PING^2 [PATCH v3] rs6000: Fix the check of bif argument number [PR104482]

["Kewen.Lin" <linkw@linux.ibm.com>]

Hi,

Gentle ping https://gcc.gnu.org/pipermail/gcc-patches/2022-May/595208.html

BR,
Kewen

>> Hi,
>>
>> As PR104482 shown, it's one regression about the handlings when
>> the argument number is more than the one of built-in function
>> prototype.  The new bif support only catches the case that the
>> argument number is less than the one of function prototype, but
>> it misses the case that the argument number is more than the one
>> of function prototype.  Because it uses "n != expected_args",
>> n is updated in
>>
>>    for (n = 0; !VOID_TYPE_P (TREE_VALUE (fnargs)) && n < nargs;
>>         fnargs = TREE_CHAIN (fnargs), n++)
>>
>> , it's restricted to be less than or equal to expected_args with
>> the guard !VOID_TYPE_P (TREE_VALUE (fnargs)), so it's wrong.
>>
>> The fix is to use nargs instead, also move the checking hunk's
>> location ahead to avoid useless further scanning when the counts
>> mismatch.
>>
>> Bootstrapped and regtested on powerpc64-linux-gnu P8 and
>> powerpc64le-linux-gnu P9 and P10.
>>
>> v3: Update test case with dg-excess-errors.
>>
>> v2: Add one test case and refine commit logs.
>>     https://gcc.gnu.org/pipermail/gcc-patches/2022-April/593155.html
>>
>> v1: https://gcc.gnu.org/pipermail/gcc-patches/2022-March/591768.html
>>
>> Is it ok for trunk?
>>
>> BR,
>> Kewen
>> -----
>> 	PR target/104482
>>
>> gcc/ChangeLog:
>>
>> 	* config/rs6000/rs6000-c.cc (altivec_resolve_overloaded_builtin): Fix
>> 	the equality check for argument number, and move this hunk ahead.
>>
>> gcc/testsuite/ChangeLog:
>>
>> 	* gcc.target/powerpc/pr104482.c: New test.
>> ---
>>  gcc/config/rs6000/rs6000-c.cc               | 60 ++++++++++-----------
>>  gcc/testsuite/gcc.target/powerpc/pr104482.c | 16 ++++++
>>  2 files changed, 46 insertions(+), 30 deletions(-)
>>  create mode 100644 gcc/testsuite/gcc.target/powerpc/pr104482.c
>>
>> diff --git a/gcc/config/rs6000/rs6000-c.cc b/gcc/config/rs6000/rs6000-c.cc
>> index 9c8cbd7a66e..61881f29230 100644
>> --- a/gcc/config/rs6000/rs6000-c.cc
>> +++ b/gcc/config/rs6000/rs6000-c.cc
>> @@ -1756,6 +1756,36 @@ altivec_resolve_overloaded_builtin (location_t loc, tree fndecl,
>>    vec<tree, va_gc> *arglist = static_cast<vec<tree, va_gc> *> (passed_arglist);
>>    unsigned int nargs = vec_safe_length (arglist);
>>
>> +  /* If the number of arguments did not match the prototype, return NULL
>> +     and the generic code will issue the appropriate error message.  Skip
>> +     this test for functions where we don't fully describe all the possible
>> +     overload signatures in rs6000-overload.def (because they aren't relevant
>> +     to the expansion here).  If we don't, we get confusing error messages.  */
>> +  /* As an example, for vec_splats we have:
>> +
>> +; There are no actual builtins for vec_splats.  There is special handling for
>> +; this in altivec_resolve_overloaded_builtin in rs6000-c.cc, where the call
>> +; is replaced by a constructor.  The single overload here causes
>> +; __builtin_vec_splats to be registered with the front end so that can happen.
>> +[VEC_SPLATS, vec_splats, __builtin_vec_splats]
>> +  vsi __builtin_vec_splats (vsi);
>> +    ABS_V4SI SPLATS_FAKERY
>> +
>> +    So even though __builtin_vec_splats accepts all vector types, the
