1 files changed, 169 insertions, 79 deletions

diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c
index fe3806066b1..2b10e18628e 100644
--- a/gcc/ifcvt.c
+++ b/gcc/ifcvt.c
@@ -84,9 +84,6 @@ static int cond_exec_changed_p;
 /* True if life data ok at present.  */
 static bool life_data_ok;
 
-/* The post-dominator relation on the original block numbers.  */
-static dominance_info post_dominators;
-
 /* Forward references.  */
 static int count_bb_insns (basic_block);
 static rtx first_active_insn (basic_block);
@@ -123,6 +120,7 @@ mark_loop_exit_edges (void)
   edge e;
   
   flow_loops_find (&loops, LOOP_TREE);
+  free_dominance_info (CDI_DOMINATORS);
   
   if (loops.num > 1)
     {
@@ -148,14 +146,14 @@ static int
 count_bb_insns (basic_block bb)
 {
   int count = 0;
-  rtx insn = bb->head;
+  rtx insn = BB_HEAD (bb);
 
   while (1)
     {
       if (GET_CODE (insn) == CALL_INSN || GET_CODE (insn) == INSN)
 	count++;
 
-      if (insn == bb->end)
+      if (insn == BB_END (bb))
 	break;
       insn = NEXT_INSN (insn);
     }
@@ -168,18 +166,18 @@ count_bb_insns (basic_block bb)
 static rtx
 first_active_insn (basic_block bb)
 {
-  rtx insn = bb->head;
+  rtx insn = BB_HEAD (bb);
 
   if (GET_CODE (insn) == CODE_LABEL)
     {
-      if (insn == bb->end)
+      if (insn == BB_END (bb))
 	return NULL_RTX;
       insn = NEXT_INSN (insn);
     }
 
   while (GET_CODE (insn) == NOTE)
     {
-      if (insn == bb->end)
+      if (insn == BB_END (bb))
 	return NULL_RTX;
       insn = NEXT_INSN (insn);
     }
@@ -195,8 +193,8 @@ first_active_insn (basic_block bb)
 static rtx
 last_active_insn (basic_block bb, int skip_use_p)
 {
-  rtx insn = bb->end;
-  rtx head = bb->head;
+  rtx insn = BB_END (bb);
+  rtx head = BB_HEAD (bb);
 
   while (GET_CODE (insn) == NOTE
 	 || GET_CODE (insn) == JUMP_INSN
@@ -407,13 +405,13 @@ cond_exec_process_if_block (ce_if_block_t * ce_info,
 
   /* Find the conditional jump to the ELSE or JOIN part, and isolate
      the test.  */
-  test_expr = cond_exec_get_condition (test_bb->end);
+  test_expr = cond_exec_get_condition (BB_END (test_bb));
   if (! test_expr)
     return FALSE;
 
   /* If the conditional jump is more than just a conditional jump,
      then we can not do conditional execution conversion on this block.  */
-  if (! onlyjump_p (test_bb->end))
+  if (! onlyjump_p (BB_END (test_bb)))
     return FALSE;
 
   /* Collect the bounds of where we're to search, skipping any labels, jumps
@@ -440,7 +438,7 @@ cond_exec_process_if_block (ce_if_block_t * ce_info,
 
   true_expr = test_expr;
 
-  false_code = reversed_comparison_code (true_expr, test_bb->end);
+  false_code = reversed_comparison_code (true_expr, BB_END (test_bb));
   if (false_code != UNKNOWN)
     false_expr = gen_rtx_fmt_ee (false_code, GET_MODE (true_expr),
 				 XEXP (true_expr, 0), XEXP (true_expr, 1));
@@ -452,12 +450,12 @@ cond_exec_process_if_block (ce_if_block_t * ce_info,
      conditional execution register from a comparison, it can do so here.  */
   IFCVT_MODIFY_TESTS (ce_info, true_expr, false_expr);
 
-  /* See if the conversion failed */
+  /* See if the conversion failed.  */
   if (!true_expr || !false_expr)
     goto fail;
 #endif
 
