PPC64 Compiler bug !!

Anton Blanchard anton at samba.org
Sat Jun 14 08:02:54 EST 2003

> AIX does lazy floating point save/restore, though perhaps not in the
> same way as Linux.  So the behavior of a program (in AIX) that uses
> fprs for temp registers depends on the fp usage of other programs
> running on that CPU.

We do that on UP. On SMP the potential cost and complexity of sending
an IPI to unlazy the FPU when your process changes cpus is considered
too great to bother.

Anyway if AIX is using some form of lazy fp save/restore then it casts
the gcc optimisation into further doubt.


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