[PATCH] Fix up sorting of block fragments (take 2)

[Jakub Jelinek]

On Mon, Aug 16, 2010 at 01:47:59PM -0700, Nathan Froyd wrote:
> On Mon, Aug 16, 2010 at 10:42:27PM +0200, Jakub Jelinek wrote:
> > 	* function.c (block_fragments_nreverse, blocks_nreverse_all): New
> > 	functions.
> > 	(reorder_blocks): Use blocks_nreverse_all instead of blocks_nreverse.
> > 	(reorder_blocks_1): Assert BLOCK_FRAGMENT_ORIGIN is NULL.  Don't
> > 	call block_nreverse here.
> > 
> > +/* Reverse the order of elements in the fragment chain T of blocks,
> > +   and return the new head of the chain (old last element).  */
> > +
> > +static tree
> > +block_fragments_nreverse (tree t)
> > +{
> > +  tree prev = 0, decl, next;
> 
> Can we use `block' instead of `decl' here and in blocks_nreverse_all?

Sure, good idea.  That decl in there came from blocks_nreverse, patch below
adjusts that function too.

2010-08-16  Jakub Jelinek  <jakub@redhat.com>

	* function.c (block_fragments_nreverse, blocks_nreverse_all): New
	functions.
	(reorder_blocks): Use blocks_nreverse_all instead of blocks_nreverse.
	(reorder_blocks_1): Assert BLOCK_FRAGMENT_ORIGIN is NULL.  Don't
	call block_nreverse here.
	(blocks_nreverse): Rename decl temporary to block.

--- gcc/function.c.jj	2010-02-26 16:58:08.000000000 +0100
+++ gcc/function.c	2010-03-21 17:41:29.000000000 +0100
@@ -3953,6 +3953,46 @@ generate_setjmp_warnings (void)
 }
 
 
+/* Reverse the order of elements in the fragment chain T of blocks,
+   and return the new head of the chain (old last element).  */
+
+static tree
+block_fragments_nreverse (tree t)
+{
+  tree prev = 0, block, next;
+  for (block = t; block; block = next)
+    {
+      next = BLOCK_FRAGMENT_CHAIN (block);
+      BLOCK_FRAGMENT_CHAIN (block) = prev;
+      prev = block;
+    }
+  return prev;
+}
+
+/* Reverse the order of elements in the chain T of blocks,
+   and return the new head of the chain (old last element).
+   Also do the same on subblocks and reverse the order of elements
+   in BLOCK_FRAGMENT_CHAIN as well.  */
+
+static tree
+blocks_nreverse_all (tree t)
+{
+  tree prev = 0, block, next;
+  for (block = t; block; block = next)
+    {
+      next = BLOCK_CHAIN (block);
+      BLOCK_CHAIN (block) = prev;
+      BLOCK_SUBBLOCKS (block) = blocks_nreverse_all (BLOCK_SUBBLOCKS (block));
+      if (BLOCK_FRAGMENT_CHAIN (block)
+	  && BLOCK_FRAGMENT_ORIGIN (block) == NULL_TREE)
+	BLOCK_FRAGMENT_CHAIN (block)
+	  = block_fragments_nreverse (BLOCK_FRAGMENT_CHAIN (block));
+      prev = block;
+    }
+  return prev;
+}
+
+
 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
    and create duplicate blocks.  */
 /* ??? Need an option to either create block fragments or to create
@@ -3979,7 +4019,7 @@ reorder_blocks (void)
 
   /* Recreate the block tree from the note nesting.  */
   reorder_blocks_1 (get_insns (), block, &block_stack);
-  BLOCK_SUBBLOCKS (block) = blocks_nreverse (BLOCK_SUBBLOCKS (block));
+  BLOCK_SUBBLOCKS (block) = blocks_nreverse_all (BLOCK_SUBBLOCKS (block));
 
   VEC_free (tree, heap, block_stack);
 }
@@ -4011,9 +4051,8 @@ reorder_blocks_1 (rtx insns, tree curren
 	      tree block = NOTE_BLOCK (insn);
 	      tree origin;
 
-	      origin = (BLOCK_FRAGMENT_ORIGIN (block)
-			? BLOCK_FRAGMENT_ORIGIN (block)
-			: block);
+	      gcc_assert (BLOCK_FRAGMENT_ORIGIN (block) == NULL_TREE);
+	      origin = block;
 
 	      /* If we have seen this block before, that means it now
 		 spans multiple address regions.  Create a new fragment.  */
@@ -4050,8 +4089,6 @@ reorder_blocks_1 (rtx insns, tree curren
 	  else if (NOTE_KIND (insn) == NOTE_INSN_BLOCK_END)
 	    {
 	      NOTE_BLOCK (insn) = VEC_pop (tree, *p_block_stack);
-	      BLOCK_SUBBLOCKS (current_block)
-		= blocks_nreverse (BLOCK_SUBBLOCKS (current_block));
 	      current_block = BLOCK_SUPERCONTEXT (current_block);
 	    }
 	}
@@ -4064,12 +4101,12 @@ reorder_blocks_1 (rtx insns, tree curren
 tree
 blocks_nreverse (tree t)
 {
-  tree prev = 0, decl, next;
-  for (decl = t; decl; decl = next)
+  tree prev = 0, block, next;
+  for (block = t; block; block = next)
     {
-      next = BLOCK_CHAIN (decl);
-      BLOCK_CHAIN (decl) = prev;
-      prev = decl;
+      next = BLOCK_CHAIN (block);
+      BLOCK_CHAIN (block) = prev;
+      prev = block;
     }
   return prev;
 }


	Jakub