-  true_prob_val = find_reg_note (test_bb->end, REG_BR_PROB, NULL_RTX);
+  true_prob_val = find_reg_note (BB_END (test_bb), REG_BR_PROB, NULL_RTX);
   if (true_prob_val)
     {
       true_prob_val = XEXP (true_prob_val, 0);
@@ -491,11 +489,11 @@ cond_exec_process_if_block (ce_if_block_t * ce_info,
 
 	  /* If the conditional jump is more than just a conditional jump, then
 	     we can not do conditional execution conversion on this block.  */
-	  if (! onlyjump_p (bb->end))
+	  if (! onlyjump_p (BB_END (bb)))
 	    goto fail;
 
 	  /* Find the conditional jump and isolate the test.  */
-	  t = cond_exec_get_condition (bb->end);
+	  t = cond_exec_get_condition (BB_END (bb));
 	  if (! t)
 	    goto fail;
 
@@ -521,7 +519,7 @@ cond_exec_process_if_block (ce_if_block_t * ce_info,
 #ifdef IFCVT_MODIFY_MULTIPLE_TESTS
 	  IFCVT_MODIFY_MULTIPLE_TESTS (ce_info, bb, t, f);
 
-	  /* See if the conversion failed */
+	  /* See if the conversion failed.  */
 	  if (!t || !f)
 	    goto fail;
 #endif
@@ -563,7 +561,7 @@ cond_exec_process_if_block (ce_if_block_t * ce_info,
     }
 
 #ifdef IFCVT_MODIFY_FINAL
-  /* Do any machine dependent final modifications */
+  /* Do any machine dependent final modifications.  */
   IFCVT_MODIFY_FINAL (ce_info);
 #endif
 
@@ -602,6 +600,7 @@ struct noce_if_info
 };
 
 static rtx noce_emit_store_flag (struct noce_if_info *, rtx, int, int);
+static int noce_try_move (struct noce_if_info *);
 static int noce_try_store_flag (struct noce_if_info *);
 static int noce_try_addcc (struct noce_if_info *);
 static int noce_try_store_flag_constants (struct noce_if_info *);
@@ -674,7 +673,9 @@ noce_emit_store_flag (struct noce_if_info *if_info, rtx x, int reversep,
 			   || code == GEU || code == GTU), normalize);
 }
 
-/* Emit instruction to move an rtx into STRICT_LOW_PART.  */
+/* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
+   X is the destination/target and Y is the value to copy.  */
+
 static void
 noce_emit_move_insn (rtx x, rtx y)
 {
@@ -697,6 +698,60 @@ noce_emit_move_insn (rtx x, rtx y)
 		   GET_MODE_BITSIZE (inmode));
 }
 
+/* Unshare sequence SEQ produced by if conversion.  We care to mark
+   all arguments that may be shared with outer instruction stream.  */
+static void
+unshare_ifcvt_sequence (struct noce_if_info *if_info, rtx seq)
+{
+  set_used_flags (if_info->x);
+  set_used_flags (if_info->cond);
+  unshare_all_rtl_in_chain (seq);
+}
+
+/* Convert "if (a != b) x = a; else x = b" into "x = a" and
+   "if (a == b) x = a; else x = b" into "x = b".  */
+
+static int
+noce_try_move (struct noce_if_info *if_info)
+{
+  rtx cond = if_info->cond;
+  enum rtx_code code = GET_CODE (cond);
+  rtx y, seq;
+
+  if (code != NE && code != EQ)
+    return FALSE;
+
+  /* This optimization isn't valid if either A or B could be a NaN
+     or a signed zero.  */
+  if (HONOR_NANS (GET_MODE (if_info->x))
+      || HONOR_SIGNED_ZEROS (GET_MODE (if_info->x)))
+    return FALSE;
+
+  /* Check whether the operands of the comparison are A and in
+     either order.  */
+  if ((rtx_equal_p (if_info->a, XEXP (cond, 0))
+       && rtx_equal_p (if_info->b, XEXP (cond, 1)))
+      || (rtx_equal_p (if_info->a, XEXP (cond, 1))
+	  && rtx_equal_p (if_info->b, XEXP (cond, 0))))
+    {
+      y = (code == EQ) ? if_info->a : if_info->b;
+
+      /* Avoid generating the move if the source is the destination.  */
+      if (! rtx_equal_p (if_info->x, y))
+	{
+	  start_sequence ();
+	  noce_emit_move_insn (if_info->x, y);
+	  seq = get_insns ();
+	  unshare_ifcvt_sequence (if_info, seq);
+	  end_sequence ();
+	  emit_insn_before_setloc (seq, if_info->jump,
+				   INSN_LOCATOR (if_info->insn_a));
+	}
+      return TRUE;
+    }
+  return FALSE;
+}
+
 /* Convert "if (test) x = 1; else x = 0".
 
