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Re: [RS6000] Don't pass -many to the assembler
- From: Michael Matz <matz at suse dot de>
- To: Alan Modra <amodra at gmail dot com>
- Cc: gcc-patches at gcc dot gnu dot org, Segher Boessenkool <segher at kernel dot crashing dot org>
- Date: Mon, 12 Nov 2018 14:39:06 +0000 (UTC)
- Subject: Re: [RS6000] Don't pass -many to the assembler
- References: <20181112114904.GH22752@bubble.grove.modra.org>
Hi,
On Mon, 12 Nov 2018, Alan Modra wrote:
> I'd like to remove -many from the options passed by default to the
> assembler, on the grounds that a gcc bug in instruction selection (eg.
> emitting a power9 insn for -mcpu=power8) is better found at assembly
> time than run time.
>
> This might annoy people for a while fixing user asm that we didn't
> diagnose previously, but I believe this is the right direction to go. Of
> course, -Wa,-many is available for anyone who just wants their dodgy old
> code to work.
Wouldn't this also break compiling code that contains power9 instructions
but guarded by runtime tests to only be executed on power9 machines? That
seems a valid usecase, and it'd be bad if the assembler fails to compile
such. (You can't use -mcpu=power9 as work around as the other
unguarded code is not supposed to be using power9 insns).
Ciao,
Michael.
>
> Bootstrapped etc. powerpc64le-linux. OK?
>
> * config/rs6000/rs6000.h (ASM_CPU_SPEC): Remove -many.
> * config/rs6000/aix61.h (ASM_CPU_SPEC): Likewise.
> * config/rs6000/aix71.h (ASM_CPU_SPEC): Likewise.
> * testsuite/gcc.target/powerpc/ppc32-abi-dfp-1.c: Don't use
> power mnemonics.
>
> diff --git a/gcc/config/rs6000/aix61.h b/gcc/config/rs6000/aix61.h
> index 353e5d6cfeb..a7a8246bfe3 100644
> --- a/gcc/config/rs6000/aix61.h
> +++ b/gcc/config/rs6000/aix61.h
> @@ -91,8 +91,7 @@ do { \
> %{mcpu=630: -m620} \
> %{mcpu=970: -m970} \
> %{mcpu=G5: -m970} \
> -%{mvsx: %{!mcpu*: -mpwr6}} \
> --many"
> +%{mvsx: %{!mcpu*: -mpwr6}}"
>
> #undef ASM_DEFAULT_SPEC
> #define ASM_DEFAULT_SPEC "-mpwr4"
> diff --git a/gcc/config/rs6000/aix71.h b/gcc/config/rs6000/aix71.h
> index 2398ed64baa..d2ca8dc275d 100644
> --- a/gcc/config/rs6000/aix71.h
> +++ b/gcc/config/rs6000/aix71.h
> @@ -89,8 +89,7 @@ do { \
> maltivec: -m970; \
> maix64|mpowerpc64: -mppc64; \
> : %(asm_default)}; \
> - :%eMissing -mcpu option in ASM_SPEC_CPU?\n} \
> --many"
> + :%eMissing -mcpu option in ASM_SPEC_CPU?\n}"
>
> #undef ASM_DEFAULT_SPEC
> #define ASM_DEFAULT_SPEC "-mpwr4"
> diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
> index d75137cf8f5..9d78173a680 100644
> --- a/gcc/config/rs6000/rs6000.h
> +++ b/gcc/config/rs6000/rs6000.h
> @@ -137,8 +137,7 @@
> mvsx: -mpower7; \
> mpowerpc64: -mppc64;: %(asm_default)}; \
> :%eMissing -mcpu option in ASM_SPEC_CPU?\n} \
> -%{mvsx: -mvsx -maltivec; maltivec: -maltivec} \
> --many"
> +%{mvsx: -mvsx -maltivec; maltivec: -maltivec}"
>
> #define CPP_DEFAULT_SPEC ""
>
> diff --git a/gcc/testsuite/gcc.target/powerpc/ppc32-abi-dfp-1.c b/gcc/testsuite/gcc.target/powerpc/ppc32-abi-dfp-1.c
> index 14908dba690..eea7f6ffc2e 100644
> --- a/gcc/testsuite/gcc.target/powerpc/ppc32-abi-dfp-1.c
> +++ b/gcc/testsuite/gcc.target/powerpc/ppc32-abi-dfp-1.c
> @@ -45,14 +45,14 @@ __asm__ ("\t.globl\t" #NAME "_asm\n\t" \
> #NAME "_asm:\n\t" \
> "lis 11,gparms@ha\n\t" \
> "la 11,gparms@l(11)\n\t" \
> - "st 3,0(11)\n\t" \
> - "st 4,4(11)\n\t" \
> - "st 5,8(11)\n\t" \
> - "st 6,12(11)\n\t" \
> - "st 7,16(11)\n\t" \
> - "st 8,20(11)\n\t" \
> - "st 9,24(11)\n\t" \
> - "st 10,28(11)\n\t" \
> + "stw 3,0(11)\n\t" \
> + "stw 4,4(11)\n\t" \
> + "stw 5,8(11)\n\t" \
> + "stw 6,12(11)\n\t" \
> + "stw 7,16(11)\n\t" \
> + "stw 8,20(11)\n\t" \
> + "stw 9,24(11)\n\t" \
> + "stw 10,28(11)\n\t" \
> "stfd 1,32(11)\n\t" \
> "stfd 2,40(11)\n\t" \
> "stfd 3,48(11)\n\t" \
>
>