PING^4 [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);
>>>> +}
>>>> +
>>>