    Only try 0 and STORE_FLAG_VALUE here.  Other combinations will be
@@ -731,6 +786,7 @@ noce_try_store_flag (struct noce_if_info *if_info)
 	noce_emit_move_insn (if_info->x, target);
 
       seq = get_insns ();
+      unshare_ifcvt_sequence (if_info, seq);
       end_sequence ();
       emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATOR (if_info->insn_a));
 
@@ -861,6 +917,7 @@ noce_try_store_flag_constants (struct noce_if_info *if_info)
 	noce_emit_move_insn (if_info->x, target);
 
       seq = get_insns ();
+      unshare_ifcvt_sequence (if_info, seq);
       end_sequence ();
 
       if (seq_contains_jump (seq))
@@ -898,9 +955,11 @@ noce_try_addcc (struct noce_if_info *if_info)
 	{
 	  start_sequence ();
 	  target = emit_conditional_add (if_info->x, code,
-					 XEXP (cond, 0), XEXP (cond, 1),
+					 XEXP (cond, 0),
+					 XEXP (cond, 1),
 					 VOIDmode,
-					 if_info->b, XEXP (if_info->a, 1),
+					 if_info->b,
+					 XEXP (if_info->a, 1),
 					 GET_MODE (if_info->x),
 					 (code == LTU || code == GEU
 					  || code == LEU || code == GTU));
@@ -910,6 +969,7 @@ noce_try_addcc (struct noce_if_info *if_info)
 		noce_emit_move_insn (if_info->x, target);
 
 	      seq = get_insns ();
+	      unshare_ifcvt_sequence (if_info, seq);
 	      end_sequence ();
 	      emit_insn_before_setloc (seq, if_info->jump,
 				      INSN_LOCATOR (if_info->insn_a));
@@ -948,6 +1008,7 @@ noce_try_addcc (struct noce_if_info *if_info)
 		noce_emit_move_insn (if_info->x, target);
 
 	      seq = get_insns ();
+	      unshare_ifcvt_sequence (if_info, seq);
 	      end_sequence ();
 
 	      if (seq_contains_jump (seq))
@@ -991,7 +1052,8 @@ noce_try_store_flag_mask (struct noce_if_info *if_info)
 				     reversep, -1);
       if (target)
         target = expand_simple_binop (GET_MODE (if_info->x), AND,
-				      if_info->x, target, if_info->x, 0,
+				      if_info->x,
+				      target, if_info->x, 0,
 				      OPTAB_WIDEN);
 
       if (target)
@@ -1000,6 +1062,7 @@ noce_try_store_flag_mask (struct noce_if_info *if_info)
 	    noce_emit_move_insn (if_info->x, target);
 
 	  seq = get_insns ();
+	  unshare_ifcvt_sequence (if_info, seq);
 	  end_sequence ();
 
 	  if (seq_contains_jump (seq))
@@ -1097,6 +1160,7 @@ noce_try_cmove (struct noce_if_info *if_info)
 	    noce_emit_move_insn (if_info->x, target);
 
