Elimination of duplicate sign extensions

[Mark Shinwell]

Fu, Chao-Ying wrote:
>   I found new regressions for fixed-point tests on 9/20/2007,
> due to the missing of sign/zero extension.
> Please check the following code for __cmpuha2 in libgcc.
> The OLD CODE has zero extension, but the NEW CODE doesn't.
> This causes wrong comparison results.
> 
>   Any idea to fix this?  Is my libgcc code wrong?  Or should GCC
> sign/zero-extend "x" and "y" after memcpy?

Can you just confirm exactly which MIPS target and ABI this is
building for, and your exact compilation line?  I will investigate.

Thanks,
Mark