gcc/ * config/xtensa/xtensa-opts.h: New header. * config/xtensa/xtensa.h (STRICT_ALIGNMENT): Redefine as xtensa_strict_align. * config/xtensa/xtensa.cc (xtensa_option_override): When -m[no-]strict-align is not specified in the command line set xtensa_strict_align to 0 if the hardware supports both unaligned loads and stores or to 1 otherwise. * config/xtensa/xtensa.opt (mstrict-align): New option. * doc/invoke.texi (Xtensa Options): Document -m[no-]strict-align. --- gcc/config/xtensa/xtensa-opts.h | 28 ++++++++++++++++++++++++++++ gcc/config/xtensa/xtensa.cc | 4 ++++ gcc/config/xtensa/xtensa.h | 2 +- gcc/config/xtensa/xtensa.opt | 7 +++++++ gcc/doc/invoke.texi | 14 +++++++++++++- 5 files changed, 53 insertions(+), 2 deletions(-) create mode 100644 gcc/config/xtensa/xtensa-opts.h
diff --git a/gcc/config/xtensa/xtensa-opts.h b/gcc/config/xtensa/xtensa-opts.h new file mode 100644 index 000000000000..f0b8f5b3bfe7 --- /dev/null +++ b/gcc/config/xtensa/xtensa-opts.h @@ -0,0 +1,28 @@ +/* Definitions for option handling for Xtensa. + Copyright (C) 2023 Free Software Foundation, Inc. + +This file is part of GCC. + +GCC is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 3, or (at your option) +any later version. + +GCC is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GCC; see the file COPYING3. If not see +<http://www.gnu.org/licenses/>. */ + +#ifndef XTENSA_OPTS_H +#define XTENSA_OPTS_H + +/* Undefined state for the -mstrict-alignment option */ +enum xtensa_strict_alignment_setting { + XTENSA_STRICT_ALIGNMENT_UNDEFINED = -1, +}; + +#endif diff --git a/gcc/config/xtensa/xtensa.cc b/gcc/config/xtensa/xtensa.cc index 7287aa7a258a..9e5d314e143e 100644 --- a/gcc/config/xtensa/xtensa.cc +++ b/gcc/config/xtensa/xtensa.cc @@ -2792,6 +2792,10 @@ xtensa_option_override (void) if (xtensa_windowed_abi == -1) xtensa_windowed_abi = TARGET_WINDOWED_ABI_DEFAULT; + if (xtensa_strict_alignment == XTENSA_STRICT_ALIGNMENT_UNDEFINED) + xtensa_strict_alignment = !XCHAL_UNALIGNED_LOAD_HW + || !XCHAL_UNALIGNED_STORE_HW; + if (! TARGET_THREADPTR) targetm.have_tls = false; diff --git a/gcc/config/xtensa/xtensa.h b/gcc/config/xtensa/xtensa.h index 8ebf37cab33a..34e06afcff48 100644 --- a/gcc/config/xtensa/xtensa.h +++ b/gcc/config/xtensa/xtensa.h @@ -143,7 +143,7 @@ along with GCC; see the file COPYING3. If not see /* Set this nonzero if move instructions will actually fail to work when given unaligned data. */ -#define STRICT_ALIGNMENT 1 +#define STRICT_ALIGNMENT (xtensa_strict_alignment) /* Promote integer modes smaller than a word to SImode. Set UNSIGNEDP for QImode, because there is no 8-bit load from memory with sign diff --git a/gcc/config/xtensa/xtensa.opt b/gcc/config/xtensa/xtensa.opt index 3a129a4c0393..f16b53bf409f 100644 --- a/gcc/config/xtensa/xtensa.opt +++ b/gcc/config/xtensa/xtensa.opt @@ -18,6 +18,9 @@ ; along with GCC; see the file COPYING3. If not see ; <http://www.gnu.org/licenses/>. +HeaderInclude +config/xtensa/xtensa-opts.h + mconst16 Target Mask(CONST16) Use CONST16 instruction to load constants. @@ -64,3 +67,7 @@ Use call0 ABI. mabi=windowed Target RejectNegative Var(xtensa_windowed_abi, 1) Use windowed registers ABI. + +mstrict-align +Target Var(xtensa_strict_alignment) Init(XTENSA_STRICT_ALIGNMENT_UNDEFINED) +Do not use unaligned memory references. diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 57fb170ca4cc..54dcccbc148c 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -1474,7 +1474,8 @@ See RS/6000 and PowerPC Options. -mtarget-align -mno-target-align -mlongcalls -mno-longcalls -mabi=@var{abi-type} --mextra-l32r-costs=@var{cycles}} +-mextra-l32r-costs=@var{cycles} +-mstrict-align -mno-strict-align} @emph{zSeries Options} See S/390 and zSeries Options. @@ -34401,6 +34402,17 @@ instructions, in clock cycles. This affects, when optimizing for speed, whether loading a constant from literal pool using @code{L32R} or synthesizing the constant from a small one with a couple of arithmetic instructions. The default value is 0. + +@opindex mstrict-align +@opindex mno-strict-align +@item -mstrict-align +@itemx -mno-strict-align +Avoid or allow generating memory accesses that may not be aligned on a natural +object boundary as described in the architecture specification. +The default is @option{-mno-strict-align} for cores that support both +unaligned loads and stores in hardware and @option{-mstrict-align} for all +other cores. + @end table @node zSeries Options -- 2.30.2