 	  seq = get_insns ();
+	  unshare_ifcvt_sequence (if_info, seq);
 	  end_sequence ();
 	  emit_insn_before_setloc (seq, if_info->jump,
 				  INSN_LOCATOR (if_info->insn_a));
@@ -1214,7 +1278,9 @@ noce_try_cmove_arith (struct noce_if_info *if_info)
       if (is_mem)
 	{
           tmp = gen_reg_rtx (GET_MODE (b));
-	  tmp = emit_insn (gen_rtx_SET (VOIDmode, tmp, b));
+	  tmp = emit_insn (gen_rtx_SET (VOIDmode,
+				  	tmp,
+					b));
 	}
       else if (! insn_b)
 	goto end_seq_and_fail;
@@ -1259,6 +1325,7 @@ noce_try_cmove_arith (struct noce_if_info *if_info)
     noce_emit_move_insn (x, target);
 
   tmp = get_insns ();
+  unshare_ifcvt_sequence (if_info, tmp);
   end_sequence ();
   emit_insn_before_setloc (tmp, if_info->jump, INSN_LOCATOR (if_info->insn_a));
   return TRUE;
@@ -1504,6 +1571,7 @@ noce_try_minmax (struct noce_if_info *if_info)
     noce_emit_move_insn (if_info->x, target);
 
   seq = get_insns ();
+  unshare_ifcvt_sequence (if_info, seq);
   end_sequence ();
 
   if (seq_contains_jump (seq))
@@ -1559,7 +1627,7 @@ noce_try_abs (struct noce_if_info *if_info)
     {
       rtx insn, note = NULL;
       for (insn = earliest;
-	   insn != if_info->test_bb->head;
+	   insn != BB_HEAD (if_info->test_bb);
 	   insn = PREV_INSN (insn))
 	if (INSN_P (insn)
 	    && ((note = find_reg_note (insn, REG_EQUAL, c))
@@ -1606,7 +1674,7 @@ noce_try_abs (struct noce_if_info *if_info)
 
   target = expand_abs_nojump (GET_MODE (if_info->x), b, if_info->x, 1);
 
-  /* ??? It's a quandry whether cmove would be better here, especially
+  /* ??? It's a quandary whether cmove would be better here, especially
      for integers.  Perhaps combine will clean things up.  */
   if (target && negate)
     target = expand_simple_unop (GET_MODE (target), NEG, target, if_info->x, 0);
@@ -1621,6 +1689,7 @@ noce_try_abs (struct noce_if_info *if_info)
     noce_emit_move_insn (if_info->x, target);
 
   seq = get_insns ();
+  unshare_ifcvt_sequence (if_info, seq);
   end_sequence ();
 
   if (seq_contains_jump (seq))
@@ -1758,7 +1827,7 @@ noce_process_if_block (struct ce_if_block * ce_info)
     }
 
   /* If this is not a standard conditional jump, we can't parse it.  */
-  jump = test_bb->end;
+  jump = BB_END (test_bb);
   cond = noce_get_condition (jump, &if_info.cond_earliest);
   if (! cond)
     return FALSE;
@@ -1874,8 +1943,8 @@ noce_process_if_block (struct ce_if_block * ce_info)
 	{
 	  rtx note;
 
-	  if (else_bb && insn_b == else_bb->end)
-	    else_bb->end = PREV_INSN (insn_b);
+	  if (else_bb && insn_b == BB_END (else_bb))
+	    BB_END (else_bb) = PREV_INSN (insn_b);
 	  reorder_insns (insn_b, insn_b, PREV_INSN (jump));
 
 	  /* If there was a REG_EQUAL note, delete it since it may have been
@@ -1894,6 +1963,27 @@ noce_process_if_block (struct ce_if_block * ce_info)
       goto success;
     }
 
