[Patch] PR rtl-optimization/71150, guard in_class_p check with REG_P

[Jiong Wang]

This bug is introduced by my commit r236181 where the inner rtx of
SUBREG haven't been checked while it should as "in_class_p" only
works with REG, and SUBREG_REG is actually not always REG.  If REG_P
check failed,  then we should fall back to normal code patch. The
following simple testcase for x86 can reproduce this bug.

long
foo (long a)
{
  return (unsigned) foo;
}

OK for trunk?

x86-64 bootstrap OK and no regression on check-gcc/g++.

2016-05-17  Jiong Wang  <jiong.w...@arm.com>

gcc/
  PR rtl-optimization/71150
  * lra-constraint (process_addr_reg): Guard "in_class_p" with REG_P check.


diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index 56ab5b4..e4e6c8c 100644
--- a/gcc/lra-constraints.c
+++ b/gcc/lra-constraints.c
@@ -1317,7 +1317,8 @@ process_addr_reg (rtx *loc, bool check_only_p, rtx_insn **before, rtx_insn **aft
 	 register, and this normally will be a subreg which should be reloaded
 	 as a whole.  This is particularly likely to be triggered when
 	 -fno-split-wide-types specified.  */
-      if (in_class_p (reg, cl, &new_class)
+      if (!REG_P (reg)
+	  || in_class_p (reg, cl, &new_class)
 	  || GET_MODE_SIZE (mode) <= GET_MODE_SIZE (ptr_mode))
        loc = &SUBREG_REG (*loc);
     }