Re: [RS6000] Don't pass -many to the assembler

[Michael Matz <matz@suse.de>]

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"						\
> 
>