* config/arm/arm.c (arm_compute_static_chain_stack_bytes): New
function.
(arm_compute_initial_elimination_offset): Use it.
(arm_compute_save_reg_mask): Include static chain save slot when
calculating alignment.
(arm_get_frame_offsets): Ditto.
(thumb1_compute_save_reg_mask): Ensure we have a low register saved
that we can use to decrement the stack when the stack decrement
could be too big for an immediate value in a single insn.
(thumb1_expand_prologue): Avoid using r12 for stack decrement.
From-SVN: r138327
