From: hubicka <hubicka@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Fri, 4 Jun 2010 13:27:51 +0000 (+0000)
Subject: 	* dce.c (dce_process_block): Do not re-scan already marked instructions.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cbc39d5b2c70f1a1f882d7e0220f576fa1c01700;p=thirdparty%2Fgcc.git

	* dce.c (dce_process_block): Do not re-scan already marked instructions.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@160262 138bc75d-0d04-0410-961f-82ee72b054a4
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fa0304ffbd5e..9063edc4ee92 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2010-06-04  Jan Hubicka  <jh@suse.cz>
+
+	* dce.c (dce_process_block): Do not re-scan already marked instructions.
+
 2010-06-04  Bernd Schmidt  <bernds@codesourcery.com>
 
 	PR rtl-optimization/39871
diff --git a/gcc/dce.c b/gcc/dce.c
index 12f3af0760f2..7191f90414f5 100644
--- a/gcc/dce.c
+++ b/gcc/dce.c
@@ -904,19 +904,18 @@ dce_process_block (basic_block bb, bool redo_out, bitmap au)
   FOR_BB_INSNS_REVERSE (bb, insn)
     if (INSN_P (insn))
       {
-	bool needed = false;
+	bool needed = marked_insn_p (insn);
 
 	/* The insn is needed if there is someone who uses the output.  */
-	for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
-	  if (bitmap_bit_p (local_live, DF_REF_REGNO (*def_rec))
-	      || bitmap_bit_p (au, DF_REF_REGNO (*def_rec)))
-	    {
-	      needed = true;
-	      break;
-	    }
-
-	if (needed)
-	  mark_insn (insn, true);
+	if (!needed)
+	  for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
+	    if (bitmap_bit_p (local_live, DF_REF_REGNO (*def_rec))
+		|| bitmap_bit_p (au, DF_REF_REGNO (*def_rec)))
+	      {
+		needed = true;
+		mark_insn (insn, true);
+		break;
+	      }
 
 	/* No matter if the instruction is needed or not, we remove
 	   any regno in the defs from the live set.  */
@@ -924,7 +923,7 @@ dce_process_block (basic_block bb, bool redo_out, bitmap au)
 
 	/* On the other hand, we do not allow the dead uses to set
 	   anything in local_live.  */
-	if (marked_insn_p (insn))
+	if (needed)
 	  df_simulate_uses (insn, local_live);
       }