flow patch for condexec

[Richard Henderson]

On Wed, Feb 21, 2001 at 03:44:37PM -0400, Aldy Hernandez wrote:
> ... so if-conversion might compare a and 5 on one ccr and a and 10 on
> another ccr ....  Now, if we have a chip in which comparisons between
> ccrs may yield undefined values...

One might ask why if-conversion would generate stuff that might yield
undefined values.

I havn't studdied this chip in detail, but as I understand things, the
situation is that if we avoid situations that might yield undefined
values, we can't do much at all.  So we have target-specific code do
some transformations, the result of which isn't quite representable
with the predication infrastructure that we had before Aldy's patch.

At least that's the basis on which I approved the patch...


r~