In memory operand addressing, which forms of displacement are permitted
besides Disp8 is pretty clearly limited
- outside of 64-bit mode, Disp16 or Disp32 only, depending on address
size (MPX being special in not allowing Disp16),
- in 64-bit mode, Disp32s or Disp64 without address size override, and
solely Disp32 with one.
Adjust assembler and i386-gen to match this, observing that templates
already get adjusted before trying to match them against input depending
on the presence of an address size prefix.
This adjustment logic gets extended to all cases, as certain DispNN
values should also be dropped when there's no such prefix. In fact
behavior of the assembler, perhaps besides the exact diagnostics wording,
should not differ between there being templates applicable to 64-bit and
non-64-bit at the same time, or there being fully separate sets of
templates, with their DispNN settings already reduced accordingly.
This adjustment logic further gets guarded such that there wouldn't be
and Disp<N> conversion based on address size prefix when this prefix
doesn't control the width of the displacement (on branches other than
absolute ones).
These adjustments then also allow folding two MOV templates, which had
been split between 64-bit and non-64-bits variants so far.
Once in this area also
- drop the bogus DispNN from JumpByte templates, leaving just the
correct Disp8 there (compensated by i386_finalize_displacement()
now setting Disp8 on their operands),
- add the missing Disp32S to XBEGIN.
Note that the changes make it necessary to temporarily mark a test as
XFAIL; this will get taken care of by a subsequent patch. The failing
parts are entirely bogus and will get replaced.
... instead of an operand one. Which operand it applies to can be
determined from other operand properties, but as it turns out the only
place it is actually used at doesn't even need further qualification.
EsSeg (a per-operand bit) is used with IsString (a per-insn attribute)
only. Extend the attribute to 2 bits, thus allowing to encode
- not a string insn,
- string insn with neither operand requiring use of %es:,
- string insn with 1st operand requiring use of %es:,
- string insn with 2nd operand requiring use of %es:,
which covers all possible cases, allowing to drop EsSeg.
The (transient) need to comment out the OTUnused #define did uncover an
oversight in the earlier OTMax -> OTNum conversion, which is being taken
care of here.
Drop the remaining instances left in place by commit c3949f432f ("x86:
limit ImmExt abuse), now that we have a way to specify specific GPRs.
Take the opportunity and also introduce proper 16-bit forms of
applicable SVME insns as well as 1-operand forms of CLZERO.
Special register "class" instances can't be combined with one another
(neither in templates nor in register entries), and hence it is not a
good use of resources (memory as well as execution time) to represent
them as individual bits of a bit field.
Furthermore the generalization becoming possible will allow
improvements to the handling of insns accepting only individual
registers as their operands.
Many operand types, in particular the various kinds of registers, can't
be combined with one another (neither in templates nor in register
entries), and hence it is not a good use of resources (memory as well as
execution time) to represent them as individual bits of a bit field.
Now that the opcode table gets preprocessed, undo parts of commit
dc821c5f9a ("x86: replace Reg8, Reg16, Reg32, and Reg64"): Have the
preprocessor handle the expansion there, while making the expansions
explicit in i386-gen and the register table.
The flag is used to indicate opcodes which can be switched between byte
and word/dword/qword forms (in a "canonical" way). Obviously it's quite
odd then to see it on insns not allowing for byte operands in the first
place. As a result the opcode bytes need to be adjusted accordingly,
which includes comparisons done in optimize_encoding().
To make re-introduction of such issues less likely have i386-gen
diagnose it (in a generally non-fatal way for now).
This was supposed to also be removed by c48dadc9a8 ('x86: drop "mem"
operand type attribute'). It's odd enough that this hasn't caused
build issues, considering the careful use of OTunused (apparently to
avoid "missing initializer" warnings).
To avoid such happening again introduce compile time consistency
checks.
... instead of an operand type bit: It's an insn property, not an
operand one. There's just one actual change to be made to the
templates: Most are now required to have the (unswapped) destination go
into ModR/M.rm, so VMOVD template needs its opcode adjusted accordingly
and its operands swapped. {,V}MOVS{S,D}, otoh, are left alone in this
regard, as otherwise generated code would differ from what we've been
producing so far (which I don't think is wanted).
Take the opportunity and add a missing IgnoreSize to pextrb (leading to
an error in 16-bit mode), and take the liberty to once again drop stray
IgnoreSize attributes from lines changed and neighboring related ones.
They're the only exception to there generally being no mix of register
kinds possible in an insn operand template, and there being two bits per
operand for their representation is also quite wasteful, considering the
low number of uses. Fold both bits and deal with the little bit of
fallout.
Also take the liberty and drop dead code trying to set REX_B: No segment
register has RegRex set on it.
Additionally I was quite surprised that PUSH/POP with the permitted
segment registers is not covered by the test cases. Add the missing
pieces.
