This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[tree-ssa] CALL_EXPR support for operand_equal_p


One of the pieces of infrastructure we need to be able to eliminate
useless or redundant calls to "const" functions.  In simplest terms
this allows us to use operand_equal_p to determine if two given CALL_EXPRs
call the same function with the same arguments.

The usual testing has been done with this patch in a tree which has the
rest of the infrastructure required to remove useless or redundant calls
to "const" functions.

	* fold-const.c (operand_equal_p): Handle CALL_EXPRs.

Index: fold-const.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/fold-const.c,v
retrieving revision 1.213.2.30
diff -c -3 -p -r1.213.2.30 fold-const.c
*** fold-const.c	9 Jun 2003 22:40:33 -0000	1.213.2.30
--- fold-const.c	12 Jun 2003 04:42:17 -0000
*************** operand_equal_p (arg0, arg1, only_const)
*** 2016,2021 ****
--- 2016,2046 ----
  	case RTL_EXPR:
  	  return rtx_equal_p (RTL_EXPR_RTL (arg0), RTL_EXPR_RTL (arg1));
  
+ 	case CALL_EXPR:
+ 	  /* If the CALL_EXPRs call different functions, then they
+ 	     clearly can not be equal.  */
+ 	  if (! operand_equal_p (TREE_OPERAND (arg0, 0),
+ 				 TREE_OPERAND (arg1, 0), 0))
+ 	    return 0;
+ 
+ 	  /* Now see if all the arguments are the same.  operand_equal_p
+ 	     does not handle TREE_LIST, so we walk the operands here
+ 	     feeding them to operand_equal_p.  */
+ 	  arg0 = TREE_OPERAND (arg0, 1);
+ 	  arg1 = TREE_OPERAND (arg1, 1);
+ 	  while (arg0 && arg1)
+ 	    {
+ 	      if (! operand_equal_p (TREE_VALUE (arg0), TREE_VALUE (arg1), 0))
+ 		return 0;
+ 
+ 	      arg0 = TREE_CHAIN (arg0);
+ 	      arg1 = TREE_CHAIN (arg1);
+ 	    }
+ 
+ 	  /* If we get here and both argument lists are exhausted 
+ 	     then the CALL_EXPRs are equal.  */
+ 	  return ! (arg0 || arg1);
+ 
  	default:
  	  return 0;
  	}







Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]