Commit Graph

249 Commits

Author SHA1 Message Date
Richard Henderson
ff0cc85ef3 tcg/aarch64: Rationalize args to tcg_out_qemu_{ld,st}
Rename the 'ext' parameter 'data_type' to make the use clearer;
pass it to tcg_out_qemu_st as well to even out the interfaces.
Rename the 'otype' local 'addr_type' to make the use clearer.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-05-05 17:20:01 +01:00
Richard Henderson
767c250310 tcg: Introduce tcg_out_xchg
We will want a backend interface for register swapping.
This is only properly defined for x86; all others get a
stub version that always indicates failure.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-04-23 08:46:45 +01:00
Richard Henderson
b3dfd5fc18 tcg: Introduce tcg_out_movext
This is common code in most qemu_{ld,st} slow paths, extending the
input value for the store helper data argument or extending the
return value from the load helper.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-04-23 08:46:45 +01:00
Richard Henderson
b8b94ac675 tcg: Split out tcg_out_extrl_i64_i32
We will need a backend interface for type truncation.  For those backends
that did not enable TCG_TARGET_HAS_extrl_i64_i32, use tcg_out_mov.
Use it in tcg_reg_alloc_op in the meantime.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-04-23 08:46:45 +01:00
Richard Henderson
b9bfe000f9 tcg: Split out tcg_out_extu_i32_i64
We will need a backend interface for type extension with zero.
Use it in tcg_reg_alloc_op in the meantime.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-04-23 08:46:45 +01:00
Richard Henderson
9c6aa274a4 tcg: Split out tcg_out_exts_i32_i64
We will need a backend interface for type extension with sign.
Use it in tcg_reg_alloc_op in the meantime.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-04-23 08:24:07 +01:00
Richard Henderson
9ecf5f61b8 tcg: Split out tcg_out_ext32u
We will need a backend interface for performing 32-bit zero-extend.
Use it in tcg_reg_alloc_op in the meantime.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-04-23 08:23:59 +01:00
Richard Henderson
52bf3398c3 tcg: Split out tcg_out_ext32s
We will need a backend interface for performing 32-bit sign-extend.
Use it in tcg_reg_alloc_op in the meantime.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-04-23 08:23:49 +01:00
Richard Henderson
379afdff47 tcg: Split out tcg_out_ext16u
We will need a backend interface for performing 16-bit zero-extend.
Use it in tcg_reg_alloc_op in the meantime.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-04-23 08:21:30 +01:00
Richard Henderson
753e42eada tcg: Split out tcg_out_ext16s
We will need a backend interface for performing 16-bit sign-extend.
Use it in tcg_reg_alloc_op in the meantime.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-04-23 08:21:19 +01:00
Richard Henderson
d0e66c897f tcg: Split out tcg_out_ext8u
We will need a backend interface for performing 8-bit zero-extend.
Use it in tcg_reg_alloc_op in the meantime.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-04-23 08:18:04 +01:00
Richard Henderson
678155b2c5 tcg: Split out tcg_out_ext8s
We will need a backend interface for performing 8-bit sign-extend.
Use it in tcg_reg_alloc_op in the meantime.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-04-23 08:17:49 +01:00
Richard Henderson
732e89f4c4 tcg: Replace tcg_abort with g_assert_not_reached
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-04-23 08:17:46 +01:00
Richard Henderson
a2495ede07 tcg/aarch64: Fix patching of LDR in tb_target_set_jmp_target
'offset' should be bits [23:5] of LDR instruction, rather than [4:0].

Fixes: d59d83a1c3 ("tcg/aarch64: Reorg goto_tb implementation")
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Reported-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-02-04 06:19:43 -10:00
Richard Henderson
5427a9a760 tcg: Add TCG_TARGET_CALL_{RET,ARG}_I128
Fill in the parameters for the host ABI for Int128 for
those backends which require no extra modification.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-02-04 06:19:42 -10:00
Richard Henderson
5e3d0c199f tcg: Introduce tcg_target_call_oarg_reg
Replace the flat array tcg_target_call_oarg_regs[] with
a function call including the TCGCallReturnKind.

