> -----Original Message-----
> From: Andreas Schwab [mailto:[email protected]]
> Sent: 30 January 2014 14:29
> To: Paulo Matos
> Cc: [email protected]
> Subject: Re: Regression [v850,mep...]: sign_extend in loop breaks
> zero-overhead
> loop generation
>
> Paulo Matos <[email protected]> writes:
>
> > void
> > foo (short blockSize)
> > {
> > short i;
> > unsigned short loopCount;
> >
> > loopCount = (unsigned short) (blockSize + delayLength) % 8;
> > for (i = 0; i < loopCount; i++)
> > *temp_ptr++ = x ^ *temp_ptr++;
> > }
>
> You know that this is undefined code?
>
Correct, my apologies. I didn't notice the undefined behaviour that the reducer
introduced in the original code.
However, the issue persists.
If instead I write:
void
foo (short blockSize)
{
short i;
unsigned short loopCount;
loopCount = (unsigned short) (blockSize + delayLength) % 8;
for (i = 0; i < loopCount; i++)
*temp_ptr++ = x ^ *temp_ptr;
}
the sign extend is still generated from the referenced commit and persists
until trunk. This causes the zero overhead loop not to be generated.
Thanks,
Paulo Matos
> Andreas.
>
> --
> Andreas Schwab, [email protected]
> GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
> "And now for something completely different."
