Re: [PATCH v4] LoongArch: Fixed a compilation failure with '%c' in inline assembly [PR107731].

[Lulu Cheng <chenglulu@loongson.cn>]

Hi, Richard:

  Could you please help me look at this document? Is there any problem 
with my modification?

Thanks!


在 2022/12/27 下午2:42, Lulu Cheng 写道:
> Co-authored-by: Yang Yujie <yangyujie@loongson.cn>
>
> gcc/ChangeLog:
>
> 	* config/loongarch/loongarch.cc (loongarch_classify_address):
> 	Add precessint for CONST_INT.
> 	(loongarch_print_operand_reloc): Operand modifier 'c' is supported.
> 	(loongarch_print_operand): Increase the processing of '%c'.
> 	* doc/extend.texi: Adds documents for LoongArch operand modifiers.
>
> gcc/testsuite/ChangeLog:
>
> 	* gcc.target/loongarch/tst-asm-const.c: Moved to...
> 	* gcc.target/loongarch/pr107731.c: ...here.
>
> ---
> V2 -> v3:
> 1. Correct a clerical error.
> 2. Adding document for loongarch operand modifiers.
>
> v3 -> v4:
> Copy the description of "%c" "%n" "%a" "%l" from gccint.pdf to gcc.pdf.
>
>
> ---
>   gcc/config/loongarch/loongarch.cc             | 14 ++++++++
>   gcc/doc/extend.texi                           | 33 +++++++++++++++++++
>   .../loongarch/{tst-asm-const.c => pr107731.c} |  6 ++--
>   3 files changed, 50 insertions(+), 3 deletions(-)
>   rename gcc/testsuite/gcc.target/loongarch/{tst-asm-const.c => pr107731.c} (78%)
>
> diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
> index c6b03fcf2f9..cdf190b985e 100644
> --- a/gcc/config/loongarch/loongarch.cc
> +++ b/gcc/config/loongarch/loongarch.cc
> @@ -2075,6 +2075,11 @@ loongarch_classify_address (struct loongarch_address_info *info, rtx x,
>         return (loongarch_valid_base_register_p (info->reg, mode, strict_p)
>   	      && loongarch_valid_lo_sum_p (info->symbol_type, mode,
>   					   info->offset));
> +    case CONST_INT:
> +      /* Small-integer addresses don't occur very often, but they
> +	 are legitimate if $r0 is a valid base register.  */
> +      info->type = ADDRESS_CONST_INT;
> +      return IMM12_OPERAND (INTVAL (x));
>   
>       default:
>         return false;
> @@ -4933,6 +4938,7 @@ loongarch_print_operand_reloc (FILE *file, rtx op, bool hi64_part,
>   
>      'A'	Print a _DB suffix if the memory model requires a release.
>      'b'	Print the address of a memory operand, without offset.
> +   'c'  Print an integer.
>      'C'	Print the integer branch condition for comparison OP.
>      'd'	Print CONST_INT OP in decimal.
>      'F'	Print the FPU branch condition for comparison OP.
> @@ -4979,6 +4985,14 @@ loongarch_print_operand (FILE *file, rtx op, int letter)
>          fputs ("_db", file);
>         break;
>   
> +    case 'c':
> +      if (CONST_INT_P (op))
> +	fprintf (file, HOST_WIDE_INT_PRINT_DEC, INTVAL (op));
> +      else
> +	output_operand_lossage ("unsupported operand for code '%c'", letter);
> +
> +      break;
> +
>       case 'C':
>         loongarch_print_int_branch_condition (file, code, letter);
>         break;
> diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
> index adba057c190..1bb960266ed 100644
> --- a/gcc/doc/extend.texi
> +++ b/gcc/doc/extend.texi
> @@ -10234,6 +10234,24 @@ generates multiple assembler instructions.
>   Outputs @samp{@{}, @samp{|}, and @samp{@}} characters (respectively)
>   into the assembler code.  When unescaped, these characters have special
>   meaning to indicate multiple assembler dialects, as described below.
> +
> +@item %c@var{digit}
> +It can be used to substitute an operand that is a constant value without
> +the syntax that normally indicates an immediate operand.
> +
> +@item %n@var{digit}
> +It's like @samp{%c@var{digit}} except that the value of the constant is
> +negated before printing.
> +
> +@item %a@var{digit}
> +It Can be used to substitute an operand as if it were a memory reference,
> +with the actual operand treated as the address.  This may be useful when
> +outputting a ``load address'' instruction, because often the assembler
> +syntax for such an instruction requires you to write the operand as if it
> +were a memory reference.
> +
> +@item %l@var{digit}
> +It's used to substitute a @code{label_ref} into a jump instruction.
>   @end table
>   
>   @subsubheading Multiple assembler dialects in @code{asm} templates
> @@ -11374,6 +11392,21 @@ constant.  Used to select the specified bit position.
>   @item @code{x} @tab Equivialent to @code{X}, but only for pointers.
>   @end multitable
>   
> +@anchor{loongarchOperandmodifiers}
> +@subsubsection LoongArch Operand Modifiers
> +
> +The list below describes the supported modifiers and their effects for LoongArch.
> +
> +@multitable @columnfractions .10 .90
> +@headitem Modifier @tab Description
> +@item @code{d} @tab Same as @code{c}.
> +@item @code{i} @tab Print the character ''@code{i}'' if the operand is not a register.
> +@item @code{m} @tab Same as @code{c}, but the printed value is @code{operand - 1}.
> +@item @code{X} @tab Print a constant integer operand in hexadecimal.
> +@item @code{z} @tab Print the operand in its unmodified form, followed by a comma.
> +@end multitable
> +
> +
>   @lowersections
>   @include md.texi
>   @raisesections
> diff --git a/gcc/testsuite/gcc.target/loongarch/tst-asm-const.c b/gcc/testsuite/gcc.target/loongarch/pr107731.c
> similarity index 78%
> rename from gcc/testsuite/gcc.target/loongarch/tst-asm-const.c
> rename to gcc/testsuite/gcc.target/loongarch/pr107731.c
> index 2e04b99e301..80d84c48c6e 100644
> --- a/gcc/testsuite/gcc.target/loongarch/tst-asm-const.c
> +++ b/gcc/testsuite/gcc.target/loongarch/pr107731.c
> @@ -1,13 +1,13 @@
> -/* Test asm const. */
>   /* { dg-do compile } */
>   /* { dg-final { scan-assembler-times "foo:.*\\.long 1061109567.*\\.long 52" 1 } } */
> +
>   int foo ()
>   {
>     __asm__ volatile (
>             "foo:"
>             "\n\t"
> -	  ".long %a0\n\t"
> -	  ".long %a1\n\t"
> +	  ".long %c0\n\t"
> +	  ".long %c1\n\t"
>   	  :
>   	  :"i"(0x3f3f3f3f), "i"(52)
>   	  :