Extend the set of registers for ARM to r0-r3 to match the ABI:
https://github.com/ARM-software/abi-aa/blob/main/aapcs32/aapcs32.rst#result-return

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-02-04 06:19:42 -10:00
Richard Henderson
6a6d772e30 tcg: Introduce tcg_out_addi_ptr
Implement the function for arm, i386, and s390x, which will use it.
Add stubs for all other backends.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-02-04 06:19:42 -10:00
Richard Henderson
d59d83a1c3 tcg/aarch64: Reorg goto_tb implementation
The old implementation replaces two insns, swapping between

	b	<dest>
	nop
	br	x30
and
	adrp	x30, <dest>
	addi	x30, x30, lo12:<dest>
	br	x30

There is a race condition in which a thread could be stopped at
the PC of the second insn, and when restarted does not see the
complete address computation and branches to nowhere.

The new implemetation replaces only one insn, swapping between

	b	<dest>
	br	tmp
and
	ldr	tmp, <jmp_addr>
	br	tmp

Reported-by: hev <r@hev.cc>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-17 10:36:02 -10:00
Richard Henderson
2fd2e78d1b tcg: Remove TCG_TARGET_HAS_direct_jump
We now have the option to generate direct or indirect
goto_tb depending on the dynamic displacement, thus
the define is no longer necessary or completely accurate.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-17 10:25:49 -10:00
Richard Henderson
0012e3516e tcg: Move tb_target_set_jmp_target declaration to tcg.h
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-17 10:22:35 -10:00
Richard Henderson
0fe1c98da9 tcg: Change tb_target_set_jmp_target arguments
Replace 'tc_ptr' and 'addr' with 'tb' and 'n'.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-17 10:21:54 -10:00
Richard Henderson
cf7d6b8e98 tcg: Split out tcg_out_goto_tb
The INDEX_op_goto_tb opcode needs no register allocation.
Split out a dedicated helper function for it.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-17 09:56:45 -10:00
Richard Henderson
b52a2c03b7 tcg: Introduce set_jmp_insn_offset
Similar to the existing set_jmp_reset_offset.  Move any assert for
TCG_TARGET_HAS_direct_jump into the new function (which now cannot
be build-time).  Will be unused if TCG_TARGET_HAS_direct_jump is
constant 0, but we can't test for constant in the preprocessor,
so just mark it G_GNUC_UNUSED.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-17 09:55:13 -10:00
Richard Henderson
7f83167c61 tcg: Replace asserts on tcg_jmp_insn_offset
Test TCG_TARGET_HAS_direct_jump instead of testing an
implementation pointer.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-17 09:55:13 -10:00
Richard Henderson
b55a8d9d0b tcg: Split out tcg_out_exit_tb
The INDEX_op_exit_tb opcode needs no register allocation.
Split out a dedicated helper function for it.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-17 09:55:13 -10:00
Richard Henderson
cee44b037b tcg: Add TCGHelperInfo argument to tcg_out_call
This eliminates an ifdef for TCI, and will be required for
expanding the call for TCGv_i128.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-05 11:41:29 -08:00
Richard Henderson
fa3cb9f9ff tcg/aarch64: Merge tcg_out_callr into tcg_out_call
There is only one use, and BLR is perhaps even more
self-documentary than CALLR.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-05 11:41:29 -08:00
Richard Henderson
eb8b0224fc tcg: Replace TCG_TARGET_EXTEND_ARGS with TCG_TARGET_CALL_ARG_I32
For 64-bit hosts that had TCG_TARGET_EXTEND_ARGS, set
TCG_TARGET_CALL_ARG_I32 to TCG_CALL_ARG_EXTEND.
Otherwise, use TCG_CALL_ARG_NORMAL.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-05 11:41:29 -08:00
Richard Henderson
c8eef96046 tcg: Replace TCG_TARGET_CALL_ALIGN_ARGS with TCG_TARGET_CALL_ARG_I64
For 32-bit hosts when TCG_TARGET_CALL_ALIGN_ARGS was set, use
TCG_CALL_ARG_EVEN.  For 64-bit hosts, TCG_TARGET_CALL_ALIGN_ARGS
was silently ignored, so always use TCG_CALL_ARG_NORMAL.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-05 11:41:29 -08:00
Richard Henderson
8d21de51b9 tcg: Remove TCG_TARGET_STACK_GROWSUP
The hppa host code has been removed since 2013; this
should have been deleted at the same time.

