on 2024/5/29 14:32, Alexandre Oliva wrote: > On May 26, 2024, "Kewen.Lin" <li...@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
