Re: [PATCH] gimple.cc: Adjust gimple_call_builtin_p and gimple_call_combined_fn [PR105150]

[Jakub Jelinek via Gcc-patches]

On Wed, Apr 06, 2022 at 11:52:23AM +0200, Richard Biener wrote:
> On Wed, 6 Apr 2022, Jakub Jelinek wrote:
> 
> > On Wed, Apr 06, 2022 at 09:41:44AM +0100, Richard Sandiford wrote:
> > > But it seems like the magic incantation to detect “real” built-in
> > > function calls is getting longer and longer.  Can we not abstract this
> > > in a single place rather than have to repeat the same long sequence in
> > > multiple places?
> > 
> > I've already committed it, so it can be only dealt with an incremental
> > patch.
> > One possibility is to do it inside of
> > gimple_builtin_call_types_compatible_p, after the assert do that:
> >   if (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
> >     if (tree decl = builtin_decl_explicit (DECL_FUNCTION_CODE (fndecl)))
> >       fndecl = decl;
> > but we then lose the theoretical possibility of comparing against the
> > actual user declaration.  Though I guess in the
> > gimple-fold.cc
> > gimple-low.cc
> > gimple-match-head.cc
> > calls to that function we also want this rather than what they do currently.
> 
> Yes, I think it would be clearer to pass a BUILT_IN_* code to
> gimple_builtin_call_types_compatible_p and no decl and simply return
> false if we cannot get out hands at the "proper" decl from
> builtin_decl_explicit ...

That would mean we wouldn't verify the md or FE builtins anymore
and we would need to check for BUILT_IN_NORMAL in every caller (right now
we do that only in some of them).

Here is what I had in mind (untested so far):

2022-04-06  Jakub Jelinek  <ja...@redhat.com>

        PR tree-optimization/105150
        * gimple.cc (gimple_builtin_call_types_compatible_p): Use
        builtin_decl_explicit here...
        (gimple_call_builtin_p, gimple_call_combined_fn): ... rather than
        here.

--- gcc/gimple.cc.jj    2022-04-06 10:07:23.043064595 +0200
+++ gcc/gimple.cc       2022-04-06 11:31:31.704255242 +0200
@@ -2788,6 +2788,10 @@ gimple_builtin_call_types_compatible_p (
 {
   gcc_checking_assert (DECL_BUILT_IN_CLASS (fndecl) != NOT_BUILT_IN);
 
+  if (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
+    if (tree decl = builtin_decl_explicit (DECL_FUNCTION_CODE (fndecl)))
+      fndecl = decl;
+
   tree ret = gimple_call_lhs (stmt);
   if (ret
       && !useless_type_conversion_p (TREE_TYPE (ret),
@@ -2841,12 +2845,7 @@ gimple_call_builtin_p (const gimple *stm
   if (is_gimple_call (stmt)
       && (fndecl = gimple_call_fndecl (stmt)) != NULL_TREE
       && DECL_BUILT_IN_CLASS (fndecl) != NOT_BUILT_IN)
-    {
-      if (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
-       if (tree decl = builtin_decl_explicit (DECL_FUNCTION_CODE (fndecl)))
-         fndecl = decl;
-      return gimple_builtin_call_types_compatible_p (stmt, fndecl);
-    }
+    return gimple_builtin_call_types_compatible_p (stmt, fndecl);
   return false;
 }
 
@@ -2859,12 +2858,7 @@ gimple_call_builtin_p (const gimple *stm
   if (is_gimple_call (stmt)
       && (fndecl = gimple_call_fndecl (stmt)) != NULL_TREE
       && DECL_BUILT_IN_CLASS (fndecl) == klass)
-    {
-      if (klass == BUILT_IN_NORMAL)
-       if (tree decl = builtin_decl_explicit (DECL_FUNCTION_CODE (fndecl)))
-         fndecl = decl;
-      return gimple_builtin_call_types_compatible_p (stmt, fndecl);
-    }
+    return gimple_builtin_call_types_compatible_p (stmt, fndecl);
   return false;
 }
 
@@ -2877,11 +2871,7 @@ gimple_call_builtin_p (const gimple *stm
   if (is_gimple_call (stmt)
       && (fndecl = gimple_call_fndecl (stmt)) != NULL_TREE
       && fndecl_built_in_p (fndecl, code))
-    {
-      if (tree decl = builtin_decl_explicit (DECL_FUNCTION_CODE (fndecl)))
-       fndecl = decl;
-      return gimple_builtin_call_types_compatible_p (stmt, fndecl);
-    }
+    return gimple_builtin_call_types_compatible_p (stmt, fndecl);
   return false;
 }
 
@@ -2898,14 +2888,10 @@ gimple_call_combined_fn (const gimple *s
        return as_combined_fn (gimple_call_internal_fn (call));
 
       tree fndecl = gimple_call_fndecl (stmt);
-      if (fndecl && fndecl_built_in_p (fndecl, BUILT_IN_NORMAL))
-       {
-         tree decl = builtin_decl_explicit (DECL_FUNCTION_CODE (fndecl));
-         if (!decl)
-           decl = fndecl;
-         if (gimple_builtin_call_types_compatible_p (stmt, decl))
-           return as_combined_fn (DECL_FUNCTION_CODE (fndecl));
-       }
+      if (fndecl
+         && fndecl_built_in_p (fndecl, BUILT_IN_NORMAL)
+         && gimple_builtin_call_types_compatible_p (stmt, fndecl))
+       return as_combined_fn (DECL_FUNCTION_CODE (fndecl));
     }
   return CFN_LAST;
 }


        Jakub