* flow.c (find_unreachable_blocks): New function.

[pf3gnuchains/gcc-fork.git] / gcc / loop.c

diff --git a/gcc/loop.c b/gcc/loop.c
index 34bc862..82f09f3 100644 (file)
--- a/gcc/loop.c
+++ b/gcc/loop.c
@@ -52,6 +52,7 @@ Boston, MA 02111-1307, USA.  */
 #include "cselib.h"
 #include "except.h"
 #include "toplev.h"
+#include "predict.h"
 
 #define LOOP_REG_LIFETIME(LOOP, REGNO) \
 ((REGNO_LAST_LUID (REGNO) - REGNO_FIRST_LUID (REGNO)))
@@ -4305,6 +4306,11 @@ strength_reduce (loop, flags)
         provided all givs are reduced.  */
       bl->eliminable = loop_biv_eliminable_p (loop, bl, threshold, insn_count);
 
+      /* This will be true at the end, if all givs which depend on this
+        biv have been strength reduced.
+        We can't (currently) eliminate the biv unless this is so.  */
+      bl->all_reduced = 1;
+
       /* Check each extension dependent giv in this class to see if its
         root biv is safe from wrapping in the interior mode.  */
       check_ext_dependant_givs (bl, loop_info);
@@ -4312,11 +4318,6 @@ strength_reduce (loop, flags)
       /* Combine all giv's for this iv_class.  */
       combine_givs (regs, bl);
 
-      /* This will be true at the end, if all givs which depend on this
-        biv have been strength reduced.
-        We can't (currently) eliminate the biv unless this is so.  */
-      bl->all_reduced = 1;
-
       for (v = bl->giv; v; v = v->next_iv)
        {
          struct induction *tv;
@@ -4498,6 +4499,18 @@ strength_reduce (loop, flags)
     doloop_optimize (loop);
 #endif  /* HAVE_doloop_end  */
 
+  /* In case number of iterations is known, drop branch prediction note
+     in the branch.  Do that only in second loop pass, as loop unrolling
+     may change the number of iterations performed.  */
+  if ((flags & LOOP_BCT)
+      && loop_info->n_iterations / loop_info->unroll_number > 1)
+    {
+      int n = loop_info->n_iterations / loop_info->unroll_number;
+      predict_insn (PREV_INSN (loop->end),
+                   PRED_LOOP_ITERATIONS,
+                   REG_BR_PROB_BASE - REG_BR_PROB_BASE / n);
+    }
+
   if (loop_dump_stream)
     fprintf (loop_dump_stream, "\n");
 
@@ -6647,6 +6660,7 @@ check_ext_dependant_givs (bl, loop_info)
                         INSN_UID (v->insn), why);
              }
            v->ignore = 1;
+           bl->all_reduced = 0;
          }
       }
 }