[tree-ssa] Fix mudflap codegen and allow optimizations [patch]

[Frank Ch. Eigler]

Hi -

dnovillo wrote:
> The last mainline merge exposed a bug in mudflap's code
> generation.  [...]

Thanks for investigating this stuff and doing general cleanup.

> - The call to __builtin_expect was using BIT_IOR_EXPR instead of
>   TRUTH_ORIF_EXPR.  This prevents the short-circuit evaluation of
>   the predicate, producing slightly slower code. [...]

Are you sure about that?  Short-circuit evaluation usually requires
additional branches.  I recall experimenting with this early on, and
it made runs slower, not faster.


- FChE