PR target/10127
	PR ada/20548
	* expr.h (STACK_CHECK_PROBE_INTERVAL): Delete.
	(STACK_CHECK_PROBE_INTERVAL_EXP): New macro.
	(STACK_CHECK_MOVING_SP): Likewise.
	* system.h (STACK_CHECK_PROBE_INTERVAL): Poison it.
	* doc/tm.texi (Stack Checking): Delete STACK_CHECK_PROBE_INTERVAL.
	Document STACK_CHECK_PROBE_INTERVAL_EXP and STACK_CHECK_MOVING_SP.
	* doc/md.texi (Standard Pattern Names): Tweak entry of CHECK_STACK.
	Document PROBE_STACK.
	* explow.c (anti_adjust_stack_and_probe): New function.
	(allocate_dynamic_stack_space): Do not directly allocate space if
	STACK_CHECK_MOVING_SP, instead invoke above function.
	(emit_stack_probe): Handle probe_stack insn.
	(PROBE_INTERVAL): New macro.
	(STACK_GROW_OPTAB): Likewise.
	(STACK_GROW_OFF): Likewise.
	(probe_stack_range): Use Pmode and memory_address consistently.  Fix
	loop condition in the small constant case.  Rewrite in the general
	case to be immune to wraparounds.  Make sure the address of probes
	is valid.  Try to use [base + disp] addressing mode if possible.
	* ira.c (setup_eliminable_regset): Set frame_pointer_needed if stack
	checking is enabled and STACK_CHECK_MOVING_SP.
	* rtlanal.c (may_trap_p_1) <MEM>: If stack checking is enabled,
	return 1 for volatile references to the stack pointer.
	* tree.c (build_common_builtin_nodes): Do not set ECF_NOTHROW on
	__builtin_alloca if stack checking is enabled.
	* unwind-dw2.c (uw_identify_context): Take into account whether the
	context is that of a signal frame or not.
	* config/i386/linux.h (STACK_CHECK_MOVING_SP): Define to 1.
	* config/i386/linux64.h (STACK_CHECK_MOVING_SP): Likewise.

From-SVN: r153877