>> +    infrastructure cheats and just records one prototype.  We end up getting
>> +    an error message that refers to this specific prototype even when we
>> +    are handling a different argument type.  That is completely confusing
>> +    to the user, so it's best to let these cases be handled individually
>> +    in the resolve_vec_splats, etc., helper functions.  */
>> +
>> +  if (expected_args != nargs
>> +      && !(fcode == RS6000_OVLD_VEC_PROMOTE
>> +	   || fcode == RS6000_OVLD_VEC_SPLATS
>> +	   || fcode == RS6000_OVLD_VEC_EXTRACT
>> +	   || fcode == RS6000_OVLD_VEC_INSERT
>> +	   || fcode == RS6000_OVLD_VEC_STEP))
>> +    return NULL;
>> +
>>    for (n = 0;
>>         !VOID_TYPE_P (TREE_VALUE (fnargs)) && n < nargs;
>>         fnargs = TREE_CHAIN (fnargs), n++)
>> @@ -1816,36 +1846,6 @@ altivec_resolve_overloaded_builtin (location_t loc, tree fndecl,
>>        types[n] = type;
>>      }
>>
>> -  /* If the number of arguments did not match the prototype, return NULL
>> -     and the generic code will issue the appropriate error message.  Skip
>> -     this test for functions where we don't fully describe all the possible
>> -     overload signatures in rs6000-overload.def (because they aren't relevant
>> -     to the expansion here).  If we don't, we get confusing error messages.  */
>> -  /* As an example, for vec_splats we have:
>> -
>> -; There are no actual builtins for vec_splats.  There is special handling for
>> -; this in altivec_resolve_overloaded_builtin in rs6000-c.cc, where the call
>> -; is replaced by a constructor.  The single overload here causes
>> -; __builtin_vec_splats to be registered with the front end so that can happen.
>> -[VEC_SPLATS, vec_splats, __builtin_vec_splats]
>> -  vsi __builtin_vec_splats (vsi);
>> -    ABS_V4SI SPLATS_FAKERY
>> -
>> -    So even though __builtin_vec_splats accepts all vector types, the
>> -    infrastructure cheats and just records one prototype.  We end up getting
>> -    an error message that refers to this specific prototype even when we
>> -    are handling a different argument type.  That is completely confusing
>> -    to the user, so it's best to let these cases be handled individually
>> -    in the resolve_vec_splats, etc., helper functions.  */
>> -
>> -  if (n != expected_args
>> -      && !(fcode == RS6000_OVLD_VEC_PROMOTE
>> -	   || fcode == RS6000_OVLD_VEC_SPLATS
>> -	   || fcode == RS6000_OVLD_VEC_EXTRACT
>> -	   || fcode == RS6000_OVLD_VEC_INSERT
>> -	   || fcode == RS6000_OVLD_VEC_STEP))
>> -    return NULL;
>> -
>>    /* Some overloads require special handling.  */
>>    tree returned_expr = NULL;
>>    resolution res = unresolved;
>> diff --git a/gcc/testsuite/gcc.target/powerpc/pr104482.c b/gcc/testsuite/gcc.target/powerpc/pr104482.c
>> new file mode 100644
>> index 00000000000..92191265e4c
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/powerpc/pr104482.c
>> @@ -0,0 +1,16 @@
>> +/* { dg-require-effective-target powerpc_vsx_ok } */
>> +/* { dg-options "-mvsx" } */
>> +
>> +/* It's to verify no ICE here, ignore error messages about
>> +   mismatch argument number since they are not test points
>> +   here.  */
>> +/* { dg-excess-errors "pr104482" } */
>> +
>> +__attribute__ ((altivec (vector__))) int vsi;
>> +
>> +double
>> +testXXPERMDI (void)
>> +{
>> +  return __builtin_vsx_xxpermdi (vsi, vsi, 2, 4);
>> +}
>> +
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