[PATCH 4/6] Merge from stack branch: i386 backend changes

["Ye, Joey" <joey dot ye at intel dot com>]

OK to mainline?

Reviews:
http://gcc.gnu.org/ml/gcc-patches/2008-04/msg00349.html

2008-04-20  Joey Ye  <joey.ye@intel.com>
	    H.J. Lu  <hongjiu.lu@intel.com>
	    Xuepeng Guo <xuepeng.guo@intel.com>

	* config/i386/i386.c (ix86_force_align_arg_pointer_string):
Break
	long line.
	(ix86_user_incoming_stack_boundary): New.
	(ix86_default_incoming_stack_boundary): Likewise.
	(ix86_incoming_stack_boundary): Likewise.
	(find_drap_reg): Likewise.
	(ix86_finalize_stack_realign_flags): Likewise.
	(override_options): Overide option value for new options.
	(ix86_function_ok_for_sibcall): Sibcall is OK even stack need
	realigning.
	(ix86_handle_cconv_attribute): Stack realign no longer impacts
	number of regparm.
	(ix86_function_regparm): Likewise.
	(setup_incoming_varargs_64): Remove the logic to set
	stack_alignment_needed here.
	(ix86_va_start): Replace virtual_incoming_args_rtx with
	crtl->args.internal_arg_pointer.
	(ix86_save_reg): Replace force_align_arg_pointer with drap_reg.
	(ix86_compute_frame_layout): Compute frame layout wrt stack
	realignment.
	(ix86_internal_arg_pointer): Estimate if stack realignment is
	needed and returns appropriate arg pointer rtx accordingly.
	(ix86_expand_prologue): Finally decide if stack realignment
	is needed and generate prologue code accordingly.
	(ix86_expand_epilogue): Generate epilogue code wrt stack
	realignment is really needed or not.
	(ix86_select_alt_pic_regnum): Check DRAP register.
	
	* config/i386/i386.h (MAIN_STACK_BOUNDARY): New.
	(ABI_STACK_BOUNDARY): Likewise.
	PREFERRED_STACK_BOUNDARY_DEFAULT): Likewise.
	(STACK_REALIGN_DEFAULT): Likewise.
	(INCOMING_STACK_BOUNDARY): Likewise.
	(ix86_incoming_stack_boundary): Likewise.
	(MAX_VECTORIZE_STACK_ALIGNMENT): Define for i386.
	(REAL_PIC_OFFSET_TABLE_REGNUM): Updated to use BX_REG.
	(CAN_ELIMINATE): Redefine the macro to eliminate frame pointer
to
	stack pointer and arg pointer to hard frame pointer in case of
	stack realignment without DRAP.
	(machine_function): Remove force_align_arg_pointer.
	(ix86_incoming_stack_boundary): Declare new function.
	(force_align_arg_pointer): Removed.

	* config/i386/i386.md (BX_REG): New.
	(R13_REG): Likewise.

	* config/i386/i386.opt (mforce_drap): New.
	(mincoming-stack-boundary): Likewise.
	(mstackrealign): Updated.

Attachment: x86-0420.patch
Description: x86-0420.patch