On Tue, Apr 28, 2015 at 06:59:12PM +0200, Thomas Schwinge wrote:
> We're getting ready to submit patches extending the C/C++ front ends for
> the remaining OpenACC clauses, and given the current layout of
> gcc/c-family/c-pragma.h:pragma_omp_clause, we're then at 69 unique
> clauses, which is more than the 64-bit bitmask limit.
>
> > [...] I understand,
> > for example, PRAGMA_OMP_CLAUSE_REDUCTION to just be a "numeric
> > representation" of the "reduction" string [...]
>
> Should we now further split parsing of Cilk+/OpenACC/OpenMP pragmas (but
> I think you and I agreed that we don't want to go that route), or
> revisist Chung-Lin's std::bitset proposal (see below), or something else?
>
> Regarding std::bitset, you've been worried about performance,
> <http://news.gmane.org/find-root.php?message_id=%3C20141218142942.GM1667%40tucnak.redhat.com%3E>,
> but I'm not sure about this: aren't these code paths only exercised for
> pragma parsing, and aren't there really only ever one handful (or, a few)
> of pragmas per source code file, so this could hardly be an observable
> performance hit?
As I said earlier, I run into this during OpenMP 4.1 work too. The
std::bitset variant generates significantly larger code to what I've
bootstrapped/regtested on x86_64-linux and i686-linux and committed to
trunk. Furthermore, there are severe issues with including STL headers
in the middle of GCC include files, and not even C++14 allows bitsets to be
readably initialized (...set(X).set(Y).set(Z).set(W) doesn't IMHO count).
2015-04-29 Jakub Jelinek <ja...@redhat.com>
* c-common.h (omp_clause_mask): Unconditionally define as a class.
Use uint64_t instead of unsigned HOST_WIDE_INT and 64 instead of
HOST_BITS_PER_WIDE_INT.
--- gcc/c-family/c-common.h.jj 2015-04-11 15:55:57.000000000 +0200
+++ gcc/c-family/c-common.h 2015-04-29 10:19:17.629643284 +0200
@@ -1096,16 +1096,11 @@ extern void pp_dir_change (cpp_reader *,
extern bool check_missing_format_attribute (tree, tree);
/* In c-omp.c */
-#if HOST_BITS_PER_WIDE_INT >= 64
-typedef unsigned HOST_WIDE_INT omp_clause_mask;
-# define OMP_CLAUSE_MASK_1 ((omp_clause_mask) 1)
-#else
struct omp_clause_mask
{
inline omp_clause_mask ();
- inline omp_clause_mask (unsigned HOST_WIDE_INT l);
- inline omp_clause_mask (unsigned HOST_WIDE_INT l,
- unsigned HOST_WIDE_INT h);
+ inline omp_clause_mask (uint64_t l);
+ inline omp_clause_mask (uint64_t l, uint64_t h);
inline omp_clause_mask &operator &= (omp_clause_mask);
inline omp_clause_mask &operator |= (omp_clause_mask);
inline omp_clause_mask operator ~ () const;
@@ -1115,7 +1110,7 @@ struct omp_clause_mask
inline omp_clause_mask operator << (int);
inline bool operator == (omp_clause_mask) const;
inline bool operator != (omp_clause_mask) const;
- unsigned HOST_WIDE_INT low, high;
+ uint64_t low, high;
};
inline
@@ -1124,14 +1119,13 @@ omp_clause_mask::omp_clause_mask ()
}
inline
-omp_clause_mask::omp_clause_mask (unsigned HOST_WIDE_INT l)
+omp_clause_mask::omp_clause_mask (uint64_t l)
: low (l), high (0)
{
}
inline
-omp_clause_mask::omp_clause_mask (unsigned HOST_WIDE_INT l,
- unsigned HOST_WIDE_INT h)
+omp_clause_mask::omp_clause_mask (uint64_t l, uint64_t h)
: low (l), high (h)
{
}
@@ -1177,18 +1171,17 @@ inline omp_clause_mask
omp_clause_mask::operator << (int amount)
{
omp_clause_mask ret;
- if (amount >= HOST_BITS_PER_WIDE_INT)
+ if (amount >= 64)
{
ret.low = 0;
- ret.high = low << (amount - HOST_BITS_PER_WIDE_INT);
+ ret.high = low << (amount - 64);
}
else if (amount == 0)
ret = *this;
else
{
ret.low = low << amount;
- ret.high = (low >> (HOST_BITS_PER_WIDE_INT - amount))
- | (high << amount);
+ ret.high = (low >> (64 - amount)) | (high << amount);
}
return ret;
}
@@ -1197,17 +1190,16 @@ inline omp_clause_mask
omp_clause_mask::operator >> (int amount)
{
omp_clause_mask ret;
- if (amount >= HOST_BITS_PER_WIDE_INT)
+ if (amount >= 64)
{
- ret.low = high >> (amount - HOST_BITS_PER_WIDE_INT);
+ ret.low = high >> (amount - 64);
ret.high = 0;
}
else if (amount == 0)
ret = *this;
else
{
- ret.low = (high << (HOST_BITS_PER_WIDE_INT - amount))
- | (low >> amount);
+ ret.low = (high << (64 - amount)) | (low >> amount);
ret.high = high >> amount;
}
return ret;
@@ -1225,8 +1217,7 @@ omp_clause_mask::operator != (omp_clause
return low != b.low || high != b.high;
}
-# define OMP_CLAUSE_MASK_1 omp_clause_mask (1)
-#endif
+#define OMP_CLAUSE_MASK_1 omp_clause_mask (1)
enum c_omp_clause_split
{
Jakub