+  /* Disallow the "if (...) x = a;" form (with an implicit "else x = x;")
+     for most optimizations if writing to x may trap, i.e. its a memory
+     other than a static var or a stack slot.  */
+  if (! set_b
+      && GET_CODE (orig_x) == MEM
+      && ! MEM_NOTRAP_P (orig_x)
+      && rtx_addr_can_trap_p (XEXP (orig_x, 0)))
+    {
+      if (HAVE_conditional_move)
+	{
+	  if (noce_try_cmove (&if_info))
+	    goto success;
+	  if (! HAVE_conditional_execution
+	      && noce_try_cmove_arith (&if_info))
+	    goto success;
+	}
+      return FALSE;
+    }
+
+  if (noce_try_move (&if_info))
+    goto success;
   if (noce_try_store_flag (&if_info))
     goto success;
   if (noce_try_minmax (&if_info))
@@ -1940,11 +2030,13 @@ noce_process_if_block (struct ce_if_block * ce_info)
   if (orig_x != x)
     {
       start_sequence ();
-      noce_emit_move_insn (copy_rtx (orig_x), x);
+      noce_emit_move_insn (orig_x, x);
       insn_b = get_insns ();
+      set_used_flags (orig_x);
+      unshare_all_rtl_in_chain (insn_b);
       end_sequence ();
 
-      emit_insn_after_setloc (insn_b, test_bb->end, INSN_LOCATOR (insn_a));
+      emit_insn_after_setloc (insn_b, BB_END (test_bb), INSN_LOCATOR (insn_a));
     }
 
   /* Merge the blocks!  */
@@ -2011,8 +2103,8 @@ merge_if_block (struct ce_if_block * ce_info)
 	{
 	  bb = fallthru;
 	  fallthru = block_fallthru (bb);
-	  if (post_dominators)
-	    delete_from_dominance_info (post_dominators, bb);
+	  if (dom_computed[CDI_POST_DOMINATORS] >= DOM_NO_FAST_QUERY)
+	    delete_from_dominance_info (CDI_POST_DOMINATORS, bb);
 	  merge_blocks (combo_bb, bb);
 	  num_true_changes++;
 	}
@@ -2028,8 +2120,8 @@ merge_if_block (struct ce_if_block * ce_info)
       if (combo_bb->global_live_at_end)
 	COPY_REG_SET (combo_bb->global_live_at_end,
 		      then_bb->global_live_at_end);
-      if (post_dominators)
-	delete_from_dominance_info (post_dominators, then_bb);
+      if (dom_computed[CDI_POST_DOMINATORS] >= DOM_NO_FAST_QUERY)
+	delete_from_dominance_info (CDI_POST_DOMINATORS, then_bb);
       merge_blocks (combo_bb, then_bb);
       num_true_changes++;
     }
@@ -2039,8 +2131,8 @@ merge_if_block (struct ce_if_block * ce_info)
      get their addresses taken.  */
   if (else_bb)
     {
-      if (post_dominators)
-	delete_from_dominance_info (post_dominators, else_bb);
+      if (dom_computed[CDI_POST_DOMINATORS] >= DOM_NO_FAST_QUERY)
+       	delete_from_dominance_info (CDI_POST_DOMINATORS, else_bb);
       merge_blocks (combo_bb, else_bb);
       num_true_changes++;
     }
@@ -2050,7 +2142,7 @@ merge_if_block (struct ce_if_block * ce_info)
 
   if (! join_bb)
     {
-      rtx last = combo_bb->end;
+      rtx last = BB_END (combo_bb);
 
       /* The outgoing edge for the current COMBO block should already
 	 be correct.  Verify this.  */
@@ -2096,8 +2188,8 @@ merge_if_block (struct ce_if_block * ce_info)
 	COPY_REG_SET (combo_bb->global_live_at_end,
 		      join_bb->global_live_at_end);
 
-      if (post_dominators)
-	delete_from_dominance_info (post_dominators, join_bb);
+      if (dom_computed[CDI_POST_DOMINATORS] >= DOM_NO_FAST_QUERY)
+	delete_from_dominance_info (CDI_POST_DOMINATORS, join_bb);
       merge_blocks (combo_bb, join_bb);
       num_true_changes++;
     }
@@ -2177,7 +2269,7 @@ find_if_header (basic_block test_bb, int pass)
       && find_cond_trap (test_bb, then_edge, else_edge))
     goto success;
 
