[committed] Use scalar_mode in expand_shift_1

[Richard Sandiford]

Since this function handles scalar and vector shifts:

  machine_mode scalar_mode = mode;
  if (VECTOR_MODE_P (mode))
    scalar_mode = GET_MODE_INNER (mode);

is equivalent to:

  scalar_mode = GET_MODE_INNER (mode);

Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64le-linux-gnu.
Applied as obvious.

Richard


2017-10-23  Richard Sandiford  <richard.sandif...@linaro.org>
            Alan Hayward  <alan.hayw...@arm.com>
            David Sherwood  <david.sherw...@arm.com>

gcc/
        * expmed.c (expand_shift_1): Use scalar_mode for scalar_mode.

Index: gcc/expmed.c
===================================================================
--- gcc/expmed.c        2017-09-23 10:27:39.925846365 +0100
+++ gcc/expmed.c        2017-10-23 10:30:47.246081163 +0100
@@ -2337,12 +2337,10 @@ expand_shift_1 (enum tree_code code, mac
   optab lrotate_optab = rotl_optab;
   optab rrotate_optab = rotr_optab;
   machine_mode op1_mode;
-  machine_mode scalar_mode = mode;
+  scalar_mode scalar_mode = GET_MODE_INNER (mode);
   int attempt;
   bool speed = optimize_insn_for_speed_p ();
 
-  if (VECTOR_MODE_P (mode))
-    scalar_mode = GET_MODE_INNER (mode);
   op1 = amount;
   op1_mode = GET_MODE (op1);