contrib/

[pf3gnuchains/gcc-fork.git] / gcc / dse.c

diff --git a/gcc/dse.c b/gcc/dse.c
index 9923326..0a3ebb4 100644 (file)
--- a/gcc/dse.c
+++ b/gcc/dse.c
@@ -1424,7 +1424,8 @@ static rtx
 find_shift_sequence (int access_size,
                     store_info_t store_info,
                     read_info_t read_info,
-                    int shift)
+                    int shift,
+                    bool speed)
 {
   enum machine_mode store_mode = GET_MODE (store_info->mem);
   enum machine_mode read_mode = GET_MODE (read_info->mem);
@@ -1444,7 +1445,7 @@ find_shift_sequence (int access_size,
        new_mode = GET_MODE_WIDER_MODE (new_mode))
     {
       rtx target, new_reg, shift_seq, insn, new_lhs;
-      int cost, offset;
+      int cost;
 
       /* Try a wider mode if truncating the store mode to NEW_MODE
         requires a real instruction.  */
@@ -1458,11 +1459,6 @@ find_shift_sequence (int access_size,
       if (!CONSTANT_P (store_info->rhs)
          && !MODES_TIEABLE_P (new_mode, store_mode))
        continue;
-      offset = subreg_lowpart_offset (new_mode, store_mode);
-      new_lhs = simplify_gen_subreg (new_mode, copy_rtx (store_info->rhs),
-                                    store_mode, offset);
-      if (new_lhs == NULL_RTX)
-       continue;
 
       new_reg = gen_reg_rtx (new_mode);
 
@@ -1483,7 +1479,7 @@ find_shift_sequence (int access_size,
       cost = 0;
       for (insn = shift_seq; insn != NULL_RTX; insn = NEXT_INSN (insn))
        if (INSN_P (insn))
-         cost += insn_rtx_cost (PATTERN (insn));
+         cost += insn_rtx_cost (PATTERN (insn), speed);
 
       /* The computation up to here is essentially independent
         of the arguments and could be precomputed.  It may
@@ -1495,6 +1491,11 @@ find_shift_sequence (int access_size,
       if (cost > COSTS_N_INSNS (1))
        continue;
 
+      new_lhs = extract_low_bits (new_mode, store_mode,
+                                 copy_rtx (store_info->rhs));
+      if (new_lhs == NULL_RTX)
+       continue;
+
       /* We found an acceptable shift.  Generate a move to
         take the value from the store and put it into the
         shift pseudo, then shift it, then generate another
@@ -1582,7 +1583,8 @@ replace_read (store_info_t store_info, insn_info_t store_insn,
             GET_MODE_NAME (store_mode), INSN_UID (store_insn->insn));
   start_sequence ();
   if (shift)
-    read_reg = find_shift_sequence (access_size, store_info, read_info, shift);
+    read_reg = find_shift_sequence (access_size, store_info, read_info, shift,
+                                   optimize_bb_for_speed_p (BLOCK_FOR_INSN (read_insn->insn)));
   else
     read_reg = extract_low_bits (read_mode, store_mode,
                                 copy_rtx (store_info->rhs));