-  if (post_dominators
+  if (dom_computed[CDI_POST_DOMINATORS] >= DOM_NO_FAST_QUERY
       && (! HAVE_conditional_execution || reload_completed))
     {
       if (find_if_case_1 (test_bb, then_edge, else_edge))
@@ -2241,8 +2333,8 @@ block_jumps_and_fallthru_p (basic_block cur_bb, basic_block target_bb)
      together for conditional execution support.  ??? we should support
      conditional execution support across calls for IA-64 some day, but
      for now it makes the code simpler.  */
-  end = cur_bb->end;
-  insn = cur_bb->head;
+  end = BB_END (cur_bb);
+  insn = BB_HEAD (cur_bb);
 
   while (insn != NULL_RTX)
     {
@@ -2373,7 +2465,7 @@ find_if_block (struct ce_if_block * ce_info)
   if (then_succ != NULL_EDGE
       && (then_succ->succ_next != NULL_EDGE
           || (then_succ->flags & EDGE_COMPLEX)
-	  || (flow2_completed && tablejump_p (then_bb->end, NULL, NULL))))
+	  || (flow2_completed && tablejump_p (BB_END (then_bb), NULL, NULL))))
     return FALSE;
 
   /* If the THEN block has no successors, conditional execution can still
@@ -2386,11 +2478,11 @@ find_if_block (struct ce_if_block * ce_info)
     {
       if (else_bb->pred->pred_next == NULL_EDGE)
 	{
-	  rtx last_insn = then_bb->end;
+	  rtx last_insn = BB_END (then_bb);
 
 	  while (last_insn
 		 && GET_CODE (last_insn) == NOTE
-		 && last_insn != then_bb->head)
+		 && last_insn != BB_HEAD (then_bb))
 	    last_insn = PREV_INSN (last_insn);
 
 	  if (last_insn
@@ -2421,7 +2513,7 @@ find_if_block (struct ce_if_block * ce_info)
 	   && else_bb->pred->pred_next == NULL_EDGE
 	   && else_succ->succ_next == NULL_EDGE
 	   && ! (else_succ->flags & EDGE_COMPLEX)
-	   && ! (flow2_completed && tablejump_p (else_bb->end, NULL, NULL)))
+	   && ! (flow2_completed && tablejump_p (BB_END (else_bb), NULL, NULL)))
     join_bb = else_succ->dest;
 
   /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination.  */
@@ -2435,15 +2527,15 @@ find_if_block (struct ce_if_block * ce_info)
       fprintf (rtl_dump_file, "\nIF-THEN%s block found, pass %d, start block %d [insn %d], then %d [%d]",
 	       (else_bb) ? "-ELSE" : "",
 	       ce_info->pass,
-	       test_bb->index, (test_bb->head) ? (int)INSN_UID (test_bb->head) : -1,
-	       then_bb->index, (then_bb->head) ? (int)INSN_UID (then_bb->head) : -1);
+	       test_bb->index, (BB_HEAD (test_bb)) ? (int)INSN_UID (BB_HEAD (test_bb)) : -1,
+	       then_bb->index, (BB_HEAD (then_bb)) ? (int)INSN_UID (BB_HEAD (then_bb)) : -1);
 
       if (else_bb)
 	fprintf (rtl_dump_file, ", else %d [%d]",
-		 else_bb->index, (else_bb->head) ? (int)INSN_UID (else_bb->head) : -1);
+		 else_bb->index, (BB_HEAD (else_bb)) ? (int)INSN_UID (BB_HEAD (else_bb)) : -1);
 
       fprintf (rtl_dump_file, ", join %d [%d]",
-	       join_bb->index, (join_bb->head) ? (int)INSN_UID (join_bb->head) : -1);
+	       join_bb->index, (BB_HEAD (join_bb)) ? (int)INSN_UID (BB_HEAD (join_bb)) : -1);
 
