From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1005) id 732583858C52; Thu, 2 Feb 2023 19:13:23 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 732583858C52 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1675365203; bh=KZUOtiXZWhVkW/+MGlZSphifnqVJzjsheJ1fWNkWbK8=; h=From:To:Subject:Date:From; b=RvxmXDtwzMnxzZKHH0PwMzLLqIBH8uDOBgKxZF5eAQJJi5O5IhOfhDwsQGJGBrJ/6 lMYPMCXLs3MxAadSZw3v6vnP8p1HQo03E2ofXMZQezxK/DATVTrluEeqYlQUBDo9cG KE8vp11cmhZ/jPZC+l1eOOFV2LXLt0mTOW2nQ/eA= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Michael Meissner To: gcc-cvs@gcc.gnu.org Subject: [gcc(refs/users/meissner/heads/dmf008)] PR 108623: Bump up precision size to 16 bits. X-Act-Checkin: gcc X-Git-Author: Michael Meissner X-Git-Refname: refs/users/meissner/heads/dmf008 X-Git-Oldrev: 707b282b506abf96d27aa5ed84181f1f8ce53ace X-Git-Newrev: 7baf49088e307137b46e4c5a44ac06044f531372 Message-Id: <20230202191323.732583858C52@sourceware.org> Date: Thu, 2 Feb 2023 19:13:23 +0000 (GMT) List-Id: https://gcc.gnu.org/g:7baf49088e307137b46e4c5a44ac06044f531372 commit 7baf49088e307137b46e4c5a44ac06044f531372 Author: Michael Meissner Date: Thu Feb 2 14:12:59 2023 -0500 PR 108623: Bump up precision size to 16 bits. The new __dmr type that is being added as a possible future PowerPC instruction set bumps into a structure field size issue. The size of the __dmr type is 1024 bits. The precision field in tree_type_common is currently 10 bits, so if you store 1,024 into field, you get a 0 back. When you get 0 in the precision field, the ccp pass passes this 0 to sext_hwi in hwint.h. That function in turn generates a shift that is equal to the host wide int bit size, which is undefined as machine dependent for shifting in C/C++. int shift = HOST_BITS_PER_WIDE_INT - prec; return ((HOST_WIDE_INT) ((unsigned HOST_WIDE_INT) src << shift)) >> shift; It turns out the x86_64 where I first did my tests returns the original input before the two shifts, while the PowerPC always returns 0. In the ccp pass, the original input is -1, and so it worked. When I did the runs on the PowerPC, the result was 0, which ultimately led to the failure. In addition, once the precision field is larger, it will help PR C/102989 (C2x _BigInt) as well as the implementation of the SET_TYPE_VECTOR_SUBPARTS macro. I bootstraped various PowerPC compilers (power10 LE, power9 LE, power8 BE) along with an x86_64 build. There were no regressions. My proposed patches for the __dmr type now run fine. Can I install this into the master branch for GCC 13? 2023-02-02 Richard Biener Michael Meissner gcc/ PR middle-end/108623 PR C/102989 * hwint.h (sext_hwi): Add assertion against precision 0. * tree-core.h (tree_type_common): Bump up precision field to 16 bits. Align bit fields > 1 bit to at least an 8-bit boundary. Diff: --- gcc/hwint.h | 1 + gcc/tree-core.h | 24 ++++++++++++------------ 2 files changed, 13 insertions(+), 12 deletions(-) diff --git a/gcc/hwint.h b/gcc/hwint.h index e31aa006fa4..ba92efbfc25 100644 --- a/gcc/hwint.h +++ b/gcc/hwint.h @@ -277,6 +277,7 @@ ctz_or_zero (unsigned HOST_WIDE_INT x) static inline HOST_WIDE_INT sext_hwi (HOST_WIDE_INT src, unsigned int prec) { + gcc_checking_assert (prec != 0); if (prec == HOST_BITS_PER_WIDE_INT) return src; else diff --git a/gcc/tree-core.h b/gcc/tree-core.h index acd8deea34e..e5513208511 100644 --- a/gcc/tree-core.h +++ b/gcc/tree-core.h @@ -1686,18 +1686,8 @@ struct GTY(()) tree_type_common { tree attributes; unsigned int uid; - unsigned int precision : 10; - unsigned no_force_blk_flag : 1; - unsigned needs_constructing_flag : 1; - unsigned transparent_aggr_flag : 1; - unsigned restrict_flag : 1; - unsigned contains_placeholder_bits : 2; - + unsigned int precision : 16; ENUM_BITFIELD(machine_mode) mode : 8; - - /* TYPE_STRING_FLAG for INTEGER_TYPE and ARRAY_TYPE. - TYPE_CXX_ODR_P for RECORD_TYPE and UNION_TYPE. */ - unsigned string_flag : 1; unsigned lang_flag_0 : 1; unsigned lang_flag_1 : 1; unsigned lang_flag_2 : 1; @@ -1713,12 +1703,22 @@ struct GTY(()) tree_type_common { so we need to store the value 32 (not 31, as we need the zero as well), hence six bits. */ unsigned align : 6; + /* TYPE_STRING_FLAG for INTEGER_TYPE and ARRAY_TYPE. + TYPE_CXX_ODR_P for RECORD_TYPE and UNION_TYPE. */ + unsigned string_flag : 1; + unsigned no_force_blk_flag : 1; + unsigned warn_if_not_align : 6; + unsigned needs_constructing_flag : 1; + unsigned transparent_aggr_flag : 1; + + unsigned contains_placeholder_bits : 2; + unsigned restrict_flag : 1; unsigned typeless_storage : 1; unsigned empty_flag : 1; unsigned indivisible_p : 1; unsigned no_named_args_stdarg_p : 1; - unsigned spare : 15; + unsigned spare : 9; alias_set_type alias_set; tree pointer_to;