re PR middle-end/58335 (S/390: reload vs lra regression - testcase builtin-in-setjmp)

2013-09-12  Vladimir Makarov  <vmakarov@redhat.com>

	PR middle-end/58335
	* lra-eliminations (remove_reg_equal_offset_note): New.
	(eliminate_regs_in_insn): Rewrite frame pointer to hard frame
	pointer elimination with using remove_reg_equal_offset_note.

From-SVN: r202536

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a4440a01c896f63d9952e3604497fac53be662cd..4a3fca2f193f03b2874b3d939f42420e8aeadc18 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2013-09-12  Vladimir Makarov  <vmakarov@redhat.com>
+
+       PR middle-end/58335
+       * lra-eliminations (remove_reg_equal_offset_note): New.
+       (eliminate_regs_in_insn): Rewrite frame pointer to hard frame
+       pointer elimination with using remove_reg_equal_offset_note.
+
 2013-09-12  DJ Delorie  <dj@redhat.com>
 
        * config/msp430/: New port.

diff --git a/gcc/lra-eliminations.c b/gcc/lra-eliminations.c
index a59ab6eaccaa4c8730391dba3a0d8d55e1ea7391..f2a57511cbda8423ce0b5425fbf5373d3b67431e 100644 (file)
--- a/gcc/lra-eliminations.c
+++ b/gcc/lra-eliminations.c
@@ -745,13 +745,42 @@ mark_not_eliminable (rtx x)
 
 \f
 
+#ifdef HARD_FRAME_POINTER_REGNUM
+
+/* Find offset equivalence note for reg WHAT in INSN and return the
+   found elmination offset.  If the note is not found, return NULL.
+   Remove the found note.  */
+static rtx
+remove_reg_equal_offset_note (rtx insn, rtx what)
+{
+  rtx link, *link_loc;
+
+  for (link_loc = &REG_NOTES (insn);
+       (link = *link_loc) != NULL_RTX;
+       link_loc = &XEXP (link, 1))
+    if (REG_NOTE_KIND (link) == REG_EQUAL
+       && GET_CODE (XEXP (link, 0)) == PLUS
+       && XEXP (XEXP (link, 0), 0) == what
+       && CONST_INT_P (XEXP (XEXP (link, 0), 1)))
+      {
+       *link_loc = XEXP (link, 1);
+       return XEXP (XEXP (link, 0), 1);
+      }
+  return NULL_RTX;
+}
+
+#endif
+
 /* Scan INSN and eliminate all eliminable hard registers in it.
 
    If REPLACE_P is true, do the replacement destructively.  Also
    delete the insn as dead it if it is setting an eliminable register.
 
    If REPLACE_P is false, just update the offsets while keeping the
-   base register the same.  */
+   base register the same.  Attach the note about used elimination for
+   insns setting frame pointer to update elimination easy (without
+   parsing already generated elimination insns to find offset
+   previously used) in future.  */
 
 static void
 eliminate_regs_in_insn (rtx insn, bool replace_p)
@@ -790,59 +819,44 @@ eliminate_regs_in_insn (rtx insn, bool replace_p)
       if (ep->from == FRAME_POINTER_REGNUM
          && ep->to == HARD_FRAME_POINTER_REGNUM)
        {
+         rtx src = SET_SRC (old_set);
+         rtx off = remove_reg_equal_offset_note (insn, ep->to_rtx);
+
          if (replace_p)
            {
              SET_DEST (old_set) = ep->to_rtx;
              lra_update_insn_recog_data (insn);
              return;
            }
-         else
+         else if (off != NULL_RTX
+                  || src == ep->to_rtx
+                  || (GET_CODE (src) == PLUS
+                      && XEXP (src, 1) == ep->to_rtx
+                      && CONST_INT_P (XEXP (src, 1))))
            {
-             rtx base = SET_SRC (old_set);
-             HOST_WIDE_INT offset = 0;
-             rtx base_insn = insn;
-
-             while (base != ep->to_rtx)
+             HOST_WIDE_INT offset = (off != NULL_RTX
+                                     ? INTVAL (off)
+                                     : src == ep->to_rtx
+                                     ? 0 : INTVAL (XEXP (src, 1)));
+             
+             offset -= (ep->offset - ep->previous_offset);
+             src = plus_constant (Pmode, ep->to_rtx, offset);
+             
+             /* First see if this insn remains valid when we make
+                the change.  If not, keep the INSN_CODE the same
+                and let the constraint pass fit it up.  */
+             validate_change (insn, &SET_SRC (old_set), src, 1);
+             validate_change (insn, &SET_DEST (old_set),
+                              ep->from_rtx, 1);
+             if (! apply_change_group ())
                {
-                 rtx prev_insn, prev_set;
-
-                 if (GET_CODE (base) == PLUS && CONST_INT_P (XEXP (base, 1)))
-                   {
-                     offset += INTVAL (XEXP (base, 1));
-                     base = XEXP (base, 0);
-                   }
-                 else if ((prev_insn = prev_nonnote_insn (base_insn)) != 0
-                          && (prev_set = single_set (prev_insn)) != 0
-                          && rtx_equal_p (SET_DEST (prev_set), base))
-                   {
-                     base = SET_SRC (prev_set);
-                     base_insn = prev_insn;
-                   }
-                 else
-                   break;
-               }
-
-             if (base == ep->to_rtx)
-               {
-                 rtx src;
-
-                 offset -= (ep->offset - ep->previous_offset);
-                 src = plus_constant (Pmode, ep->to_rtx, offset);
-
-                 /* First see if this insn remains valid when we make
-                    the change.  If not, keep the INSN_CODE the same
-                    and let the constraint pass fit it up.  */
-                 validate_change (insn, &SET_SRC (old_set), src, 1);
-                 validate_change (insn, &SET_DEST (old_set),
-                                  ep->from_rtx, 1);
-                 if (! apply_change_group ())
-                   {
-                     SET_SRC (old_set) = src;
-                     SET_DEST (old_set) = ep->from_rtx;
-                   }
-                 lra_update_insn_recog_data (insn);
-                 return;
+                 SET_SRC (old_set) = src;
+                 SET_DEST (old_set) = ep->from_rtx;
                }
+             lra_update_insn_recog_data (insn);
+             /* Add offset note for future updates.  */
+             add_reg_note (insn, REG_EQUAL, src);
+             return;
            }