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Date: Tue, 06 May 2003 01:16:00 -0000
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Cc: gcc-prs@gcc.gnu.org,
From: Pete Gonzalez <gonz@ratloop.com>
Subject: Re: inline-asm/10396: Constraint alternatives cause error "
  `asm' operand requires impossible reload"
Reply-To: Pete Gonzalez <gonz@ratloop.com>
X-SW-Source: 2003-05/txt/msg00331.txt.bz2
List-Id: <gcc-prs.sourceware.org>

The following reply was made to PR inline-asm/10396; it has been noted by GNATS.

From: Pete Gonzalez <gonz@ratloop.com>
To: gcc-gnats@gcc.gnu.org,gcc-bugs@gcc.gnu.org,nobody@gcc.gnu.org,
 gcc-prs@gcc.gnu.org,gonz@ratloop.com
Cc:  
Subject: Re: inline-asm/10396: Constraint alternatives cause error "
  `asm' operand requires impossible reload"
Date: Mon, 05 May 2003 21:05:56 -0400

 I tried the example again with the GCC 3.3 prerelease (20030428),
 but the "impossible reload" error is still being generated.
 
 For reference, here is the section from gcc/reload1.c which produces
 the error message:
 
 	      /* Substitute the chosen reload regs from reload_reg_rtx
 		 into the insn's body (or perhaps into the bodies of other
 		 load and store insn that we just made for reloading
 		 and that we moved the structure into).  */
 	      subst_reloads (insn);
 
 	      /* If this was an ASM, make sure that all the reload insns
 		 we have generated are valid.  If not, give an error
 		 and delete them.  */
 
 	      if (asm_noperands (PATTERN (insn)) >= 0)
 		for (p = NEXT_INSN (prev); p != next; p = NEXT_INSN (p))
 		  if (p != insn && INSN_P (p)
 		      && GET_CODE (PATTERN (p)) != USE
 		      && (recog_memoized (p) < 0
 			  || (extract_insn (p), ! constrain_operands (1))))
 		    {
 		      error_for_asm (insn,
 				     "`asm' operand requires impossible reload");
 		      delete_insn (p);
 		    }
 
 Once again, each of the constraint alternatives works fine by itself;
 it is only the combination of three alternatives that introduces the
 error.