Fix combine EH related failure

[Alan Modra]

On Thu, Feb 12, 2004 at 11:39:32AM +1030, Alan Modra wrote:
> Fixes http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14119

As pointed out by rth on irc, my testing of PATTERN (i3) and
PATTERN (i2) against set0 and set1 was bogus, because these may have
been modified in place.  I really don't like combine moving instructions
around for no purpose as shown in the PR, but that's a secondary problem
compared to dropping REG_EH_REGION notes.  So..  This one just attacks
the REG_EH_REGION problem.

	PR optimization/14119
	* combine.c (try_combine): When attemting to fix unrecognized insns,
	don't delete SETs marked with REG_EH_REGION notes.

Bootstrapping etc. in progress.

Index: gcc/combine.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/combine.c,v
retrieving revision 1.408
diff -u -p -w -r1.408 combine.c
--- gcc/combine.c	3 Feb 2004 05:15:35 -0000	1.408
+++ gcc/combine.c	17 Feb 2004 01:06:54 -0000
@@ -2017,7 +2017,8 @@ try_combine (rtx i3, rtx i2, rtx i1, int
   insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes);
 
   /* If the result isn't valid, see if it is a PARALLEL of two SETs where
-     the second SET's destination is a register that is unused.  In that case,
+     the second SET's destination is a register that is unused and isn't
+     marked as an instruction that might trap in an EH region.  In that case,
      we just need the first SET.   This can occur when simplifying a divmod
      insn.  We *must* test for this case here because the code below that
      splits two independent SETs doesn't handle this case correctly when it
@@ -2033,11 +2034,14 @@ try_combine (rtx i3, rtx i2, rtx i1, int
     {
       rtx set0 = XVECEXP (newpat, 0, 0);
       rtx set1 = XVECEXP (newpat, 0, 1);
+      rtx note;
   
       if (((GET_CODE (SET_DEST (set1)) == REG
             && find_reg_note (i3, REG_UNUSED, SET_DEST (set1)))
           || (GET_CODE (SET_DEST (set1)) == SUBREG
               && find_reg_note (i3, REG_UNUSED, SUBREG_REG (SET_DEST (set1)))))
+	  && (!(note = find_reg_note (i3, REG_EH_REGION, NULL_RTX))
+	      || INTVAL (XEXP (note, 0)) <= 0)
           && ! side_effects_p (SET_SRC (set1)))
         {
           newpat = set0;
@@ -2049,6 +2053,8 @@ try_combine (rtx i3, rtx i2, rtx i1, int
                 || (GET_CODE (SET_DEST (set0)) == SUBREG
                     && find_reg_note (i3, REG_UNUSED,
                                       SUBREG_REG (SET_DEST (set0)))))
+	       && (!(note = find_reg_note (i3, REG_EH_REGION, NULL_RTX))
+		   || INTVAL (XEXP (note, 0)) <= 0)
               && ! side_effects_p (SET_SRC (set0)))
         {
           newpat = set1;

-- 
Alan Modra
IBM OzLabs - Linux Technology Centre