target/powerpc/pr88233.c index 27c73717a3f79..46a3ebfa28775 100644 --- a/gcc/testsuite/gcc.target/powerpc/pr88233.c +++ b/gcc/testsuite/gcc.target/powerpc/pr88233.c @@ -1,5 +1,5 @@ /* { dg-require-effective-target lp64 } */ -/* { dg-options "-O2 -mdejagnu-cpu=power8" } */ +/* { dg-options "-O2 -mdejagnu-cpu=power8 -mno-strict-align -fpcc-struct-return" } */ typedef struct { double a[2]; } A; A @@ -9,6 +9,5 @@ foo (const A *a) } /* { dg-final { scan-assembler-not {\mmtvsr} } } */ -/* { dg-final { scan-assembler-times {\mlxvd2x\M} 1 { target { be } } } } */ -/* { dg-final { scan-assembler-times {\mstxvd2x\M} 1 { target { be } } } } */ -/* { dg-final { scan-assembler-times {\mlfd\M} 2 { target { le } } } } */ +/* { dg-final { scan-assembler-times {\mlxvd2x\M} 1 } } */ +/* { dg-final { scan-assembler-times {\mstxvd2x\M} 1 } } */