(expand_divmod): When adjusting op0 for trunc_div or

trunc_mod, using shifts (not branches), make a new pseudo for the
result.  Don't use target for adjusted_op0.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@4081 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/expmed.c b/gcc/expmed.c
index 68f0607..90ab40f 100644 (file)
--- a/gcc/expmed.c
+++ b/gcc/expmed.c
@@ -2359,14 +2359,6 @@ expand_divmod (rem_flag, code, mode, op0, op1, target, unsignedp)
     case TRUNC_DIV_EXPR:
       if (log >= 0 && ! unsignedp)
        {
-         if (! can_clobber_op0)
-           {
-             adjusted_op0 = copy_to_suggested_reg (adjusted_op0, target,
-                                                   compute_mode);
-             /* Copy op0 to a reg, since emit_cmp_insn will call emit_queue
-                which will screw up mem refs for autoincrements.  */
-             op0 = force_reg (compute_mode, op0);
-           }
          /* Here we need to add OP1-1 if OP0 is negative, 0 otherwise.
             This can be computed without jumps by arithmetically shifting
             OP0 right LOG-1 places and then shifting right logically
@@ -2375,17 +2367,33 @@ expand_divmod (rem_flag, code, mode, op0, op1, target, unsignedp)
          if (log == 1 || BRANCH_COST >= 3)
            {
              rtx temp = gen_reg_rtx (compute_mode);
+             if (! can_clobber_op0)
+               /* Copy op0 to a reg, to play safe,
+                  since this is done in the other path.  */
+               op0 = force_reg (compute_mode, op0);
              temp = copy_to_suggested_reg (adjusted_op0, temp, compute_mode);
              temp = expand_shift (RSHIFT_EXPR, compute_mode, temp,
                                   build_int_2 (log - 1, 0), NULL_RTX, 0);
              temp = expand_shift (RSHIFT_EXPR, compute_mode, temp,
                                   build_int_2 (size - log, 0),
                                   temp, 1);
-             expand_inc (adjusted_op0, temp);
+             /* We supply 0 as the target to make a new pseudo
+                for the value; that helps loop.c optimize the result.  */
+             adjusted_op0 = expand_binop (compute_mode, add_optab,
+                                          adjusted_op0, temp,
+                                          0, 0, OPTAB_LIB_WIDEN);
            }
          else
            {
              rtx label = gen_label_rtx ();
+             if (! can_clobber_op0)
+               {
+                 adjusted_op0 = copy_to_suggested_reg (adjusted_op0, target,
+                                                       compute_mode);
+                 /* Copy op0 to a reg, since emit_cmp_insn will call emit_queue
+                    which will screw up mem refs for autoincrements.  */
+                 op0 = force_reg (compute_mode, op0);
+               }
              emit_cmp_insn (adjusted_op0, const0_rtx, GE, 
                             NULL_RTX, compute_mode, 0, 0);
              emit_jump_insn (gen_bge (label));