[patch] Do not generate useless branches for multi-word comparison

[Eric Botcazou]

Hi,

this improves the RTL generated for multi-word comparison to avoid generating 
useless branches.  In do_jump_by_parts_greater_rtx:
  1) do not generate the last cond jump,
  2) do not generate the uncond branch to the drop-through label, if any,
  3) generate only one comparison for the special (0 > x) case.

Tested on i586-suse-linux, OK for the mainline?


2011-03-24  Eric Botcazou  <ebotcazou@adacore.com>

	* dojump.c (do_jump_by_parts_greater_rtx): Optimize in specific cases.


-- 
Eric Botcazou
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