Re: optimization/10592: [arm] caller-save incorrectly handles a reloaded SET_DEST operand

[Richard Earnshaw <rearnsha@arm.com>]

The following reply was made to PR optimization/10592; it has been noted by GNATS.

From: Richard Earnshaw <rearnsha@arm.com>
To: gcc-bugs@gcc.gnu.org, gcc-gnats@gcc.gnu.org, nobody@gcc.gnu.org,
        ryan.pipkin@inet.com, law@redhat.com
Cc: Richard.Earnshaw@arm.com
Subject: Re: optimization/10592: [arm] caller-save incorrectly handles a 
 reloaded SET_DEST operand
Date: Fri, 02 May 2003 15:02:10 +0100

 This is a multipart MIME message.
 
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 Content-Type: text/plain; charset=us-ascii
 
 This patch implements the idea I just suggested, it does indeed seem to 
 solve the problem:
 
 With the patch, the relevant bit of the code is now:
 
         str     ip, [fp, #-44]
         bl      strncpy
         ldr     ip, [fp, #-44]
         add     r2, r9, #156
         add     lr, r9, #16
         str     r2, [ip, #540]
 
 
 I'll do a full testsuite run to check for regressions.
 
 <date>  Richard Earnshaw  <rearnsha@arm.com>
 
 	* caller-save.c (mark_referenced_regs): Don't short-circuit a reg
 	or subreg in SET_DEST if it isn't a hard register.
 
 R.
 
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 Content-Type: text/plain ; name="caller-save.patch"; charset=us-ascii
 Content-Description: caller-save.patch
 Content-Disposition: attachment; filename="caller-save.patch"
 
 Index: caller-save.c
 ===================================================================
 RCS file: /cvs/gcc/gcc/gcc/caller-save.c,v
 retrieving revision 1.54
 diff -p -r1.54 caller-save.c
 *** caller-save.c	16 Dec 2002 18:19:05 -0000	1.54
 --- caller-save.c	2 May 2003 13:57:25 -0000
 *************** mark_referenced_regs (x)
 *** 575,582 ****
       {
         x = SET_DEST (x);
         code = GET_CODE (x);
 !       if (code == REG || code == PC || code == CC0
   	  || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG
   	      /* If we're setting only part of a multi-word register,
   		 we shall mark it as referenced, because the words
   		 that are not being set should be restored.  */
 --- 575,584 ----
       {
         x = SET_DEST (x);
         code = GET_CODE (x);
 !       if ((code == REG && REGNO (x) < FIRST_PSEUDO_REGISTER)
 ! 	  || code == PC || code == CC0
   	  || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG
 + 	      && REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER
   	      /* If we're setting only part of a multi-word register,
   		 we shall mark it as referenced, because the words
   		 that are not being set should be restored.  */
 
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