[Bug middle-end/42973] [4.5 regression] IRA apparently systematically making reload too busy on 2 address instructions with 3 operands

[hubicka at ucw dot cz]

------- Comment #3 from hubicka at ucw dot cz  2010-02-06 00:51 -------
Subject: Re:  [4.5 regression] IRA apparently
        systematically making reload too busy on 2 address instructions
        with 3 operands

> The argument for using conflicts is that the vast majority of the time if the
> constraints force us to tie a specific source to the destination, then the
> other source must not use the same hard reg as the destination.  There might be
> oddball cases where all the operands could share the same hard reg, but I
> suspect those would be extremely rare.

This should happen only when all operands are already same pseudo, and at that
time there won't be conflict to add, right?

Honza


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42973