tree-inline: Fix up __builtin_va_arg_pack handling [PR100898]

The following testcase ICEs, because gimple_call_arg_ptr (..., 0)
asserts that there is at least one argument, while we were using
it even if we didn't copy anything just to get a pointer from/to which
the zero arguments should be copied.

Fixed by guarding the memcpy calls.  Also, the code was calling
gimple_call_num_args too many times - 5 times instead of 2, so the patch
adds two temporaries for those.

2021-06-07  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/100898
	* tree-inline.c (copy_bb): Only use gimple_call_arg_ptr if memcpy
	should copy any arguments.  Don't call gimple_call_num_args
	on id->call_stmt or call_stmt more than once.

	* g++.dg/ext/va-arg-pack-3.C: New test.

(cherry picked from commit d66a703c8ba86f3ca04cc10c3071696e6d014de6)

diff --git a/gcc/testsuite/g++.dg/ext/va-arg-pack-3.C b/gcc/testsuite/g++.dg/ext/va-arg-pack-3.C
new file mode 100644 (file)
index 0000000..0e8203c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/va-arg-pack-3.C
@@ -0,0 +1,18 @@
+// PR middle-end/100898
+
+int a;
+int bar (int, ...);
+
+static inline __attribute__((always_inline)) int
+foo (...)
+{
+  while (a)
+    return bar (0, __builtin_va_arg_pack ());
+  return 0;
+}
+
+void
+baz (void)
+{
+  foo ();
+}

diff --git a/gcc/tree-inline.c b/gcc/tree-inline.c
index ac2ab14744a266491e71b15219be921306860c89..a24b10d04b81deeea611bb5a8c8c9c013cd7100d 100644 (file)
--- a/gcc/tree-inline.c
+++ b/gcc/tree-inline.c
@@ -2093,27 +2093,29 @@ copy_bb (copy_body_data *id, basic_block bb,
              tree p;
              gcall *new_call;
              vec<tree> argarray;
-             size_t nargs = gimple_call_num_args (id->call_stmt);
-             size_t n;
+             size_t nargs_caller = gimple_call_num_args (id->call_stmt);
+             size_t nargs = nargs_caller;
 
              for (p = DECL_ARGUMENTS (id->src_fn); p; p = DECL_CHAIN (p))
                nargs--;
 
              /* Create the new array of arguments.  */
-             n = nargs + gimple_call_num_args (call_stmt);
+             size_t nargs_callee = gimple_call_num_args (call_stmt);
+             size_t n = nargs + nargs_callee;
              argarray.create (n);
              argarray.safe_grow_cleared (n, true);
 
              /* Copy all the arguments before '...'  */
-             memcpy (argarray.address (),
-                     gimple_call_arg_ptr (call_stmt, 0),
-                     gimple_call_num_args (call_stmt) * sizeof (tree));
+             if (nargs_callee)
+               memcpy (argarray.address (),
+                       gimple_call_arg_ptr (call_stmt, 0),
+                       nargs_callee * sizeof (tree));
 
              /* Append the arguments passed in '...'  */
-             memcpy (argarray.address () + gimple_call_num_args (call_stmt),
-                     gimple_call_arg_ptr (id->call_stmt, 0)
-                     + (gimple_call_num_args (id->call_stmt) - nargs),
-                     nargs * sizeof (tree));
+             if (nargs)
+               memcpy (argarray.address () + nargs_callee,
+                       gimple_call_arg_ptr (id->call_stmt, 0)
+                       + (nargs_caller - nargs), nargs * sizeof (tree));
 
              new_call = gimple_build_call_vec (gimple_call_fn (call_stmt),
                                                argarray);