Re: [PATCH] Fix ifcvt (PR rtl-optimization/58668)

[Jakub Jelinek <jakub at redhat dot com>]

On Thu, Dec 19, 2013 at 12:38:49PM +0100, Steven Bosscher wrote:
> >> Why not use active_insn_p instead of hand-checks for USE and CLOBBER insns?
> >
> > Because it brings in the JUMP_TABLE_DATA mess into the picture?
> 
> Not as long as you look only between BB_HEAD and BB_END
> (JUMP_TABLE_DATA only appears outside basic blocks). AFAICT the code
> your patch touches only looks at insns contained in basic blocks.

So like this instead?  Bootstrapped/regtested on x86_64-linux and
i686-linux.  For 4.8 I'd still prefer the earlier patch though.

2013-12-18  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/58668
	* cfgcleanup.c (flow_find_cross_jump): Don't count
	any jumps if dir_p is NULL.  Remove p1 variable, use active_insn_p
	to determine what is counted.
	(flow_find_head_matching_sequence): Use active_insn_p to determine
	what is counted.
	(try_head_merge_bb): Adjust for the flow_find_head_matching_sequence
	counting change.
	* ifcvt.c (count_bb_insns): Use active_insn_p && !JUMP_P to
	determine what is counted.

	* gcc.dg/pr58668.c: New test.

--- gcc/ifcvt.c.jj	2013-12-19 16:20:32.849650410 +0100
+++ gcc/ifcvt.c	2013-12-19 17:28:28.544278601 +0100
@@ -118,7 +118,7 @@ count_bb_insns (const_basic_block bb)
 
   while (1)
     {
-      if (CALL_P (insn) || NONJUMP_INSN_P (insn))
+      if (active_insn_p (insn) && !JUMP_P (insn))
 	count++;
 
       if (insn == BB_END (bb))
--- gcc/cfgcleanup.c.jj	2013-12-19 09:03:05.600983104 +0100
+++ gcc/cfgcleanup.c	2013-12-19 17:27:20.808625980 +0100
@@ -1295,7 +1295,6 @@ flow_find_cross_jump (basic_block bb1, b
 {
   rtx i1, i2, last1, last2, afterlast1, afterlast2;
   int ninsns = 0;
-  rtx p1;
   enum replace_direction dir, last_dir, afterlast_dir;
   bool follow_fallthru, did_fallthru;
 
@@ -1323,8 +1322,9 @@ flow_find_cross_jump (basic_block bb1, b
       || (returnjump_p (i2) && !side_effects_p (PATTERN (i2))))
     {
       last2 = i2;
-      /* Count everything except for unconditional jump as insn.  */
-      if (!simplejump_p (i2) && !returnjump_p (i2) && last1)
+      /* Count everything except for unconditional jump as insn.
+	 Don't count any jumps if dir_p is NULL.  */
+      if (!simplejump_p (i2) && !returnjump_p (i2) && last1 && dir_p)
 	ninsns++;
       i2 = PREV_INSN (i2);
     }
@@ -1375,8 +1375,7 @@ flow_find_cross_jump (basic_block bb1, b
 	  last1 = i1, last2 = i2;
 	  afterlast_dir = last_dir;
 	  last_dir = dir;
-	  p1 = PATTERN (i1);
-	  if (!(GET_CODE (p1) == USE || GET_CODE (p1) == CLOBBER))
+	  if (active_insn_p (i1))
 	    ninsns++;
 	}
 
@@ -1494,7 +1493,8 @@ flow_find_head_matching_sequence (basic_
 
 	  beforelast1 = last1, beforelast2 = last2;
 	  last1 = i1, last2 = i2;
-	  ninsns++;
+	  if (active_insn_p (i1))
+	    ninsns++;
 	}
 
       if (i1 == BB_END (bb1) || i2 == BB_END (bb2)
@@ -2408,9 +2408,7 @@ try_head_merge_bb (basic_block bb)
       max_match--;
       if (max_match == 0)
 	return false;
-      do
-	e0_last_head = prev_real_insn (e0_last_head);
-      while (DEBUG_INSN_P (e0_last_head));
+      e0_last_head = prev_active_insn (e0_last_head);
     }
 
   if (max_match == 0)
@@ -2430,16 +2428,14 @@ try_head_merge_bb (basic_block bb)
       basic_block merge_bb = EDGE_SUCC (bb, ix)->dest;
       rtx head = BB_HEAD (merge_bb);
 
-      while (!NONDEBUG_INSN_P (head))
-	head = NEXT_INSN (head);
+      if (!active_insn_p (head))
+	head = next_active_insn (head);
       headptr[ix] = head;
       currptr[ix] = head;
 
       /* Compute the end point and live information  */
       for (j = 1; j < max_match; j++)
-	do
-	  head = NEXT_INSN (head);
-	while (!NONDEBUG_INSN_P (head));
+	head = next_active_insn (head);
       simulate_backwards_to_point (merge_bb, live, head);
       IOR_REG_SET (live_union, live);
     }
--- gcc/testsuite/gcc.dg/pr58668.c.jj	2013-12-19 17:24:13.239587709 +0100
+++ gcc/testsuite/gcc.dg/pr58668.c	2013-12-19 17:24:13.239587709 +0100
@@ -0,0 +1,25 @@
+/* PR rtl-optimization/58668 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+/* { dg-additional-options "-mthumb" { target { { arm*-*-* } && arm_thumb2_ok } } } */
+
+void *fn1 (void *);
+void *fn2 (void *, const char *);
+void fn3 (void *);
+void fn4 (void *, int);
+
+void *
+test (void *x)
+{
+  void *a, *b;
+  if (!(a = fn1 (x)))
+    return (void *) 0;
+  if (!(b = fn2 (a, "w")))
+    {
+      fn3 (a);
+      return (void *) 0;
+    }
+  fn3 (a);
+  fn4 (b, 1);
+  return b;
+}


	Jakub