(expand_shift): Don't try extzv for lshr.

From-SVN: r7514

diff --git a/gcc/expmed.c b/gcc/expmed.c
index c0fe5f7..9abd372 100644 (file)
--- a/gcc/expmed.c
+++ b/gcc/expmed.c
@@ -1749,99 +1749,10 @@ expand_shift (code, mode, shifted, amount, target, unsignedp)
                               shifted, op1, target, unsignedp, methods1);
        }
 
-#ifdef HAVE_extzv
-      /* We can do a logical (unsigned) right shift with a bit-field
-        extract insn.  But first check if one of the above methods worked.  */
-      if (temp != 0)
-       return temp;
-
-      if (unsignedp && code == RSHIFT_EXPR && ! BITS_BIG_ENDIAN && HAVE_extzv)
-       {
-         enum machine_mode output_mode
-           = insn_operand_mode[(int) CODE_FOR_extzv][0];
-
-         if ((methods == OPTAB_DIRECT && mode == output_mode)
-             || (methods == OPTAB_WIDEN
-                 && GET_MODE_SIZE (mode) < GET_MODE_SIZE (output_mode)))
-           {
-             rtx shifted1 = convert_modes (output_mode, mode,
-                                           protect_from_queue (shifted, 0),
-                                           1);
-             enum machine_mode length_mode
-               = insn_operand_mode[(int) CODE_FOR_extzv][2];
-             enum machine_mode pos_mode
-               = insn_operand_mode[(int) CODE_FOR_extzv][3];
-             rtx target1 = 0;
-             rtx last = get_last_insn ();
-             rtx width;
-             rtx xop1 = op1;
-             rtx pat;
-
-             if (target != 0)
-               target1 = protect_from_queue (target, 1);
-
-             /* We define extract insns as having OUTPUT_MODE in a register
-                and the mode of operand 1 in memory.  Since we want
-                OUTPUT_MODE, we will always force the operand into a
-                register.  At some point we might want to support MEM
-                directly. */
-             shifted1 = force_reg (output_mode, shifted1);
-
-             /* If we don't have or cannot use a suggested target,
-                make a place for the result, in the proper mode.  */
-             if (methods == OPTAB_WIDEN || target1 == 0
-                 || ! ((*insn_operand_predicate[(int) CODE_FOR_extzv][0])
-                       (target1, output_mode)))
-               target1 = gen_reg_rtx (output_mode);
-
-             xop1 = protect_from_queue (xop1, 0);
-             xop1 = convert_modes (pos_mode, TYPE_MODE (TREE_TYPE (amount)),
-                                   xop1, TREE_UNSIGNED (TREE_TYPE (amount)));
-
-             /* If this machine's extzv insists on a register for
-                operand 3 (position), arrange for that.  */
-             if (! ((*insn_operand_predicate[(int) CODE_FOR_extzv][3])
-                    (xop1, pos_mode)))
-               xop1 = force_reg (pos_mode, xop1);
-
-             /* WIDTH gets the width of the bit field to extract:
-                wordsize minus # bits to shift by.  */
-             if (GET_CODE (xop1) == CONST_INT)
-               width = GEN_INT (GET_MODE_BITSIZE (mode) - INTVAL (op1));
-             else
-               {
-                 /* Now get the width in the proper mode.  */
-                 op1 = protect_from_queue (op1, 0);
-                 width = convert_to_mode (length_mode, op1,
-                                          TREE_UNSIGNED (TREE_TYPE (amount)));
-
-                 width = expand_binop (length_mode, sub_optab,
-                                       GEN_INT (GET_MODE_BITSIZE (mode)),
-                                       width, NULL_RTX, 0, OPTAB_LIB_WIDEN);
-               }
-
-             /* If this machine's extzv insists on a register for
-                operand 2 (length), arrange for that.  */
-             if (! ((*insn_operand_predicate[(int) CODE_FOR_extzv][2])
-                    (width, length_mode)))
-               width = force_reg (length_mode, width);
-
-             /* Now extract with WIDTH, omitting OP1 least sig bits.  */
-             pat = gen_extzv (target1, shifted1, width, xop1);
-             if (pat)
-               {
-                 emit_insn (pat);
-                 temp = convert_to_mode (mode, target1, 1);
-               }
-             else
-               delete_insns_since (last);
-           }
-
-         /* Can also do logical shift with signed bit-field extract
-            followed by inserting the bit-field at a different position.
-            That strategy is not yet implemented.  */
-       }
-#endif /* HAVE_extzv */
+      /* We used to try extzv here for logical right shifts, but that was
+        only useful for one machine, the VAX, and caused poor code 
+        generation there for lshrdi3, so the code was deleted and a
+        define_expand for lshrsi3 was added to vax.md.  */
     }
 
   if (temp == 0)