* cse.c (delete_trivially_dead_insn): Don't iterate.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@94498 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8d618f5..4fa04ff 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2005-01-31  Kazu Hirata  <kazu@cs.umass.edu>
+
+       * cse.c (delete_trivially_dead_insn): Don't iterate.
+
 2005-01-31  Andrew Pinski  <pinskia@physics.uc.edu>
 
        * config/rs6000/rs6000.md (copysignsf3): New expand.

diff --git a/gcc/cse.c b/gcc/cse.c
index 427ab0b..ca0bade 100644 (file)
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -7268,7 +7268,7 @@ delete_trivially_dead_insns (rtx insns, int nreg)
   int *counts;
   rtx insn, prev;
   int in_libcall = 0, dead_libcall = 0;
-  int ndead = 0, nlastdead, niterations = 0;
+  int ndead = 0;
 
   timevar_push (TV_DELETE_TRIVIALLY_DEAD);
   /* First count the number of times each register is used.  */
@@ -7276,65 +7276,59 @@ delete_trivially_dead_insns (rtx insns, int nreg)
   for (insn = next_real_insn (insns); insn; insn = next_real_insn (insn))
     count_reg_usage (insn, counts, 1);
 
-  do
-    {
-      nlastdead = ndead;
-      niterations++;
-      /* Go from the last insn to the first and delete insns that only set unused
-        registers or copy a register to itself.  As we delete an insn, remove
-        usage counts for registers it uses.
-
-        The first jump optimization pass may leave a real insn as the last
-        insn in the function.   We must not skip that insn or we may end
-        up deleting code that is not really dead.  */
-      insn = get_last_insn ();
-      if (! INSN_P (insn))
-       insn = prev_real_insn (insn);
+  /* Go from the last insn to the first and delete insns that only set unused
+     registers or copy a register to itself.  As we delete an insn, remove
+     usage counts for registers it uses.
 
-      for (; insn; insn = prev)
-       {
-         int live_insn = 0;
+     The first jump optimization pass may leave a real insn as the last
+     insn in the function.   We must not skip that insn or we may end
+     up deleting code that is not really dead.  */
+  insn = get_last_insn ();
+  if (! INSN_P (insn))
+    insn = prev_real_insn (insn);
 
-         prev = prev_real_insn (insn);
+  for (; insn; insn = prev)
+    {
+      int live_insn = 0;
 
-         /* Don't delete any insns that are part of a libcall block unless
-            we can delete the whole libcall block.
+      prev = prev_real_insn (insn);
 
-            Flow or loop might get confused if we did that.  Remember
-            that we are scanning backwards.  */
-         if (find_reg_note (insn, REG_RETVAL, NULL_RTX))
-           {
-             in_libcall = 1;
-             live_insn = 1;
-             dead_libcall = dead_libcall_p (insn, counts);
-           }
-         else if (in_libcall)
-           live_insn = ! dead_libcall;
-         else
-           live_insn = insn_live_p (insn, counts);
+      /* Don't delete any insns that are part of a libcall block unless
+        we can delete the whole libcall block.
+
+        Flow or loop might get confused if we did that.  Remember
+        that we are scanning backwards.  */
+      if (find_reg_note (insn, REG_RETVAL, NULL_RTX))
+       {
+         in_libcall = 1;
+         live_insn = 1;
+         dead_libcall = dead_libcall_p (insn, counts);
+       }
+      else if (in_libcall)
+       live_insn = ! dead_libcall;
+      else
+       live_insn = insn_live_p (insn, counts);
 
-         /* If this is a dead insn, delete it and show registers in it aren't
-            being used.  */
+      /* If this is a dead insn, delete it and show registers in it aren't
+        being used.  */
 
-         if (! live_insn)
-           {
-             count_reg_usage (insn, counts, -1);
-             delete_insn_and_edges (insn);
-             ndead++;
-           }
+      if (! live_insn)
+       {
+         count_reg_usage (insn, counts, -1);
+         delete_insn_and_edges (insn);
+         ndead++;
+       }
 
-         if (find_reg_note (insn, REG_LIBCALL, NULL_RTX))
-           {
-             in_libcall = 0;
-             dead_libcall = 0;
-           }
+      if (find_reg_note (insn, REG_LIBCALL, NULL_RTX))
+       {
+         in_libcall = 0;
+         dead_libcall = 0;
        }
     }
-  while (ndead != nlastdead);
 
   if (dump_file && ndead)
-    fprintf (dump_file, "Deleted %i trivially dead insns; %i iterations\n",
-            ndead, niterations);
+    fprintf (dump_file, "Deleted %i trivially dead insns\n",
+            ndead);
   /* Clean up.  */
   free (counts);
   timevar_pop (TV_DELETE_TRIVIALLY_DEAD);