[PATCH][lower-subreg] Fix PR87507

[Eric Botcazou]

> 	PR rtl-optimization/87507
> 	* lower-subreg.c (operand_for_simple_move_operator): New function.
> 	(simple_move): Strip simple operators.
> 	(find_pseudo_copy): Likewise.
> 	(resolve_operand_for_simple_move_operator): New function.
> 	(resolve_simple_move): Strip simple operators and swap operands.
> 
> gcc/testsuite/
> 	PR rtl-optimization/87507
> 	* gcc.target/powerpc/pr87507.c: New test.
> 	* gcc.target/powerpc/pr68805.c: Update expected results.

OK with the s/simple/swap/ change suggested by Richard.

-- 
Eric Botcazou