re PR rtl-optimization/48542 (unchanged variables in code which calls setjmp may…

re PR rtl-optimization/48542 (unchanged variables in code which calls setjmp may be clobbered (including the return-address))

	PR rtl-optimization/48542
	* reload.c (find_equiv_reg): Stop looking when finding a
	setjmp-type call.
	* reload1.c (reload_as_needed): Invalidate all reload
	registers when crossing a setjmp-type call.

From-SVN: r175132

gcc/ChangeLog

+2011-06-17  Hans-Peter Nilsson  <hp@axis.com>
+
+	PR rtl-optimization/48542
+	* reload.c (find_equiv_reg): Stop looking when finding a
+	setjmp-type call.
+	* reload1.c (reload_as_needed): Invalidate all reload
+	registers when crossing a setjmp-type call.
+
 2011-06-16  Jeff Law  <law@redhat.com>
 
 	* tree-ssa-threadupdate.c (struct redirection_data): New field

gcc/reload.c

@@ -6791,6 +6791,15 @@ find_equiv_reg (rtx goal, rtx insn, enum reg_class rclass, int other,
 	  || num > PARAM_VALUE (PARAM_MAX_RELOAD_SEARCH_INSNS))
 	return 0;
 
+      /* Don't reuse register contents from before a setjmp-type
+	 function call; on the second return (from the longjmp) it
+	 might have been clobbered by a later reuse.  It doesn't
+	 seem worthwhile to actually go and see if it is actually
+	 reused even if that information would be readily available;
+	 just don't reuse it across the setjmp call.  */
+      if (CALL_P (p) && find_reg_note (p, REG_SETJMP, NULL_RTX))
+	return 0;
+
       if (NONJUMP_INSN_P (p)
 	  /* If we don't want spill regs ...  */
 	  && (! (reload_reg_p != 0

gcc/reload1.c

@@ -4844,6 +4844,13 @@ reload_as_needed (int live_known)
 	{
 	  AND_COMPL_HARD_REG_SET (reg_reloaded_valid, call_used_reg_set);
 	  AND_COMPL_HARD_REG_SET (reg_reloaded_valid, reg_reloaded_call_part_clobbered);
+
+	  /* If this is a call to a setjmp-type function, we must not
+	     reuse any reload reg contents across the call; that will
+	     just be clobbered by other uses of the register in later
+	     code, before the longjmp.  */
+	  if (find_reg_note (insn, REG_SETJMP, NULL_RTX))
+	    CLEAR_HARD_REG_SET (reg_reloaded_valid);
 	}
     }