gimple.cc: Follow-up to adjust gimple_call_builtin_p and gimple_call_combined_fn [PR105150]

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.
Here is a patch that adjusts instead gimple_builtin_call_types_compatible_p,
after the assert:
  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.

2022-04-06  Jakub Jelinek  <jakub@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.

1 files changed, 11 insertions, 25 deletions

diff --git a/gcc/gimple.cc b/gcc/gimple.cc
index 4953bf4..9e62da4 100644
--- a/gcc/gimple.cc
+++ b/gcc/gimple.cc
@@ -2788,6 +2788,10 @@ gimple_builtin_call_types_compatible_p (const gimple *stmt, tree fndecl)
 {
   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 *stmt)
   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 *stmt, enum built_in_class klass)
   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 *stmt, enum built_in_function code)
   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 *stmt)
 	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;
 }