[branches/google/gcc-4_6] Backported r179661 and 179662 from mainline. (issue 5989043)

[asharif]

Reviewers: Diego Novillo, jingyu, davidxl,

Message:
Please take a look at this patch and tell me if it's OK for
branches/google/gcc-4_6.

Description:
Backported the following patch from trunk:

2011-10-07  Andrew Stubbs  <a...@codesourcery.com>

    gcc/
    * config/arm/predicates.md (shift_amount_operand): Remove constant
    range check.
    (shift_operator): Check range of constants for all shift operators.

    gcc/testsuite/
    * gcc.dg/pr50193-1.c: New file.
    * gcc.target/arm/shiftable.c: New file.


Please review this at http://codereview.appspot.com/5989043/

Affected files:
   M    .
  M     gcc/ChangeLog
  M     gcc/ChangeLog.google-4_6
  M     gcc/config/arm/predicates.md
  M     gcc/testsuite/ChangeLog
  A  +  gcc/testsuite/gcc.dg/pr50193-1.c
  A  +  gcc/testsuite/gcc.target/arm/shiftable.c