It is pretty wasteful to have a per-operand flag which is used in
exactly 4 cases. It can be relatively easily replaced, and by doing so
I've actually found some dead code to remove at the same time (there's
no case of ImmExt set at the same time as Vec_Imm4).
For quite some time we've been using combinations of bits for
specifying various registers in operands and templates. I think it was
Alan who had indicated that likely the debug printing would need
adjustment as a result. Here we go.
Accumulator handling for GPRs gets changed to match that for FPU regs.
For this to work, OPERAND_TYPE_ACC{32,64} get repurposed, with their
original uses replaced by direct checks of the two bits of interest,
which is cheaper than operand_type_equal() invocations.
For SIMD registers nothing similar appears to be needed, as respective
operands get stripped from the (copy of the) template before pt() is
reached.
The type change on pi() is to silence a compiler diagnostic. Arguably
its other parameter could also be const-qualified.
There are separate CPUID feature bits for fxsave/fxrstor and cmovCC
instructions. This patch adds CpuCMOV and CpuFXSR to replace Cpu686
on corresponding instructions.
gas/
* config/tc-i386.c (cpu_arch): Add .cmov and .fxsr.
(cpu_noarch): Add nocmov and nofxsr.
* doc/c-i386.texi: Document cmov and fxsr.
opcodes/
* i386-gen.c (cpu_flag_init): Add CpuCMOV and CpuFXSR to
CPU_I686_FLAGS. Add CPU_CMOV_FLAGS, CPU_FXSR_FLAGS,
CPU_ANY_CMOV_FLAGS and CPU_ANY_FXSR_FLAGS.
(cpu_flags): Add CpuCMOV and CpuFXSR.
* i386-opc.tbl: Replace Cpu686 with CpuFXSR on fxsave, fxsave64,
fxrstor and fxrstor64. Replace Cpu686 with CpuCMOV on cmovCC.
* i386-init.h: Regenerated.
* i386-tbl.h: Likewise.
Expand Broadcast to 3 bits so that the number of bytes to broadcast
can be computed as 1 << (Broadcast - 1). Use it to simplify x86
assembler.
gas/
* config/tc-i386.c (Broadcast_Operation): Add bytes.
(build_evex_prefix): Use i.broadcast->bytes.
(match_broadcast_size): New function.
(check_VecOperands): Use the broadcast field to compute the
number of bytes to broadcast directly. Set i.broadcast->bytes.
Use match_broadcast_size.
opcodes/
* i386-gen.c (adjust_broadcast_modifier): New function.
(process_i386_opcode_modifier): Add an argument for operands.
Adjust the Broadcast value based on operands.
(output_i386_opcode): Pass operand_types to
process_i386_opcode_modifier.
(process_i386_opcodes): Pass NULL as operands to
process_i386_opcode_modifier.
* i386-opc.h (BYTE_BROADCAST): New.
(WORD_BROADCAST): Likewise.
(DWORD_BROADCAST): Likewise.
(QWORD_BROADCAST): Likewise.
(i386_opcode_modifier): Expand broadcast to 3 bits.
* i386-tbl.h: Regenerated.
Instead of expanding macro-like constructs in i386-gen, have the C pre-
processor do this for us. Besides being a prerequisite for the next
template folding steps, this also paves the way for removing various
hidden dependencies between #define-s in i386-opc.h and plain literal
numbers used in i386-opc.tbl.
The #undef of None is solely to leave the generated i386-tbl.h entirely
unchanged.
The checking against reg16_inoutportreg can be had with a simple test of
a bit, and the value setting from inoutportreg can be replaced by using
the actual register's reg_type field.
Note that the so far redundant 2nd instance of OPERAND_TYPE_INOUTPORTREG
is left in place, for its use in type_names[].
This patch replaces AddrPrefixOp0 with AddrPrefixOpReg to indicate that
the size of register operand is controlled by the address size prefix.
This will be used by Intel MOVDIRI and MOVDIR64B instructions later.
gas/
* config/tc-i386.c (process_suffix): Check addrprefixopreg
instead of addrprefixop0.
opcodes/
* i386-gen.c (opcode_modifiers): Replace AddrPrefixOp0 with
AddrPrefixOpReg.
* i386-opc.h (AddrPrefixOp0): Renamed to ...
(AddrPrefixOpReg): This.
(i386_opcode_modifier): Rename addrprefixop0 to addrprefixopreg.
* i386-opc.tbl: Replace AddrPrefixOp0 with AddrPrefixOpReg.
All of AVX, LWP, MPX, and PKU require XSAVE, and hence it as well as
XRSTOR should be enabled when enabling these ISA extensions. Leverage
these implications to shorten some of the cpu_flag_init[] entries.
