gccrs: Fix overflow intrinsic use before init

The overflow intrinsic returns a tuple of (value, boolean) where it value is the operator result and boolean if it overflowed or not. The intrinsic here did not initilize the resulting tuple and therefore was creating a use before init error resulting in garbage results Addresses Rust-GCC#1895 gcc/rust/ChangeLog: * backend/rust-compile-intrinsic.cc (op_with_overflow_inner): fix use before init Signed-off-by: Philip Herron <[email protected]>
CohenArthur · Jan 12, 2024 · 1bca174 · 1bca174
1 parent c2cf76e
commit 1bca174
Showing 1 changed file with 30 additions and 16 deletions.
diff --git a/gcc/rust/backend/rust-compile-intrinsic.cc b/gcc/rust/backend/rust-compile-intrinsic.cc
@@ -598,7 +598,25 @@ op_with_overflow_inner (Context *ctx, TyTy::FnType *fntype, tree_code op)
   if (!ctx->get_backend ()->function_set_parameters (fndecl, param_vars))
     return error_mark_node;
 
-  enter_intrinsic_block (ctx, fndecl);
+  rust_assert (fntype->get_num_substitutions () == 1);
+  auto &param_mapping = fntype->get_substs ().at (0);
+  const TyTy::ParamType *param_tyty = param_mapping.get_param_ty ();
+  TyTy::BaseType *resolved_tyty = param_tyty->resolve ();
+  tree template_parameter_type
+    = TyTyResolveCompile::compile (ctx, resolved_tyty);
+
+  // this should match y as well or we can take it from the TyTy structure
+  tree tmp_stmt = error_mark_node;
+  Bvariable *result_variable = ctx->get_backend ()->temporary_variable (
+    fndecl, NULL_TREE, template_parameter_type, NULL_TREE,
+    true /*address_is_taken*/, UNDEF_LOCATION, &tmp_stmt);
+  Bvariable *bool_variable
+    = ctx->get_backend ()->temporary_variable (fndecl, NULL_TREE,
+					       boolean_type_node, NULL_TREE,
+					       true /*address_is_taken*/,
+					       UNDEF_LOCATION, &tmp_stmt);
+
+  enter_intrinsic_block (ctx, fndecl, {result_variable, bool_variable});
 
   // BUILTIN op_with_overflow FN BODY BEGIN
   auto x = ctx->get_backend ()->var_expression (x_param, UNDEF_LOCATION);
@@ -628,24 +646,20 @@ op_with_overflow_inner (Context *ctx, TyTy::FnType *fntype, tree_code op)
     }
   rust_assert (overflow_builtin != error_mark_node);
 
-  // this should match y as well or we can take it from the TyTy structure
-  tree overflow_op_type = TREE_TYPE (x);
-  tree tmp_stmt = error_mark_node;
-  Bvariable *bvar
-    = ctx->get_backend ()->temporary_variable (fndecl, NULL_TREE,
-					       overflow_op_type, NULL_TREE,
-					       true /*address_is_taken*/,
-					       UNDEF_LOCATION, &tmp_stmt);
-  ctx->add_statement (tmp_stmt);
-
-  tree result_decl = bvar->get_tree (UNDEF_LOCATION);
+  tree bool_decl = bool_variable->get_tree (BUILTINS_LOCATION);
+  tree result_decl = result_variable->get_tree (BUILTINS_LOCATION);
   tree result_ref = build_fold_addr_expr_loc (BUILTINS_LOCATION, result_decl);
 
-  tree did_overflow_node
-    = build_call_expr_loc (BUILTINS_LOCATION, overflow_builtin, 3, x, y,
-			   result_ref);
+  tree builtin_call = build_call_expr_loc (BUILTINS_LOCATION, overflow_builtin,
+					   3, x, y, result_ref);
+
+  tree overflow_assignment
+    = ctx->get_backend ()->assignment_statement (bool_decl, builtin_call,
+						 BUILTINS_LOCATION);
+
+  ctx->add_statement (overflow_assignment);
 
-  std::vector<tree> vals = {result_decl, did_overflow_node};
+  std::vector<tree> vals = {result_decl, bool_decl};
   tree tuple_type = TREE_TYPE (DECL_RESULT (fndecl));
   tree result_expr
     = ctx->get_backend ()->constructor_expression (tuple_type, false, vals, -1,