Hi,

this patch rotates the loop generated in the prologue to do stack checking 
when -fstack-check is specified, thereby saving one branch instruction.  It 
was initially implemented as a WHILE loop to match the generic implementation 
but can be turned into a DO-WHILE loop because the amount of stack to be 
checked is known at compile time (since it's the static part of the frame).

The patch also fixes an error in the instruction count for the loop.

Tested on IA-64/Linux, OK for the mainline?


2015-11-12  Eric Botcazou  <ebotcazou@adacore.com>

	* config/ia64/ia64.c (ia64_emit_probe_stack_range): Adjust.
	(output_probe_stack_range): Rotate the loop and simplify.

-- 
Eric Botcazou