[PATCH,committed] rs6000 stack tie artificial mem

[David Edelsohn]

	Following up on Jakub's patch for PR target/34225, this patch
ignores stack_tie in the RTL stream when considering memory.  STACK_TIE is
an artificial insn to represent a data dependence, not a real memory
operation.

Bootstrapped and regression tested on powerpc-ibm-aix5.3.0.0.

David

	* config/rs6000/rs6000.c (is_mem_ref): Ignore STACK_TIE.

Index: rs6000.c
===================================================================
*** rs6000.c	(revision 130785)
--- rs6000.c	(working copy)
*************** is_mem_ref (rtx pat)
*** 18383,18388 ****
--- 18383,18392 ----
    int i, j;
    bool ret = false;
  
+   if (GET_CODE (pat) == UNSPEC
+       && XINT (pat, 1) == UNSPEC_TIE)
+     return false;
+ 
    if (GET_CODE (pat) == MEM)
      return true;