Re: [PATCH] ARM half-precision floating point, 6/8 (really about part 2 now)

[Sandra Loosemore <sandra at codesourcery dot com>]

Paolo Bonzini wrote:
> Also, I came across the bug you fix in part 2 for my cond-optab work.
>
> > 2009-04-15  Sandra Loosemore  <sandra@codesourcery.com>
> >
> >     gcc/
> >     * optabs.c (prepare_float_lib_cmp):  Test that the comparison,
> >     swapped, and reversed optabs exist before trying to use them.
>
> This will actually be unnecessary after the cond-optab merge.  The bug
> here is that can_compare_p tries widening the operand and says "we can
> do UNLT by going through SFmode", so that UNLT is not split into
> UNORDERED and LT.  Then however prepare_cmp_insn does not try widening
> and prepare_float_lib_cmp crashes when it tries HFmode because UNLT does
> not have a libcall and hence an optab.  On the branch, widening is tried
> before libcalls, which works.
>
> If I beat you to committing the branch, I'll ask you to try reverting
> that part.  If (as it is likely) you're first, I'll test whether I can
> change this to an assert.

I got distracted before I could follow up on this, and now I see you've beaten 
me to it with the cond-optab merge.  I just re-tested and found that the fp16 
operations fall over in the cond-optab-merged version without my own optabs 
patch.  Do you have another not-yet-committed patch that is supposed to address 
this?  Otherwise I will just go ahead and commit mine, since it has already been 
approved.

-Sandra