arm.h (arm_stack_offsets): Add locals_base field.

arm.h (arm_stack_offsets): Add locals_base field.

	* arm.h (arm_stack_offsets): Add locals_base field.
	* arm.c (arm_get_frame_offsets): Compute it.
	(thumb_compute_initial_elimination offset): Make the Thumb frame
	pointer point to the base of the local variables.
	(thumb_expand_prologue): Update accordingly.
	(thumb_expand_epilogue): Likewise.

	* arm.md (thumb_movhi_clobber): Make this insn a define_expand.  Change
	mode of clobbered scratch to DImode.  Handle a case that's known to
	need this.

From-SVN: r103301