       if (ce_info->num_multiple_test_blocks > 0)
 	fprintf (rtl_dump_file, ", %d %s block%s last test %d [%d]",
@@ -2451,8 +2543,8 @@ find_if_block (struct ce_if_block * ce_info)
 		 (ce_info->and_and_p) ? "&&" : "||",
 		 (ce_info->num_multiple_test_blocks == 1) ? "" : "s",
 		 ce_info->last_test_bb->index,
-		 ((ce_info->last_test_bb->head)
-		  ? (int)INSN_UID (ce_info->last_test_bb->head)
+		 ((BB_HEAD (ce_info->last_test_bb))
+		  ? (int)INSN_UID (BB_HEAD (ce_info->last_test_bb))
 		  : -1));
 
       fputc ('\n', rtl_dump_file);
@@ -2513,7 +2605,7 @@ find_cond_trap (basic_block test_bb, edge then_edge, edge else_edge)
     }
 
   /* If this is not a standard conditional jump, we can't parse it.  */
-  jump = test_bb->end;
+  jump = BB_END (test_bb);
   cond = noce_get_condition (jump, &cond_earliest);
   if (! cond)
     return FALSE;
@@ -2537,7 +2629,8 @@ find_cond_trap (basic_block test_bb, edge then_edge, edge else_edge)
     }
 
   /* Attempt to generate the conditional trap.  */
-  seq = gen_cond_trap (code, XEXP (cond, 0), XEXP (cond, 1),
+  seq = gen_cond_trap (code, XEXP (cond, 0),
+		       XEXP (cond, 1),
 		       TRAP_CODE (PATTERN (trap)));
   if (seq == NULL)
     return FALSE;
@@ -2551,8 +2644,8 @@ find_cond_trap (basic_block test_bb, edge then_edge, edge else_edge)
   remove_edge (trap_bb == then_bb ? then_edge : else_edge);
   if (trap_bb->pred == NULL)
     {
-      if (post_dominators)
-	delete_from_dominance_info (post_dominators, trap_bb);
+      if (dom_computed[CDI_POST_DOMINATORS] >= DOM_NO_FAST_QUERY)
+	delete_from_dominance_info (CDI_POST_DOMINATORS, trap_bb);
       delete_block (trap_bb);
     }
 
@@ -2603,7 +2696,7 @@ block_has_only_trap (basic_block bb)
 
   /* The only instruction in the THEN block must be the trap.  */
   trap = first_active_insn (bb);
-  if (! (trap == bb->end
+  if (! (trap == BB_END (bb)
 	 && GET_CODE (PATTERN (trap)) == TRAP_IF
          && TRAP_CONDITION (PATTERN (trap)) == const_true_rtx))
     return NULL_RTX;
@@ -2736,8 +2829,8 @@ find_if_case_1 (basic_block test_bb, edge then_edge, edge else_edge)
 
   new_bb = redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb), else_bb);
   then_bb_index = then_bb->index;
-  if (post_dominators)
-    delete_from_dominance_info (post_dominators, then_bb);
+  if (dom_computed[CDI_POST_DOMINATORS] >= DOM_NO_FAST_QUERY)
+    delete_from_dominance_info (CDI_POST_DOMINATORS, then_bb);
   delete_block (then_bb);
 
   /* Make rest of code believe that the newly created block is the THEN_BB
@@ -2746,8 +2839,8 @@ find_if_case_1 (basic_block test_bb, edge then_edge, edge else_edge)
     {
       new_bb->index = then_bb_index;
       BASIC_BLOCK (then_bb_index) = new_bb;
-      if (post_dominators)
-	add_to_dominance_info (post_dominators, new_bb);
+      if (dom_computed[CDI_POST_DOMINATORS] >= DOM_NO_FAST_QUERY)
+	add_to_dominance_info (CDI_POST_DOMINATORS, new_bb);
     }
   /* We've possibly created jump to next insn, cleanup_cfg will solve that
      later.  */
@@ -2785,11 +2878,11 @@ find_if_case_2 (basic_block test_bb, edge then_edge, edge else_edge)
     return FALSE;
 