Fixes: 802b508123 ("tcg-hppa: Remove tcg backend")
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-04 16:20:01 -08:00
Qi Hu
122167659c tcg/aarch64: Remove unused code in tcg_out_op
AArch64 defines the TCG_TARGET_HAS_direct_jump. So the "else" block is
useless in the case of "INDEX_op_goto_tb" in function "tcg_out_op". Add
an assertion and delete these codes for clarity.

Suggested-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Qi Hu <huqi@loongson.cn>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20221017020826.990729-1-huqi@loongson.cn>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2022-10-25 22:01:14 +10:00
Richard Henderson
94bcc91b2e tcg/aarch64: Fix illegal insn from out-of-range shli
The masking in tcg_out_shl was incorrect, producing an
illegal instruction, rather than merely unspecified results
for the out-of-range shift.

Tested-by: Joel Stanley <joel@jms.id.au>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1051
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2022-06-02 08:09:46 -07:00
Marc-André Lureau
e03b56863d Replace config-time define HOST_WORDS_BIGENDIAN
Replace a config-time define with a compile time condition
define (compatible with clang and gcc) that must be declared prior to
its usage. This avoids having a global configure time define, but also
prevents from bad usage, if the config header wasn't included before.

This can help to make some code independent from qemu too.

gcc supports __BYTE_ORDER__ from about 4.6 and clang from 3.2.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
[ For the s390x parts I'm involved in ]
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220323155743.1585078-7-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-06 10:50:37 +02:00
Richard Henderson
7ceee3a19b tcg/aarch64: Use 'ull' suffix to force 64-bit constant
Typo used only 'ul' suffix, which is still 32-bits for windows host.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/947
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2022-03-31 11:03:59 -06:00
Richard Henderson
ed5234735a tcg: Add opcodes for vector nand, nor, eqv
We've had placeholders for these opcodes for a while,
and should have support on ppc, s390x and avx512 hosts.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2022-03-04 08:50:41 -10:00
Richard Henderson
f85ab3d2e5 tcg/aarch64: Support raising sigbus for user-only
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2022-02-09 08:55:02 +11:00
Frédéric Pétrot
fc313c6434 exec/memop: Adding signedness to quad definitions
Renaming defines for quad in their various forms so that their signedness is
now explicit.
Done using git grep as suggested by Philippe, with a bit of hand edition to
keep assignments aligned.

Signed-off-by: Frédéric Pétrot <frederic.petrot@univ-grenoble-alpes.fr>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20220106210108.138226-2-frederic.petrot@univ-grenoble-alpes.fr
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
2022-01-08 15:46:10 +10:00
Richard Henderson
9002ffcb72 tcg: Rename TCGMemOpIdx to MemOpIdx
We're about to move this out of tcg.h, so rename it
as we did when moving MemOp.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-10-05 16:53:17 -07:00
Richard Henderson
4b473e0c60 tcg: Expand MO_SIZE to 3 bits
We have lacked expressive support for memory sizes larger
than 64-bits for a while.  Fixing that requires adjustment
to several points where we used this for array indexing,
and two places that develop -Wswitch warnings after the change.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-10-05 16:53:17 -07:00
Richard Henderson
f4e01e3021 tcg: Remove TCG_TARGET_HAS_goto_ptr
Since 6eea04347e, all tcg backends support goto_ptr.
Remove the conditional, making support mandatory.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-07-09 20:23:38 -07:00
Richard Henderson
51c559c761 tcg/aarch64: Unset TCG_TARGET_HAS_MEMORY_BSWAP
The memory bswap support in the aarch64 backend merely dates from
a time when it was required.  There is nothing special about the
backend support that could not have been provided by the middle-end
even prior to the introduction of the bswap flags.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-06-29 10:04:57 -07:00
Richard Henderson
8fcfc6bff6 tcg/aarch64: Support bswap flags
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-06-29 10:04:57 -07:00
Richard Henderson
dfa24dfa09 tcg/aarch64: Merge tcg_out_rev{16,32,64}
Pass in the input and output size.  We currently use 3 of the 5
possible combinations; the others may be used by new tcg opcodes.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-06-29 10:04:57 -07:00
Richard Henderson
26a75d12d3 tcg: Move MAX_CODE_GEN_BUFFER_SIZE to tcg-target.h
Remove the ifdef ladder and move each define into the
appropriate header file.

Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-06-11 09:27:08 -07:00
Richard Henderson
a4fbbd779a tcg: Change parameters for tcg_target_const_match
Change the return value to bool, because that's what is should
have been from the start.  Pass the ct mask instead of the whole
TCGArgConstraint, as that's the only part that's relevant.

Change the value argument to int64_t.  We will need the extra
width for 32-bit hosts wanting to match vector constants.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-06-04 11:50:11 -07:00
Yasuo Kuwahara
26b1248f66 tcg/aarch64: Fix tcg_out_rotl
The last argument of tcg_out_extr() must be in the range 0-31 if ext==0.
Before the fix, when m==0 it becomes 32 and it crashes with an Illegal
instruction on Apple Silicon.  After the fix, it will be 0.  If m is in
the range 1-31, it is the same as before.

Signed-off-by: Yasuo Kuwahara <kwhr00@gmail.com>
Message-Id: <CAHfJ0vSXnmnTLmT0kR=a8ACRdw_UsLYOhStzUzgVEHoH8U-7sA@mail.gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-05-26 15:33:59 -07:00
Miroslav Rezanina
5e8892db93 tcg: Fix prototypes for tcg_out_vec_op and tcg_out_op
There are two different versions of prototype for tcg_out_op and
tcg_out_vec_op functions:

1) using const TCGArg *args and const int *const_args arguments
2) using const TCGArg args[TCG_MAX_OP_ARGS] and const int
   const_args[TCG_MAX_OP_ARGS] aguments.

This duality causes warnings on GCC 11 and prevents build using
--enable-werror.  As second version provides more information,
unify functions prototypes to this variant.

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
Message-Id: <20210312121418.139093-1-mrezanin@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-03-17 09:04:45 -06:00
Richard Henderson
d81bad24df tcg/aarch64: Fix generation of "scalar" vector operations
For some vector operations, "1D" is not a valid type, and there
are separate instructions for the 64-bit scalar operation.

Tested-by: Stefan Weil <sw@weilnetz.de>
Buglink: https://bugs.launchpad.net/qemu/+bug/1916112
Fixes: 14e4c1e235 ("tcg/aarch64: Add vector operations")
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-03-06 11:45:21 -08:00
Richard Henderson
6c2c7772f6 tcg/aarch64: Fix I3617_CMLE0
Fix a typo in the encodeing of the cmle (zero) instruction.

Fixes: 14e4c1e235 ("tcg/aarch64: Add vector operations")
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-03-06 11:45:21 -08:00
Richard Henderson
707b45a247 tcg/aarch64: Fix constant subtraction in tcg_out_addsub2
An hppa guest executing

0x000000000000e05c:  ldil L%10000,r4
0x000000000000e060:  ldo 0(r4),r4
0x000000000000e064:  sub r3,r4,sp

produces

 ---- 000000000000e064 000000000000e068
 sub2_i32 tmp0,tmp4,r3,$0x1,$0x10000,$0x0

after folding and constant propagation.  Then we hit

tcg-target.c.inc:640: tcg_out_insn_3401: Assertion `aimm <= 0xfff' failed.

because aimm is in fact -16, but unsigned.

The ((bl < 0) ^ sub) condition which negates bl is incorrect and will
always lead to this abort.  If the constant is positive, sub will make
it negative; if the constant is negative, sub will keep it negative.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-03-06 11:45:21 -08:00