From: Maxim Kuvyrkov <maxim@codesourcery.com>
Date: Tue, 27 Jul 2010 19:34:55 +0000 (+0000)
Subject: re PR rtl-optimization/40956 (Constants are never candidates for hoisting)
X-Git-Tag: releases/gcc-4.6.0~5386
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ce4c0015a16e1126844f5feaa57bcdf0aebdcb30;p=thirdparty%2Fgcc.git

re PR rtl-optimization/40956 (Constants are never candidates for hoisting)

	PR rtl-optimization/40956
	PR target/42495
	PR middle-end/42574
	* gcse.c (compute_code_hoist_vbeinout): Consider more expressions
	for hoisting.
	(hoist_code): Count occurences in current block too.

From-SVN: r162590
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0861109ab2d2..d39fbfca76f1 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2010-07-27  Maxim Kuvyrkov  <maxim@codesourcery.com>
+
+	PR rtl-optimization/40956
+	PR target/42495
+	PR middle-end/42574
+	* gcse.c (compute_code_hoist_vbeinout): Consider more expressions
+	for hoisting.
+	(hoist_code): Count occurences in current block too.
+
 2010-07-27  Maxim Kuvyrkov  <maxim@codesourcery.com>
 
 	* gcse.c (struct expr:max_distance): New field.
diff --git a/gcc/gcse.c b/gcc/gcse.c
index 9b44083fccd5..4b2547c33670 100644
--- a/gcc/gcse.c
+++ b/gcc/gcse.c
@@ -4247,8 +4247,15 @@ compute_code_hoist_vbeinout (void)
       FOR_EACH_BB_REVERSE (bb)
 	{
 	  if (bb->next_bb != EXIT_BLOCK_PTR)
-	    sbitmap_intersection_of_succs (hoist_vbeout[bb->index],
-					   hoist_vbein, bb->index);
+	    {
+	      sbitmap_intersection_of_succs (hoist_vbeout[bb->index],
+					     hoist_vbein, bb->index);
+
+	      /* Include expressions in VBEout that are calculated
+		 in BB and available at its end.  */
+	      sbitmap_a_or_b (hoist_vbeout[bb->index],
+			      hoist_vbeout[bb->index], comp[bb->index]);
+	    }
 
 	  changed |= sbitmap_a_or_b_and_c_cg (hoist_vbein[bb->index],
 					      antloc[bb->index],
@@ -4430,6 +4437,11 @@ hoist_code (void)
 
 	  if (TEST_BIT (hoist_vbeout[bb->index], i))
 	    {
+	      /* If an expression is computed in BB and is available at end of
+		 BB, hoist all occurences dominated by BB to BB.  */
+	      if (TEST_BIT (comp[bb->index], i))
+		hoistable++;
+
 	      /* We've found a potentially hoistable expression, now
 		 we look at every block BB dominates to see if it
 		 computes the expression.  */