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Re: Softfloat miscompiled by gcc 4.5.x

On Sun, Sep 30, 2012 at 11:13:20PM +0200, Martin Husemann wrote:
> Inspired by the tests done by SAITOH Masanobu, I narrowed down the -O2
> miscompilation a bit more. The attached patch uses -O1 for all softfloat
> source files, and keeps whatever other optimizations are used for the
> reminder of libc (and the whole base system).

I don't call that a fix.

There is either a bug in gcc (which will affect other code), or bugs
in the softfloat code itself - which will appear again later.
Also the performance of the softfloat code probably matters, and the
difference between -O2 and -O1 is probably measurable.

Shouldn't be too hard to isolate 1 buggy file and work out exactly
where it goes wrong.
I'd guess a 'strict aliasing' issue....


David Laight: david%l8s.co.uk@localhost

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