* ifcvt.c (dead_or_predicable): Use df_simulate_find_defs and

	df_simulate_find_noclobber_defs as appropriate.  Keep track of an
	extra set merge_set_noclobber, and use it to relax the final test
	slightly.
	* df.h (df_simulate_find_noclobber_defs): Declare.
	* df-problems.c (df_simulate_find_defs): Don't ignore partial or
	conditional defs.
	(df_simulate_find_noclobber_defs): New function.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@158639 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2684bec6faaa5b93ef68083596de9f7844cd9197..bf74e843e2743f459c9e608ad58237bdd6606f5b 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2010-04-22  Bernd Schmidt  <bernds@codesourcery.com>
+
+       * ifcvt.c (dead_or_predicable): Use df_simulate_find_defs and
+       df_simulate_find_noclobber_defs as appropriate.  Keep track of an
+       extra set merge_set_noclobber, and use it to relax the final test
+       slightly.
+       * df.h (df_simulate_find_noclobber_defs): Declare.
+       * df-problems.c (df_simulate_find_defs): Don't ignore partial or
+       conditional defs.
+       (df_simulate_find_noclobber_defs): New function.
+
 2010-04-22  Uros Bizjak  <ubizjak@gmail.com>
 
        * config/i386/i386.md: Use {} around multi-line preparation statements.

diff --git a/gcc/df-problems.c b/gcc/df-problems.c
index e0ec16778f0d1bf251dc69a4b03f4915624a3e5d..fb899096e4986a802b3f199c809976bb89a4fa90 100644 (file)
--- a/gcc/df-problems.c
+++ b/gcc/df-problems.c
@@ -3745,9 +3745,22 @@ df_simulate_find_defs (rtx insn, bitmap defs)
   for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
     {
       df_ref def = *def_rec;
-      /* If the def is to only part of the reg, it does
-        not kill the other defs that reach here.  */
-      if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
+      bitmap_set_bit (defs, DF_REF_REGNO (def));
+    }
+}
+
+/* Find the set of real DEFs, which are not clobbers, for INSN.  */
+
+void
+df_simulate_find_noclobber_defs (rtx insn, bitmap defs)
+{
+  df_ref *def_rec;
+  unsigned int uid = INSN_UID (insn);
+
+  for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      if (!(DF_REF_FLAGS (def) & (DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER)))
        bitmap_set_bit (defs, DF_REF_REGNO (def));
     }
 }
@@ -3939,7 +3952,7 @@ df_simulate_one_insn_forwards (basic_block bb, rtx insn, bitmap live)
      while here the scan is performed forwards!  So, first assume that the
      def is live, and if this is not true REG_UNUSED notes will rectify the
      situation.  */
-  df_simulate_find_defs (insn, live);
+  df_simulate_find_noclobber_defs (insn, live);
 
   /* Clear all of the registers that go dead.  */
   for (link = REG_NOTES (insn); link; link = XEXP (link, 1))

diff --git a/gcc/df.h b/gcc/df.h
index 194cbcf26393c73d266f5a237666d63f9e2161be..c73f00fe6cebb9481173b9b803d0651dbae0f42a 100644 (file)
--- a/gcc/df.h
+++ b/gcc/df.h
@@ -978,6 +978,7 @@ extern void df_note_add_problem (void);
 extern void df_md_add_problem (void);
 extern void df_md_simulate_artificial_defs_at_top (basic_block, bitmap);
 extern void df_md_simulate_one_insn (basic_block, rtx, bitmap);
+extern void df_simulate_find_noclobber_defs (rtx, bitmap);
 extern void df_simulate_find_defs (rtx, bitmap);
 extern void df_simulate_defs (rtx, bitmap);
 extern void df_simulate_uses (rtx, bitmap);

diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c
index 0c2d437a9dcb632c047073cb7de7e88a17573045..dcf44b8facf83f0b7b0e2391f02d22eb662c141c 100644 (file)
--- a/gcc/ifcvt.c
+++ b/gcc/ifcvt.c
@@ -3994,7 +3994,7 @@ dead_or_predicable (basic_block test_bb, basic_block merge_bb,
         that any registers modified are dead at the branch site.  */
 
       rtx insn, cond, prev;
-      bitmap merge_set, test_live, test_set;
+      bitmap merge_set, merge_set_noclobber, test_live, test_set;
       unsigned i, fail = 0;
       bitmap_iterator bi;
 
@@ -4030,11 +4030,14 @@ dead_or_predicable (basic_block test_bb, basic_block merge_bb,
 
       /* Collect:
           MERGE_SET = set of registers set in MERGE_BB
+          MERGE_SET_NOCLOBBER = like MERGE_SET, but only includes registers
+            that are really set, not just clobbered.
           TEST_LIVE = set of registers live at EARLIEST
-          TEST_SET  = set of registers set between EARLIEST and the
-                      end of the block.  */
+          TEST_SET = set of registers set between EARLIEST and the
+            end of the block.  */
 
       merge_set = BITMAP_ALLOC (&reg_obstack);
+      merge_set_noclobber = BITMAP_ALLOC (&reg_obstack);
       test_live = BITMAP_ALLOC (&reg_obstack);
       test_set = BITMAP_ALLOC (&reg_obstack);
 
@@ -4051,13 +4054,8 @@ dead_or_predicable (basic_block test_bb, basic_block merge_bb,
        {
          if (NONDEBUG_INSN_P (insn))
            {
-             unsigned int uid = INSN_UID (insn);
-             df_ref *def_rec;
-             for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
-               {
-                 df_ref def = *def_rec;
-                 bitmap_set_bit (merge_set, DF_REF_REGNO (def));
-               }
+             df_simulate_find_defs (insn, merge_set);
+             df_simulate_find_noclobber_defs (insn, merge_set_noclobber);
            }
        }
 
@@ -4065,7 +4063,7 @@ dead_or_predicable (basic_block test_bb, basic_block merge_bb,
         hard registers before reload.  */
       if (SMALL_REGISTER_CLASSES && ! reload_completed)
        {
-          EXECUTE_IF_SET_IN_BITMAP (merge_set, 0, i, bi)
+          EXECUTE_IF_SET_IN_BITMAP (merge_set_noclobber, 0, i, bi)
            {
              if (i < FIRST_PSEUDO_REGISTER
                  && ! fixed_regs[i]
@@ -4085,7 +4083,7 @@ dead_or_predicable (basic_block test_bb, basic_block merge_bb,
        {
          if (INSN_P (insn))
            {
-             df_simulate_find_defs (insn, test_set);
+             df_simulate_find_noclobber_defs (insn, test_set);
              df_simulate_one_insn_backwards (test_bb, insn, test_live);
            }
          prev = PREV_INSN (insn);
@@ -4094,16 +4092,19 @@ dead_or_predicable (basic_block test_bb, basic_block merge_bb,
        }
 
       /* We can perform the transformation if
-          MERGE_SET & (TEST_SET | TEST_LIVE)
+          MERGE_SET_NOCLOBBER & TEST_SET
+        and
+          MERGE_SET & TEST_LIVE)
         and
           TEST_SET & DF_LIVE_IN (merge_bb)
         are empty.  */
 
-      if (bitmap_intersect_p (test_set, merge_set)
+      if (bitmap_intersect_p (test_set, merge_set_noclobber)
          || bitmap_intersect_p (test_live, merge_set)
          || bitmap_intersect_p (test_set, df_get_live_in (merge_bb)))
        fail = 1;
 
+      BITMAP_FREE (merge_set_noclobber);
       BITMAP_FREE (merge_set);
       BITMAP_FREE (test_live);
       BITMAP_FREE (test_set);