2009-11-19 Paul Brook <paul@codesourcery.com>

[pf3gnuchains/gcc-fork.git] / gcc / df-scan.c

diff --git a/gcc/df-scan.c b/gcc/df-scan.c
index 45df29e..c12c00e 100644 (file)
--- a/gcc/df-scan.c
+++ b/gcc/df-scan.c
@@ -829,7 +829,8 @@ df_ref_create (rtx reg, rtx *loc, rtx insn,
   /* By adding the ref directly, df_insn_rescan my not find any
      differences even though the block will have changed.  So we need
      to mark the block dirty ourselves.  */  
-  df_set_bb_dirty (bb);
+  if (!DEBUG_INSN_P (DF_REF_INSN (ref)))
+    df_set_bb_dirty (bb);
 
   return ref;
 }
@@ -1027,7 +1028,8 @@ df_ref_remove (df_ref ref)
   /* By deleting the ref directly, df_insn_rescan my not find any
      differences even though the block will have changed.  So we need
      to mark the block dirty ourselves.  */  
-  df_set_bb_dirty (DF_REF_BB (ref));
+  if (!DEBUG_INSN_P (DF_REF_INSN (ref)))
+    df_set_bb_dirty (DF_REF_BB (ref));
   df_reg_chain_unlink (ref);
 }
 
@@ -3248,10 +3250,23 @@ df_uses_record (enum df_ref_class cl, struct df_collection_rec *collection_rec,
                    width = INTVAL (XEXP (dst, 1));
                    offset = INTVAL (XEXP (dst, 2));
                    mode = GET_MODE (dst);
-                   df_uses_record (DF_REF_EXTRACT, collection_rec, &XEXP (dst, 0), 
-                               DF_REF_REG_USE, bb, insn_info, 
-                               DF_REF_READ_WRITE | DF_REF_ZERO_EXTRACT, 
-                               width, offset, mode);
+                   if (GET_CODE (XEXP (dst,0)) == MEM)
+                     {
+                       /* Handle the case of zero_extract(mem(...)) in the set dest.
+                          This special case is allowed only if the mem is a single byte and 
+                          is useful to set a bitfield in memory.  */
+                       df_uses_record (DF_REF_EXTRACT, collection_rec, &XEXP (XEXP (dst,0), 0),
+                                       DF_REF_REG_MEM_STORE, bb, insn_info,
+                                       DF_REF_ZERO_EXTRACT,
+                                       width, offset, mode);
+                     }
+                   else
+                     {
+                       df_uses_record (DF_REF_EXTRACT, collection_rec, &XEXP (dst, 0), 
+                                       DF_REF_REG_USE, bb, insn_info, 
+                                       DF_REF_READ_WRITE | DF_REF_ZERO_EXTRACT, 
+                                       width, offset, mode);
+                     }
                  }
                else 
                  {