regrename.c (scan_rtx_rtx): Skip to the next chain on encountering a terminated chain.

        * regrename.c (scan_rtx_rtx): Skip to the next chain on
        encountering a terminated chain.

From-SVN: r37473

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f0164266dde6f458916825ae3be90de52a01ca8e..60efafb3265e22ff2f898909ac07f0e829012d81 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2000-11-15  Graham Stott  <grahams@redhat.com>
+
+       * regrename.c (scan_rtx_rtx): Skip to the next chain on
+       encountering a terminated chain.
+
 2000-11-14  Mark Mitchell  <mark@codesourcery.com>
 
        * configure.in: Move check for V3 above check for C++ header-file

diff --git a/gcc/regrename.c b/gcc/regrename.c
index b3aa6c2f32a8630f34e54380db869825dde51c1b..c444af8326e1e5fcbf295620acddf906ac930bcf 100644 (file)
--- a/gcc/regrename.c
+++ b/gcc/regrename.c
@@ -307,62 +307,75 @@ scan_rtx_reg (insn, loc, class, action, type)
   for (p = &open_chains; *p;)
     {
       struct du_chain *this = *p;
-      int regno = REGNO (*this->loc);
-      int nregs = HARD_REGNO_NREGS (regno, GET_MODE (*this->loc));
-      int exact_match = (regno == this_regno && nregs == this_nregs);
 
-      if (regno + nregs <= this_regno
-         || this_regno + this_nregs <= regno)
-       p = &this->next_chain;
-      else if (action == mark_read)
-       {
-         if (! exact_match)
-           abort ();
-         if (class == NO_REGS)
-           abort ();
+      /* Check if the chain has been terminated if it has then skip to
+        the next chain.
 
-         this = (struct du_chain *)
-           obstack_alloc (&rename_obstack, sizeof (struct du_chain));
-         this->next_use = *p;
-         this->next_chain = (*p)->next_chain;
-         this->loc = loc;
-         this->insn = insn;
-         this->class = class;
-         this->need_caller_save_reg = 0;
-         *p = this;
-         return;
-       }
-      else if (action != terminate_overlapping_read || ! exact_match)
-       {
-         struct du_chain *next = this->next_chain;
-
-         /* Whether the terminated chain can be used for renaming
-            depends on the action and this being an exact match.
-            In either case, we remove this element from open_chains.  */
+        This can happen when we've already appended the location to
+        the chain in Step 3, but are trying to hide in-out operands
+        from terminate_write in Step 5.  */
 
-         if ((action == terminate_dead || action == terminate_write)
-             && exact_match)
+      if (*this->loc == cc0_rtx)
+       p = &this->next_chain;
+      else
+        {
+         int regno = REGNO (*this->loc);
+         int nregs = HARD_REGNO_NREGS (regno, GET_MODE (*this->loc));
+         int exact_match = (regno == this_regno && nregs == this_nregs);
+
+         if (regno + nregs <= this_regno
+             || this_regno + this_nregs <= regno)
+           p = &this->next_chain;
+         else if (action == mark_read)
            {
-             this->next_chain = closed_chains;
-             closed_chains = this;
-             if (rtl_dump_file)
-               fprintf (rtl_dump_file,
-                        "Closing chain %s at insn %d (%s)\n",
-                        reg_names[REGNO (*this->loc)], INSN_UID (insn),
-                        scan_actions_name[(int) action]);
+             if (! exact_match)
+               abort ();
+             if (class == NO_REGS)
+               abort ();
+
+             this = (struct du_chain *)
+               obstack_alloc (&rename_obstack, sizeof (struct du_chain));
+             this->next_use = *p;
+             this->next_chain = (*p)->next_chain;
+             this->loc = loc;
+             this->insn = insn;
+             this->class = class;
+             this->need_caller_save_reg = 0;
+             *p = this;
+             return;
            }
-         else
+         else if (action != terminate_overlapping_read || ! exact_match)
            {
-             if (rtl_dump_file)
-               fprintf (rtl_dump_file,
-                        "Discarding chain %s at insn %d (%s)\n",
-                        reg_names[REGNO (*this->loc)], INSN_UID (insn),
-                        scan_actions_name[(int) action]);
+             struct du_chain *next = this->next_chain;
+
+             /* Whether the terminated chain can be used for renaming
+                depends on the action and this being an exact match.
+                In either case, we remove this element from open_chains.  */
+
+             if ((action == terminate_dead || action == terminate_write)
+                 && exact_match)
+               {
+                 this->next_chain = closed_chains;
+                 closed_chains = this;
+                 if (rtl_dump_file)
+                   fprintf (rtl_dump_file,
+                            "Closing chain %s at insn %d (%s)\n",
+                            reg_names[REGNO (*this->loc)], INSN_UID (insn),
+                            scan_actions_name[(int) action]);
+               }
+             else
+               {
+                 if (rtl_dump_file)
+                   fprintf (rtl_dump_file,
+                            "Discarding chain %s at insn %d (%s)\n",
+                            reg_names[REGNO (*this->loc)], INSN_UID (insn),
+                            scan_actions_name[(int) action]);
+               }
+             *p = next;
            }
-         *p = next;
+         else
+           p = &this->next_chain;
        }
-      else
-       p = &this->next_chain;
     }
 }