https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64037
H.J. Lu <hjl.tools at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|Miscompilation with -Os and |[4.8/4.9/5 Regression]
|enum class : char parameter |Miscompilation with -Os and
| |enum class : char parameter
--- Comment #13 from H.J. Lu <hjl.tools at gmail dot com> ---
The bug was introduced by
https://gcc.gnu.org/ml/gcc-cvs/2007-09/msg00613.html
commit 5d93234932c3d8617ce92b77b7013ef6bede9508
Author: shinwell <shinwell@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Thu Sep 20 11:01:18 2007 +0000
gcc/
* combine.c: Include cgraph.h.
(setup_incoming_promotions): Rework to allow more aggressive
elimination of sign extensions when all call sites of the
current function are known to lie within the current unit.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@128618
138bc75d-0d04-0410-961f-82ee72b054a4
Before this commit, combine.c has
enum machine_mode mode = TYPE_MODE (TREE_TYPE (arg));
int uns = TYPE_UNSIGNED (TREE_TYPE (arg));
mode = promote_mode (TREE_TYPE (arg), mode, &uns, 1);
if (mode == GET_MODE (reg) && mode != DECL_MODE (arg))
{
rtx x;
x = gen_rtx_CLOBBER (DECL_MODE (arg), const0_rtx);
x = gen_rtx_fmt_e ((uns ? ZERO_EXTEND : SIGN_EXTEND), mode, x);
record_value_for_reg (reg, first, x);
}
It matches function.c:
/* This is not really promoting for a call. However we need to be
consistent with assign_parm_find_data_types and expand_expr_real_1. */
promoted_nominal_mode
= promote_mode (data->nominal_type, data->nominal_mode, &unsignedp, 1);
128618 changed
mode = promote_mode (TREE_TYPE (arg), mode, &uns, 1);
to
mode3 = promote_mode (DECL_ARG_TYPE (arg), mode2, &uns3, 1);
It breaks none WORD_REGISTER_OPERATIONS targets.
