| Message ID | 531B668D.8050301@net-b.de |
|---|---|
| State | New |
| Headers | show |
On Sat, Mar 08, 2014 at 07:50:53PM +0100, Tobias Burnus wrote: > OK for the trunk? > > diff --git a/libgfortran/libgfortran.h b/libgfortran/libgfortran.h > index d7e15ad..2664e1f 100644 > --- a/libgfortran/libgfortran.h > +++ b/libgfortran/libgfortran.h > @@ -97,6 +97,16 @@ typedef off_t gfc_offset; > #define NULL (void *) 0 > #endif > > + > +/* The following macros can be used to annotate conditions which are likely or > + unlikely to be true. Avoid using them when a condition is only slightly > + more likely/less unlikely than average to avoid the performance penalties of > + branch misprediction. In addition, as __builtin_expect overrides the compiler > + heuristic, do not use in conditions where one of the branches ends with a > + call to a function with __attributee__((noreturn)): the compiler internal s/__attributee/__attribute > + heuristic will mark this branch as much less likely as unlikely() would > + do. */ OK with the above change.
diff --git a/libgfortran/libgfortran.h b/libgfortran/libgfortran.h index d7e15ad..2664e1f 100644 --- a/libgfortran/libgfortran.h +++ b/libgfortran/libgfortran.h @@ -97,6 +97,16 @@ typedef off_t gfc_offset; #define NULL (void *) 0 #endif + +/* The following macros can be used to annotate conditions which are likely or + unlikely to be true. Avoid using them when a condition is only slightly + more likely/less unlikely than average to avoid the performance penalties of + branch misprediction. In addition, as __builtin_expect overrides the compiler + heuristic, do not use in conditions where one of the branches ends with a + call to a function with __attributee__((noreturn)): the compiler internal + heuristic will mark this branch as much less likely as unlikely() would + do. */ + #ifndef __GNUC__ #define __attribute__(x) #define likely(x) (x)