Hi Peter,
on 2024/7/13 05:48, Peter Bergner wrote:
> René's patch seems to have stalled, so here is an updated version of the
> patch with the requested changes to his patch.
>
> I'll note I have added an additional code change, which is to also emit a
> ".machine altivec" if Altivec is enabled. The problem this fixes is for
> cpus like the G5, which is basically a power4 plus an Altivec unit, its
> ".machine power4" doesn't enable the assembler to recognize Altivec insns.
> That isn't a problem if you use gcc -mcpu=G5 to assemble the assembler file,
> since gcc passes -maltivec to the assembler. However, if you try to assemble
> the assembler file with as by hand, you'll get "unrecognized opcode" errors.
> I did not do the same for VSX, since all ".machine <cpu>" for cpus that
> support VSX already enable VSX insn recognition, so it's not needed.
Sounds great, thanks for improving it.
>
>
> rs6000: Fix .machine cpu selection w/ altivec [PR97367]
>
> There are various non-IBM CPUs with altivec, so we cannot use that
> flag to determine which .machine cpu to use, so ignore it.
> Emit an additional ".machine altivec" if Altivec is enabled so
> that the assembler doesn't require an explicit -maltivec option
> to assemble any Altivec instructions for those targets where
> the ".machine cpu" is insufficient to enable Altivec. For example,
> -mcpu=G5 emits a ".machine power4".
>
> This passed bootstrap and regtesting on powrpc64-linux (running the testsuite
> in both 32-bit and 64-bit modes) with no regressions.
>
> Ok for trunk and the release branches after some trunk burn-in time?
OK for all with/without the below minor nit tweaked.
>
> Peter
>
>
> 2024-07-12 René Rebe <r...@exactcode.de>
> Peter Bergner <berg...@linux.ibm.com>
>
> gcc/
> PR target/97367
> * config/rs6000/rs6000.c (rs6000_machine_from_flags): Do not consider
> OPTION_MASK_ALTIVEC.
> (emit_asm_machine): For Altivec compiles, emit a ".machine altivec".
>
> gcc/testsuite/
> PR target/97367
> * gcc.target/powerpc/pr97367.c: New test.
>
> Signed-of-by: René Rebe <r...@exactcode.de>
> ---
> gcc/config/rs6000/rs6000.cc | 5 ++++-
> gcc/testsuite/gcc.target/powerpc/pr97367.c | 13 +++++++++++++
> 2 files changed, 17 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/gcc.target/powerpc/pr97367.c
>
> diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
> index 2cbea6ea2d7..2cb8f35739b 100644
> --- a/gcc/config/rs6000/rs6000.cc
> +++ b/gcc/config/rs6000/rs6000.cc
> @@ -5888,7 +5888,8 @@ rs6000_machine_from_flags (void)
> HOST_WIDE_INT flags = rs6000_isa_flags;
>
> /* Disable the flags that should never influence the .machine selection.
> */
> - flags &= ~(OPTION_MASK_PPC_GFXOPT | OPTION_MASK_PPC_GPOPT |
> OPTION_MASK_ISEL);
> + flags &= ~(OPTION_MASK_PPC_GFXOPT | OPTION_MASK_PPC_GPOPT |
> OPTION_MASK_ISEL
> + | OPTION_MASK_ALTIVEC);
>
> if ((flags & (ISA_3_1_MASKS_SERVER & ~ISA_3_0_MASKS_SERVER)) != 0)
> return "power10";
> @@ -5913,6 +5914,8 @@ void
> emit_asm_machine (void)
> {
> fprintf (asm_out_file, "\t.machine %s\n", rs6000_machine);
> + if (TARGET_ALTIVEC)
> + fprintf (asm_out_file, "\t.machine altivec\n");
> }
> #endif
>
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr97367.c
> b/gcc/testsuite/gcc.target/powerpc/pr97367.c
> new file mode 100644
> index 00000000000..f9118dbcdec
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr97367.c
> @@ -0,0 +1,13 @@
> +/* PR target/97367 */
> +/* { dg-options "-mdejagnu-cpu=G5" } */
> +
> +/* Verify we emit a ".machine power4" and ".machine altivec" rather
> + than a ".machine power7". */
> +
> +int dummy (void)
> +{
> + return 0;
> +}
> +
> +/* { dg-final { scan-assembler {\.\mmachine power4\M} } } */
> +/* { dg-final { scan-assembler {\.\mmachine altivec\M} } } */
Nit: Both \m looks useless and can be removed.
BR,
Kewen
