RESEND: [Patch] fix in storing function return register in a temp when register classes are small

[Igor Shevlyakov]

Hi folks,

I encountered a problem in SH codegeneration which could be fixed by
the patch. And it's correct to have that kind of check in general.
Code I fixed was inserting pseudo reg to hold function return values
if we have SMALL_REGISTER_CLASSES. It was looking for patterns like:

set r0 = call f
set blahh = r0

and changing it to 

set ro = call f
set rtemp = r0
set blah = rtemp

But it fails to find a pattern

set r0 = call f
set sp = sp + const
set blahh = r0

So I fixed that:

diff:

Index: egcs/gcc/function.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/function.c,v
retrieving revision 1.264
diff -c -3 -p -r1.264 function.c
*** function.c	2001/04/15 08:37:34	1.264
--- function.c	2001/04/20 02:01:17
*************** fixup_var_refs_insn (insn, var, promoted
*** 1797,1802 ****
--- 1797,1808 ----
  		   && GET_CODE (PATTERN (insn)) == PARALLEL
  		   && GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) == SET)
  	    call_dest = SET_DEST (XVECEXP (PATTERN (insn), 0, 0));
+ 		    call_dest = SET_DEST (XVECEXP (PATTERN (insn), 0, 0));
+ 	  else if (call_dest !=0 && GET_CODE(insn) == INSN &&
+ 		   GET_CODE(PATTERN(insn)) == SET &&
+ 		   GET_CODE (XEXP (PATTERN (insn), 0)) == REG &&
+ 		   REGNO(XEXP (PATTERN (insn), 0)) == STACK_POINTER_REGNUM)
+ 	    ; //keep call_dest since it's set sp = sp + adj
  	  else
  	    call_dest = 0;
  	}

======================================
ChangeLog:

2001-04-19  Igor Shevlyakov <igor@windriver.com>
	* function.c: (fixup_var_refs_insn): Not to stop the search for
	usage of function return register on adjusting stack frame after call.

=========================================
Regards,
Igor Shevlyakov