Re: [PATCH] Be careful with MODE_CC in simplify_const_relational_operation.

2022-07-07 Thread Segher Boessenkool
Hi! On Thu, Jul 07, 2022 at 10:08:04PM +0100, Roger Sayle wrote: > I think it's fair to describe RTL's representation of condition flags > using MODE_CC as a little counter-intuitive. "A little challenging", and you should see that as a good thing, as a puzzle to crack :-) > For example, the i38

[PATCH] Be careful with MODE_CC in simplify_const_relational_operation.

2022-07-07 Thread Roger Sayle
I think it's fair to describe RTL's representation of condition flags using MODE_CC as a little counter-intuitive. For example, the i386 backend represents the carry flag (in adc instructions) using RTL of the form "(ltu:SI (reg:CCC) (const_int 0))", where great care needs to be taken not to trea