There's little point carrying up to three templates per insn flavor
when the sole difference is operand size and the dependency on AVX512VL
being enabled. Instead the need for AVX512VL can be derived from an
operand allowing for ZMMword as well as one or both or XMMword and
YMMword (irrespective of whether this is a register or memory operand).
Without further abstraction to deal with the different Disp8MemShift
values between the templates, only a limited set (mostly ones only
allowing for non-memory operands) can be folded, which is being done
here.
Also drop IgnoreSize wherever possible from anything that's being
touched anyway.
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.
Since only the first 32 bits of input operand are used for tpause and
umwait, the REX.W bit is skipped. Both 32-bit registers and 64-bit
registers are allowed.
gas/
* testsuite/gas/i386/x86-64-waitpkg.s: Add 32-bit registers
tests for tpause and umwait.
* testsuite/gas/i386/x86-64-waitpkg-intel.d: Updated.
* testsuite/gas/i386/x86-64-waitpkg.d: Likewise.
opcodes/
* i386-dis.c (prefix_table): Replace Em with Edq on tpause and
umwait.
* i386-opc.tbl: Allow 32-bit registers for tpause and umwait in
64-bit mode.
* i386-tbl.h: Regenerated.
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.
The wrong placement of the Load attribute in the templates prevented
this from working. The disassembler also didn't handle this consistently
with other similar dual-encoding insns.
While many templates allowing multiple suitably matching XMM/YMM/ZMM
operand sizes can be folded, a few need to be split in order to not
wrongly accept "xmmword ptr" operands when only XMM registers are
permitted (and memory operands are more narrow). Add a test case
validating this.
"clr reg" is an alias of "xor reg, reg". We can encode "clr reg64" as
"xor reg32, reg32".
gas/
* config/tc-i386.c (optimize_encoding): Also encode "clr reg64"
as "xor reg32, reg32".
* testsuite/gas/i386/x86-64-optimize-1.s: Add "clr reg64" tests.
* testsuite/gas/i386/x86-64-optimize-1.d: Updated.
opcodes/
* i386-opc.tbl: Add Optimize to clr.
* i386-tbl.h: Regenerated.
The differences between some of the register and memory forms of the
same insn often don't really require the templates to be separate. For
example, Disp8MemShift is simply irrelevant to register forms. Fold
these as far as possible, and also fold register-only forms. Further
folding is possible, but needs other prereq work done first.
A note regarding EVEXDYN: This is intended to be used only when no other
properties of the template would make is_evex_encoding() return true. In
all "normal" cases I think it is preferable to omit this indicator, to
keep the table half way readable.
Their memory forms were bogusly using VexLWP instead of VexNDD. Adjust
VexNDD handling to cope with these, allowing their register and memory
forms to be folded.
The differences between some of the register and memory forms of the
same insn often don't really require the templates to be separate. For
example, Disp8MemShift is simply irrelevant to register forms. Fold them
as far as possible. Further folding is possible, but needs other prereq
work done first.
They aren't really useful (anymore?): The conflicting operand size check
isn't applicable to any insn validly using respective memory operand
sizes (and if they're used wrongly, another error would result), and the
logic in process_suffix() can be easily changed to work without them.
While re-structuring conditionals in process_suffix() also drop the
CMPXCHG8B special case in favor of a NoRex64 attribute in the opcode
table.
Neither touches any XMM register, so the check is pointless. It is imo
even questionable whether in SSE2AVX mode the two should be converted to
their AVX counterparts.
This requires a change to ModR/M handling: Recording of displacement
types must not discard operand size information. Change the respective
code to alter only .disp<N>.
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.
Add {rex} pseudo prefix to generate a REX byte for integer and legacy
vector instructions if possible. Note that this differs from the rex
prefix which generates REX prefix unconditionally.
gas/
* config/tc-i386.c (_i386_insn): Add rex_encoding.
(md_assemble): When i.rex_encoding is true, generate a REX byte
if possible.
(parse_insn): Set i.rex_encoding for {rex}.
* doc/c-i386.texi: Document {rex}.
* testsuite/gas/i386/x86-64-pseudos.s: Add {rex} tests.
* testsuite/gas/i386/x86-64-pseudos.d: Updated.
opcodes/
* i386-opc.tbl: Add {rex},
* i386-tbl.h: Regenerated.
Just like their packed counterparts the memory operand is always 16
bytes wide, and the Disp8 scaling is the same for all of them. (As a
side note: I'm also surprised by there being AVX512VL variants of
these as well as the AVX512_4VNNIW ones - the SDM doesn't define any
such.)
Adjust the test cases also for the packed forms to actually live up to
their promise of testing correct Disp8 encoding.
For historical reason, we allow movd/vmovd with 64-bit register and
memeory operands. But for vmovd, we failed to handle 64-bit memeory
operand. This has been gone unnoticed since AT&T syntax always treats
memory operand as 32-bit memory. This patch properly encodes vmovd
with 64-bit memeory operands. It also removes AVX512 vmovd with 64-bit
operands since GCC has
case TYPE_SSEMOV:
switch (get_attr_mode (insn))
{
case MODE_DI:
/* Handle broken assemblers that require movd instead of movq. */
if (!HAVE_AS_IX86_INTERUNIT_MOVQ
&& (GENERAL_REG_P (operands[0]) || GENERAL_REG_P (operands[1])))
return "%vmovd\t{%1, %0|%0, %1}";
return "%vmovq\t{%1, %0|%0, %1}";
and all AVX512 GNU assemblers set HAVE_AS_IX86_INTERUNIT_MOVQ, GCC won't
generate AVX512 vmovd with 64-bit operand.
gas/
PR gas/22681
* testsuite/gas/i386/i386.exp: Run x86-64-movd and
x86-64-movd-intel.
* testsuite/gas/i386/x86-64-movd-intel.d: New file.
* testsuite/gas/i386/x86-64-movd.d: Likewise.
* testsuite/gas/i386/x86-64-movd.s: Likewise.
opcodes/
PR gas/22681
* i386-opc.tbl: Properly encode vmovd with Qword memeory operand.
Remove AVX512 vmovd with 64-bit operands.
* i386-tbl.h: Regenerated.
Just like for instructions in GPRs, there's no need to have separate
templates for otherwise identical insns acting on XMM or YMM registers
(or memory of the same size).
Use a combination of a single new Reg bit and Byte, Word, Dword, or
Qword instead.
Besides shrinking the number of operand type bits this has the benefit
of making register handling more similar to accumulator handling (a
generic flag is being accompanied by a "size qualifier"). It requires,
however, to split a few insn templates, as it is no longer correct to
have combinations like Reg32|Reg64|Byte. This slight growth in size will
hopefully be outweighed by this change paving the road for folding a
presumably much larger number of templates later on.
They are relevant only when multiple operands permit registers:
operand_type_register_match() returns true if either operand is not a
register one. IOW
grep -i CheckRegSize i386-opc.tbl | grep -Ev "(Reg[8136]|Acc).*,.*(Reg|Acc)"
should produce no output.
BaseIndex implies - with the exception of string instructions the
optional presence of a displacement. This is almost completely uniform
for all instructions (the sole exception being MPX ones, which don't
allow 16-bit addressing and hence Disp16), so there's no point in
explicitly stating this in the main opcode table. Drop those explict
specifications in favor of adding logic to i386-gen, shrinking the
table size quite a bit and hence making it more readable.
The opcodes/i386-tbl.h changes are due to a few cases where pointless
Disp* still hadn't been removed from their insns.
H.J. Lu
Igor Tsimbalist
Jan Beulich
Alan Modra