tree-optimization/106781 - adjust cgraph lhs removal

The following matches up the cgraph code removing LHS of a noreturn
call with what fixup_noreturn_call does which gets along without
inserting a definition, fixing the ICE resulting from having no
place to actually insert that new def.

	PR tree-optimization/106781
	* cgraph.cc (cgraph_edge::redirect_call_stmt_to_callee): Copy
	LHS removal from fixup_noreturn_call.

	* gcc.dg/pr106781.c: New testcase.

diff --git a/gcc/cgraph.cc b/gcc/cgraph.cc
index 0417b05..5851b2f 100644 (file)
--- a/gcc/cgraph.cc
+++ b/gcc/cgraph.cc
@@ -1411,7 +1411,6 @@ cgraph_edge::redirect_call_stmt_to_callee (cgraph_edge *e)
 {
   tree decl = gimple_call_fndecl (e->call_stmt);
   gcall *new_stmt;
-  gimple_stmt_iterator gsi;
 
   if (e->speculative)
     {
@@ -1572,18 +1571,17 @@ cgraph_edge::redirect_call_stmt_to_callee (cgraph_edge *e)
       && (VOID_TYPE_P (TREE_TYPE (gimple_call_fntype (new_stmt)))
          || should_remove_lhs_p (lhs)))
     {
+      gimple_call_set_lhs (new_stmt, NULL_TREE);
+      /* We need to fix up the SSA name to avoid checking errors.  */
       if (TREE_CODE (lhs) == SSA_NAME)
        {
          tree var = create_tmp_reg_fn (DECL_STRUCT_FUNCTION (e->caller->decl),
                                        TREE_TYPE (lhs), NULL);
-         var = get_or_create_ssa_default_def
-                 (DECL_STRUCT_FUNCTION (e->caller->decl), var);
-         gimple *set_stmt = gimple_build_assign (lhs, var);
-         gsi = gsi_for_stmt (new_stmt);
-         gsi_insert_before_without_update (&gsi, set_stmt, GSI_SAME_STMT);
-         update_stmt_fn (DECL_STRUCT_FUNCTION (e->caller->decl), set_stmt);
+         SET_SSA_NAME_VAR_OR_IDENTIFIER (lhs, var);
+         SSA_NAME_DEF_STMT (lhs) = gimple_build_nop ();
+         set_ssa_default_def (DECL_STRUCT_FUNCTION (e->caller->decl),
+                              var, lhs);
        }
-      gimple_call_set_lhs (new_stmt, NULL_TREE);
       update_stmt_fn (DECL_STRUCT_FUNCTION (e->caller->decl), new_stmt);
     }
 

diff --git a/gcc/testsuite/gcc.dg/pr106781.c b/gcc/testsuite/gcc.dg/pr106781.c
new file mode 100644 (file)
index 0000000..339c28c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr106781.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wno-div-by-zero" } */
+
+int n;
+
+__attribute__ ((noinline, returns_twice)) static int
+bar (int)
+{
+  n /= 0;
+
+  return n;
+}
+
+int
+foo (int x)
+{
+  return bar (x);
+}