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Re: ifcvt: cond_exec-like behavior on cc0 machines


Hi Alex,

Alexandre Oliva wrote:
On Jul 17, 2003, Alexandre Oliva <aoliva@redhat.com> wrote:


I found out cond_exec can't contain cc0 in the condition, so I had to
change my plans in regards to implementing conditional bit-set and
bit-clear instructions on the port I'm working on.


rth asked me why on IRC, and asked me to post the details here, for
the list's benefit.

The reason is the init_propagate_block() block of code conditioned by
HAVE_conditional_execution.  Ports that use cc0 in conditions for
branches will crash here:

	  if (GET_CODE (reg) != REG)
	    abort ();

I remember this abort well it's triggered on D30v by the *bra_true pattern.

Graham





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