PR ice/13473

[Jan Hubicka <jh at suse dot cz>]

Hi,
the problem is that recog calls replacement of (reg X) by (subreg (reg X)).
This is sane because it first take care to change mode of (reg X).
validate_replace_rtx usually is able to deal with this, but in this case
it gets into recursive replacement because it sees already replaced RTL
throught sharing inside ASM_OPERANDS.

typedef unsigned short uint16_t;
typedef unsigned int uint32_t;

#define CF (1<<0)
#define PF (1<<2)
#define AF (1<<4)
#define ZF (1<<6)
#define SF (1<<7)
#define OF (1<<11)

#define EFLAGS_BITS (CF|PF|AF|ZF|SF|OF)

void test16(uint16_t x, uint32_t eflags)
{
        uint16_t bsr_result;
        uint32_t bsr_eflags;
        uint16_t bsf_result;
        uint32_t bsf_eflags;

        __asm volatile(""
                : "=&r" (bsr_result), "=&r" (bsr_eflags)
                : "r" (x), "i" (~EFLAGS_BITS), "r" (eflags));
        __asm volatile(""
                : "=&r" (bsf_result), "=&r" (bsf_eflags)
                : "r" (x), "i" (~EFLAGS_BITS), "r" (eflags));
        printf("%08x %04x bsrw %02x %08x bsfw %02x %08x\n",
                x, eflags, bsr_result, bsr_eflags, bsf_result, bsf_eflags);
}

	PR ice/13473
	* recog.c (validate_replace_rtx_1):  Take care for RTL sharing inside
	ASM input operands
Index: recog.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/recog.c,v
retrieving revision 1.190
diff -c -3 -p -r1.190 recog.c
*** recog.c	11 Dec 2003 00:20:46 -0000	1.190
--- recog.c	29 Dec 2003 11:20:13 -0000
*************** validate_replace_rtx_1 (rtx *loc, rtx fr
*** 476,491 ****
        return;
      }
  
!   /* Call ourself recursively to perform the replacements.  */
  
!   for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
      {
!       if (fmt[i] == 'e')
! 	validate_replace_rtx_1 (&XEXP (x, i), from, to, object);
!       else if (fmt[i] == 'E')
! 	for (j = XVECLEN (x, i) - 1; j >= 0; j--)
! 	  validate_replace_rtx_1 (&XVECEXP (x, i, j), from, to, object);
      }
  
    /* If we didn't substitute, there is nothing more to do.  */
    if (num_changes == prev_changes)
--- 476,513 ----
        return;
      }
  
!   /* Call ourself recursively to perform the replacements.
!      We must not replace inside already replaced expression, otherwise we
!      get infinite recursion for replacements like (reg X)->(subreg (reg X))
!      done by regmove, so we must special case shared ASM_OPERANDS.  */
  
!   if (GET_CODE (x) == PARALLEL)
      {
!       for (j = XVECLEN (x, 0) - 1; j >= 0; j--)
! 	{
! 	  if (j && GET_CODE (XVECEXP (x, 0, j)) == SET
! 	      && GET_CODE (SET_SRC (XVECEXP (x, 0, j))) == ASM_OPERANDS)
! 	    {
! 	      /* Verify that operands are really shared.  */
! 	      if (ASM_OPERANDS_INPUT_VEC (SET_SRC (XVECEXP (x, 0, 0))) !=
! 		  ASM_OPERANDS_INPUT_VEC (SET_SRC (XVECEXP (x, 0, j))))
! 		abort ();
! 	      validate_replace_rtx_1 (&SET_DEST (XVECEXP (x, 0, j)),
! 				      from, to, object);
! 	    }
! 	  else
! 	    validate_replace_rtx_1 (&XVECEXP (x, 0, j), from, to, object);
! 	}
      }
+   else
+     for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+       {
+ 	if (fmt[i] == 'e')
+ 	  validate_replace_rtx_1 (&XEXP (x, i), from, to, object);
+ 	else if (fmt[i] == 'E')
+ 	  for (j = XVECLEN (x, i) - 1; j >= 0; j--)
+ 	    validate_replace_rtx_1 (&XVECEXP (x, i, j), from, to, object);
+       }
  
    /* If we didn't substitute, there is nothing more to do.  */
    if (num_changes == prev_changes)