Richard Biener <richard.guent...@gmail.com> writes:
> On Mon, Nov 9, 2015 at 5:21 PM, Richard Sandiford
> <richard.sandif...@arm.com> wrote:
>> In practice all targets that can vectorise sqrt define the appropriate
>> sqrt<mode>2 optab. The only case where this isn't immediately obvious
>> is the libmass support in rs6000.c, but Mike Meissner said that it shouldn't
>> be exercised for sqrt.
>>
>> This patch therefore uses the internal function interface instead of
>> going via the target hook.
>>
>>
>> gcc/
>> * tree-vect-patterns.c: Include internal-fn.h.
>> (vect_recog_pow_pattern): Use IFN_SQRT instead of BUILT_IN_SQRT*.
>>
>> diff --git a/gcc/tree-vect-patterns.c b/gcc/tree-vect-patterns.c
>> index bab9a4f..a803e8c 100644
>> --- a/gcc/tree-vect-patterns.c
>> +++ b/gcc/tree-vect-patterns.c
>> @@ -39,6 +39,7 @@ along with GCC; see the file COPYING3. If not see
>> #include "tree-vectorizer.h"
>> #include "dumpfile.h"
>> #include "builtins.h"
>> +#include "internal-fn.h"
>> #include "case-cfn-macros.h"
>>
>> /* Pattern recognition functions */
>> @@ -1052,18 +1053,13 @@ vect_recog_pow_pattern (vec<gimple *> *stmts, tree
>> *type_in,
>> if (TREE_CODE (exp) == REAL_CST
>> && real_equal (&TREE_REAL_CST (exp), &dconsthalf))
>> {
>> - tree newfn = mathfn_built_in (TREE_TYPE (base), BUILT_IN_SQRT);
>> *type_in = get_vectype_for_scalar_type (TREE_TYPE (base));
>> - if (*type_in)
>> + if (*type_in && direct_internal_fn_supported_p (IFN_SQRT, *type_in))
>> {
>> - gcall *stmt = gimple_build_call (newfn, 1, base);
>> - if (vectorizable_function (stmt, *type_in, *type_in)
>> - != NULL_TREE)
>> - {
>> - var = vect_recog_temp_ssa_var (TREE_TYPE (base), stmt);
>> - gimple_call_set_lhs (stmt, var);
>> - return stmt;
>> - }
>> + gcall *stmt = gimple_build_call_internal (IFN_SQRT, 1, base);
>> + var = vect_recog_temp_ssa_var (TREE_TYPE (base), stmt);
>> + gimple_call_set_lhs (stmt, var);
>> + return stmt;
>
> Looks ok but I wonder if this is dead code with
>
> (for pows (POW)
> sqrts (SQRT)
> cbrts (CBRT)
> (simplify
> (pows @0 REAL_CST@1)
> (with {
> const REAL_VALUE_TYPE *value = TREE_REAL_CST_PTR (@1);
> REAL_VALUE_TYPE tmp;
> }
> (switch
> ...
> /* pow(x,0.5) -> sqrt(x). */
> (if (flag_unsafe_math_optimizations
> && canonicalize_math_p ()
> && real_equal (value, &dconsthalf))
> (sqrts @0))
Yeah, I wondered that too, although I think it's more likely to be dead
because of sincos. In the end it just seemed like a rabiit hole too far
though.
> Anyway, patch is ok.
Thanks,
Richard
