ifcvt.c (struct noce_if_info): Add then_else_reversed field.

	* ifcvt.c (struct noce_if_info): Add then_else_reversed field.
	(noce_get_alt_condition): Look at it to determine whether to
	reverse the condition or not.
	(noce_get_condition): Substitute the truth for lies.
	(noce_find_if_block): Set the then_else_reversed field.

From-SVN: r123327

gcc/ChangeLog

+2007-03-29  Steven Bosscher  <steven@gcc.gnu.org>
+
+	* ifcvt.c (struct noce_if_info): Add then_else_reversed field.
+	(noce_get_alt_condition): Look at it to determine whether to
+	reverse the condition or not.
+	(noce_get_condition): Substitute the truth for lies.
+	(noce_find_if_block): Set the then_else_reversed field.
+
 2007-03-29  Lars Poeschel <larsi@wh2.tu-dresden.de>
 
 	* config/fr30/fr30.md (movdi): Do not accept immediates as the

gcc/ifcvt.c

@@ -621,6 +621,12 @@ struct noce_if_info
 
   /* The SET_DEST of INSN_A.  */
   rtx x;
+
+  /* True if this if block is not canonical.  In the canonical form of
+     if blocks, the THEN_BB is the block reached via the fallthru edge
+     from TEST_BB.  For the noce transformations, we allow the symmetric
+     form as well.  */
+  bool then_else_reversed;
 };
 
 static rtx noce_emit_store_flag (struct noce_if_info *, rtx, int, int);
@@ -1503,6 +1509,8 @@ noce_get_alt_condition (struct noce_if_info *if_info, rtx target,
   reverse
     = GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
       && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (if_info->jump);
+  if (if_info->then_else_reversed)
+    reverse = !reverse;
 
   /* If we're looking for a constant, try to make the conditional
      have that constant in it.  There are two reasons why it may
@@ -2017,8 +2025,8 @@ noce_try_bitop (struct noce_if_info *if_info)
 /* Similar to get_condition, only the resulting condition must be
    valid at JUMP, instead of at EARLIEST.
 
-   If THEN_ELSE_REVERSED is true, the fallthrough goes to the THEN
-   block of the caller, and we have to reverse the condition.  */
+   If THEN_ELSE_REVERSED is true, the fallthrough does not go to the
+   THEN block of the caller, and we have to reverse the condition.  */
 
 static rtx
 noce_get_condition (rtx jump, rtx *earliest, bool then_else_reversed)
@@ -2036,8 +2044,9 @@ noce_get_condition (rtx jump, rtx *earliest, bool then_else_reversed)
   reverse = (GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
 	     && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (jump));
 
-  /* We may have to reverse because the caller's if block is not canonical
-     (i.e. the ELSE block isn't the fallthrough block for the TEST block).  */
+  /* We may have to reverse because the caller's if block is not canonical,
+     i.e. the THEN block isn't the fallthrough block for the TEST block
+     (see find_if_header).  */
   if (then_else_reversed)
     reverse = !reverse;
 
@@ -2735,6 +2744,7 @@ noce_find_if_block (basic_block test_bb,
   if_info.join_bb = join_bb;
   if_info.cond = cond;
   if_info.jump = jump;
+  if_info.then_else_reversed = then_else_reversed;
 
   /* Do the real work.  */