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Re: Unaligned double
- To: mklein at dis dot com (Mark Klein)
- Subject: Re: Unaligned double
- From: Joern Rennecke <amylaar at onetel dot net dot uk>
- Date: Mon, 22 Oct 2001 23:58:41 +0100 (BST)
- Cc: law at redhat dot com, gcc at gcc dot gnu dot org
> resolved. But, I'm not sure if that breaks anything else because
> I'm not sure why it was NO_REGS for pa32 and FP_REGS for pa64.
Changing CLASS_CANNOT_CHANGE_MODE from NO_REGS to a non-empty register class
should never cause the compiler to generate wrong code, unless something
else is broken. However, if needlessly defined, it can cause worse
code generation (i.e. larger & slower code) due to the restricted choices
of the register allocator. For targets with very tight register resources
(which the pa is not), it could also lead to reload aborts if it pushes
the maximum amount of registers of any class required for reload beyond
what is available.
So the main concern here would be the efficiency of the emitted code.
Joern Rennecke | gcc expert for hire
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