PING^1 [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/595209.html

BR,
Kewen

on 2022/5/18 22:07, Kewen.Lin via Gcc-patches wrote:
> 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);
> +}
> +