Non-dead stores eliminated with cond-exec

[Richard Henderson]

On Thu, May 25, 2000 at 06:13:36PM +0100, Richard Earnshaw wrote:
> At the end of if_convert we update the global life info and remove any new 
> dead code that we find.  However, propagate_one_insn () notes that insn 
> 2013 stores into mem(r12+12), but doesn't note that this is conditional.  
> Hence it appears that insn 1995 is redundant, so it gets incorrectly 
> deleted.
> 
> I think we need to track the conditional nature of stores as we do for 
> registers in this case.

That would be most ideal yes.  The minimal fix is not to
record the memory as dead.


r~


	* flow.c (mark_set_1): Don't record conditionally dead memory.

Index: flow.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/flow.c,v
retrieving revision 1.291
diff -c -p -d -r1.291 flow.c
*** flow.c	2000/05/25 21:38:48	1.291
--- flow.c	2000/05/25 23:17:08
*************** mark_set_1 (pbi, code, reg, cond, insn, 
*** 4252,4257 ****
--- 4252,4259 ----
  	invalidate_mems_from_autoinc (pbi, insn);
  
        if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
+ 	  /* ??? With more effort we could track conditional memory life.  */
+ 	  && ! cond
  	  /* We do not know the size of a BLKmode store, so we do not track
  	     them for redundant store elimination.  */
  	  && GET_MODE (reg) != BLKmode