   /* ELSE is predicted or SUCC(ELSE) postdominates THEN.  */
-  note = find_reg_note (test_bb->end, REG_BR_PROB, NULL_RTX);
+  note = find_reg_note (BB_END (test_bb), REG_BR_PROB, NULL_RTX);
   if (note && INTVAL (XEXP (note, 0)) >= REG_BR_PROB_BASE / 2)
     ;
   else if (else_succ->dest->index < 0
-	   || dominated_by_p (post_dominators, then_bb,
+	   || dominated_by_p (CDI_POST_DOMINATORS, then_bb,
 			      else_succ->dest))
     ;
   else
@@ -2816,8 +2909,8 @@ find_if_case_2 (basic_block test_bb, edge then_edge, edge else_edge)
 		    then_bb->global_live_at_start,
 		    else_bb->global_live_at_end, BITMAP_IOR);
 
-  if (post_dominators)
-    delete_from_dominance_info (post_dominators, else_bb);
+  if (dom_computed[CDI_POST_DOMINATORS] >= DOM_NO_FAST_QUERY)
+    delete_from_dominance_info (CDI_POST_DOMINATORS, else_bb);
   delete_block (else_bb);
 
   num_true_changes++;
@@ -2852,11 +2945,11 @@ dead_or_predicable (basic_block test_bb, basic_block merge_bb,
 {
   rtx head, end, jump, earliest, old_dest, new_label = NULL_RTX;
 
-  jump = test_bb->end;
+  jump = BB_END (test_bb);
 
   /* Find the extent of the real code in the merge block.  */
-  head = merge_bb->head;
-  end = merge_bb->end;
+  head = BB_HEAD (merge_bb);
+  end = BB_END (merge_bb);
 
   if (GET_CODE (head) == CODE_LABEL)
     head = NEXT_INSN (head);
@@ -2886,8 +2979,8 @@ dead_or_predicable (basic_block test_bb, basic_block merge_bb,
   if (HAVE_conditional_execution)
     {
       /* In the conditional execution case, we have things easy.  We know
-	 the condition is reversible.  We don't have to check life info,
-	 becase we're going to conditionally execute the code anyway.
+	 the condition is reversible.  We don't have to check life info
+	 because we're going to conditionally execute the code anyway.
 	 All that's left is making sure the insns involved can actually
 	 be predicated.  */
 
@@ -3076,8 +3169,8 @@ dead_or_predicable (basic_block test_bb, basic_block merge_bb,
   /* Move the insns out of MERGE_BB to before the branch.  */
   if (head != NULL)
     {
-      if (end == merge_bb->end)
-	merge_bb->end = PREV_INSN (head);
+      if (end == BB_END (merge_bb))
+	BB_END (merge_bb) = PREV_INSN (head);
 
       if (squeeze_notes (&head, &end))
 	return TRUE;
@@ -3122,11 +3215,9 @@ if_convert (int x_life_data_ok)
   free_basic_block_vars (1);
 
   /* Compute postdominators if we think we'll use them.  */
-  post_dominators = NULL;
   if (HAVE_conditional_execution || life_data_ok)
-    {
-      post_dominators = calculate_dominance_info (CDI_POST_DOMINATORS);
-    }
+    calculate_dominance_info (CDI_POST_DOMINATORS);
+
   if (life_data_ok)
     clear_bb_flags ();
 
@@ -3163,8 +3254,7 @@ if_convert (int x_life_data_ok)
     fprintf (rtl_dump_file, "\n\n========== no more changes\n");
 #endif
 
-  if (post_dominators)
-    free_dominance_info (post_dominators);
+  free_dominance_info (CDI_POST_DOMINATORS);
 
   if (rtl_dump_file)
     fflush (rtl_dump_file);