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

Co-authored-by: Yang Yujie <yangyujie@loongson.cn>

	PR target/107731

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.
	And port the public operand modifiers information to this document.

gcc/testsuite/ChangeLog:

	* gcc.target/loongarch/tst-asm-const.c: Moved to...
	* gcc.target/loongarch/pr107731.c: ...here.

3 files changed, 64 insertions, 7 deletions

diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index 2443966..6927bdc 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 0e2abe5..4a89a3e 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -10402,8 +10402,10 @@ ensures that modifying @var{a} does not affect the address referenced by
 is undefined if @var{a} is modified before using @var{b}.
 
 @code{asm} supports operand modifiers on operands (for example @samp{%k2} 
-instead of simply @samp{%2}). Typically these qualifiers are hardware 
-dependent. The list of supported modifiers for x86 is found at 
+instead of simply @samp{%2}). @ref{GenericOperandmodifiers,
+Generic Operand modifiers} lists the modifiers that are available
+on all targets.  Other modifiers are hardware dependent.
+For example, the list of supported modifiers for x86 is found at
 @ref{x86Operandmodifiers,x86 Operand modifiers}.
 
 If the C code that follows the @code{asm} makes no use of any of the output 
@@ -10671,8 +10673,10 @@ optimizers may discard the @code{asm} statement as unneeded
 (see @ref{Volatile}).
 
 @code{asm} supports operand modifiers on operands (for example @samp{%k2} 
-instead of simply @samp{%2}). Typically these qualifiers are hardware 
-dependent. The list of supported modifiers for x86 is found at 
+instead of simply @samp{%2}). @ref{GenericOperandmodifiers,
+Generic Operand modifiers} lists the modifiers that are available
+on all targets.  Other modifiers are hardware dependent.
+For example, the list of supported modifiers for x86 is found at
 @ref{x86Operandmodifiers,x86 Operand modifiers}.
 
 In this example using the fictitious @code{combine} instruction, the 
@@ -11024,6 +11028,30 @@ lab:
 @}
 @end example
 
+@anchor{GenericOperandmodifiers}
+@subsubsection Generic Operand Modifiers
+@noindent
+The following table shows the modifiers supported by all targets and their effects:
+
+@multitable {Modifier} {Description} {Example}
+@headitem Modifier @tab Description @tab Example
+@item @code{c}
+@tab Require a constant operand and print the constant expression with no punctuation.
+@tab @code{%c0}
+@item @code{n}
+@tab Like @samp{%c} except that the value of the constant is negated before printing.
+@tab @code{%n0}
+@item @code{a}
+@tab Substitute 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.
+@tab @code{%a0}
+@item @code{l}
+@tab Print the label name with no punctuation.
+@tab @code{%l0}
+@end multitable
+
 @anchor{x86Operandmodifiers}
 @subsubsection x86 Operand Modifiers
 
@@ -11374,6 +11402,21 @@ 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
index 2e04b99..80d84c4 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)
 	  :