(gen_shl_and): Try to generate shorter constant for and.

From-SVN: r13101

diff --git a/gcc/config/sh/sh.c b/gcc/config/sh/sh.c
index cafbc5169ca21fcd7cbb8e19e7ab3b6233081014..c1bfc0e7476265f05bc8ea6771d35e7a32c8b549 100644 (file)
--- a/gcc/config/sh/sh.c
+++ b/gcc/config/sh/sh.c
@@ -1273,6 +1273,11 @@ gen_shl_and (dest, left_rtx, mask_rtx, source)
       shift_gen_fun = gen_shifty_op;
     case 2:
     case 3:
+      /* If the topmost bit that matters is set, set the topmost bits
+        that don't matter.  This way, we might be able to get a shorter
+        signed constant.  */
+      if (mask & ((HOST_WIDE_INT)1 << 31 - total_shift))
+       mask |= (HOST_WIDE_INT)~0 << (31 - total_shift);
       /* Don't expand fine-grained when combining, because that will
          make the pattern fail.  */
       if (rtx_equal_function_value_matters