It's not clear to me why they had been introduced - the respective
comments in opcodes/i386-gen.c are certainly wrong: ymm<N> registers
are very well supported (and necessary) with just AVX512F.
Neither 287 wrt 8087 nor 387 wrt 287 are proper supersets - in each case
some insns get removed from the ISA (they become NOPs, but code intended
for newer co-processors should not use them).
Furthermore with .no87, ST should not be recognized as a register name.
It again can be inferred from other information.
The vpopcntd templates all need to have Dword added to their memory
operands; the lack thereof was actually a bug preventing certain Intel
syntax code to assemble, so test cases get extended.
On x86, some instructions have alternate shorter encodings:
1. When the upper 32 bits of destination registers of
andq $imm31, %r64
testq $imm31, %r64
xorq %r64, %r64
subq %r64, %r64
known to be zero, we can encode them without the REX_W bit:
andl $imm31, %r32
testl $imm31, %r32
xorl %r32, %r32
subl %r32, %r32
This optimization is enabled with -O, -O2 and -Os.
2. Since 0xb0 mov with 32-bit destination registers zero-extends 32-bit
immediate to 64-bit destination register, we can use it to encode 64-bit
mov with 32-bit immediates. This optimization is enabled with -O, -O2
and -Os.
3. Since the upper bits of destination registers of VEX128 and EVEX128
instructions are extended to zero, if all bits of destination registers
of AVX256 or AVX512 instructions are zero, we can use VEX128 or EVEX128
encoding to encode AVX256 or AVX512 instructions. When 2 source
registers are identical, AVX256 and AVX512 andn and xor instructions:
VOP %reg, %reg, %dest_reg
can be encoded with
VOP128 %reg, %reg, %dest_reg
This optimization is enabled with -O2 and -Os.
4. 16-bit, 32-bit and 64-bit register tests with immediate may be
encoded as 8-bit register test with immediate. This optimization is
enabled with -Os.
This patch does:
1. Add {nooptimize} pseudo prefix to disable instruction size
optimization.
2. Add optimize to i386_opcode_modifier to tell assembler that encoding
of an instruction may be optimized.
gas/
PR gas/22871
* NEWS: Mention -O[2|s].
* config/tc-i386.c (_i386_insn): Add no_optimize.
(optimize): New.
(optimize_for_space): Likewise.
(fits_in_imm7): New function.
(fits_in_imm31): Likewise.
(optimize_encoding): Likewise.
(md_assemble): Call optimize_encoding to optimize encoding.
(parse_insn): Handle {nooptimize}.
(md_shortopts): Append "O::".
(md_parse_option): Handle -On.
* doc/c-i386.texi: Document -O0, -O, -O1, -O2 and -Os as well
as {nooptimize}.
* testsuite/gas/cfi/cfi-x86_64.d: Pass -O0 to assembler.
* testsuite/gas/i386/ilp32/cfi/cfi-x86_64.d: Likewise.
* testsuite/gas/i386/i386.exp: Run optimize-1, optimize-2,
optimize-3, x86-64-optimize-1, x86-64-optimize-2,
x86-64-optimize-3 and x86-64-optimize-4.
* testsuite/gas/i386/optimize-1.d: New file.
* testsuite/gas/i386/optimize-1.s: Likewise.
* testsuite/gas/i386/optimize-2.d: Likewise.
* testsuite/gas/i386/optimize-2.s: Likewise.
* testsuite/gas/i386/optimize-3.d: Likewise.
* testsuite/gas/i386/optimize-3.s: Likewise.
* testsuite/gas/i386/x86-64-optimize-1.s: Likewise.
* testsuite/gas/i386/x86-64-optimize-1.d: Likewise.
* testsuite/gas/i386/x86-64-optimize-2.d: Likewise.
* testsuite/gas/i386/x86-64-optimize-2.s: Likewise.
* testsuite/gas/i386/x86-64-optimize-3.d: Likewise.
* testsuite/gas/i386/x86-64-optimize-3.s: Likewise.
* testsuite/gas/i386/x86-64-optimize-4.d: Likewise.
* testsuite/gas/i386/x86-64-optimize-4.s: Likewise.
opcodes/
PR gas/22871
* i386-gen.c (opcode_modifiers): Add Optimize.
* i386-opc.h (Optimize): New enum.
(i386_opcode_modifier): Add optimize.
* i386-opc.tbl: Add "Optimize" to "mov $imm, reg",
"sub reg, reg/mem", "test $imm, acc", "test $imm, reg/mem",
"and $imm, acc", "and $imm, reg/mem", "xor reg, reg/mem",
"movq $imm, reg" and AVX256 and AVX512 versions of vandnps,
vandnpd, vpandn, vpandnd, vpandnq, vxorps, vxorpd, vpxor,
vpxord and vpxorq.
* i386-tbl.h: Regenerated.
