re PR rtl-optimization/61222 (ICE on valid code at -O2 and -O3 on x86_64-linux-gnu in decompose, at rtl.h:1456)

gcc/
	PR rtl-optimization/61222
	* combine.c (simplify_shift_const_1): When moving a PLUS outside
	the shift, truncate the PLUS operand to the result mode.

gcc/testsuite/
	PR rtl-optimization/61222
	* gcc.c-torture/compile/pr61222-1.c: New test.
	* gcc.c-torture/compile/pr61222-2.c: Likewise.

From-SVN: r210945