* combine.c (simplify_shift_const_1): Split code to determine
shift_mode into ...
(try_widen_shift_mode): ... here. Allow widening for ASHIFTRT if the
new bits shifted in are identical to the old sign bit.
testsuite/
* gcc.target/mips/octeon-exts-7.c: New test.
* gcc.target/mips/octeon-exts-2.c: Revert previous change.
* gcc.target/mips/octeon-exts-5.c: Likewise.
From-SVN: r149778
