[gcc r12-8778] rs6000: Fix the check of bif argument number [PR104482]

[Kewen Lin <linkw@gcc.gnu.org>]

https://gcc.gnu.org/g:1a71881d05d3ec3e56492fff0197f88dcf4d9dbc

commit r12-8778-g1a71881d05d3ec3e56492fff0197f88dcf4d9dbc
Author: Kewen Lin <linkw@linux.ibm.com>
Date:   Tue Sep 13 04:14:23 2022 -0500

    rs6000: Fix the check of bif argument number [PR104482]
    
    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.
    
            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.
    
    (cherry picked from commit 38db48346cc045ed5656233c42d01d6d06bffc35)

Diff:
---
 gcc/config/rs6000/rs6000-c.cc               | 60 ++++++++++++++---------------
 gcc/testsuite/gcc.target/powerpc/pr104482.c | 16 ++++++++
 2 files changed, 46 insertions(+), 30 deletions(-)

diff --git a/gcc/config/rs6000/rs6000-c.cc b/gcc/config/rs6000/rs6000-c.cc
index 84bb98f94fb..fa0c93e1841 100644
--- a/gcc/config/rs6000/rs6000-c.cc
+++ b/gcc/config/rs6000/rs6000-c.cc
@@ -1755,6 +1755,36 @@ 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++)
@@ -1815,36 +1845,6 @@ 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);
+}
+