This patch improves the readability of the prolog and epilog code by moving some...

This patch improves the readability of the prolog and epilog code by moving some code into separate functions.

This patch improves the readability of the prolog and epilog code by moving
some code into separate functions.  There is no difference in generated code.

gcc/
	* config/aarch64/aarch64.c (aarch64_pushwb_pair_reg): Rename.
	(aarch64_push_reg): New function to push 1 or 2 registers.
	(aarch64_pop_reg): New function to pop 1 or 2 registers.
	(aarch64_expand_prologue): Use aarch64_push_regs.
	(aarch64_expand_epilogue): Use aarch64_pop_regs.

From-SVN: r238818