Most platforms only use a single MOV const operand - remove the MOV{B,H,W}const
operands from riscv64 and consistently use MOVDconst instead. The implementation
of all four is the same and there is no benefit gained from having multiple const
operands (in fact it requires a lot more rewrite rules).
Change-Id: I0ba7d7554e371a1de762ef5f3745e9c0c30d41ac
Reviewed-on: https://go-review.googlesource.com/c/go/+/302610
Trust: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Michael Munday <mike.munday@lowrisc.org>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
The 32 bit versions are easily implement with a single instruction, while the
8 bit versions require a bit more effort but use the same atomic instructions
via rewrite rules.
Change-Id: I42e8d457b239c8f75e39a8e282fc88c1bb292a99
Reviewed-on: https://go-review.googlesource.com/c/go/+/268098
Trust: Joel Sing <joel@sing.id.au>
Run-TryBot: Joel Sing <joel@sing.id.au>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Implement runtime.duffzero and runtime.duffcopy for riscv64.
Use obj.ADUFFZERO/obj.ADUFFCOPY for medium size, word aligned
zeroing/moving.
Change-Id: I42ec622055630c94cb77e286d8d33dbe7c9f846c
Reviewed-on: https://go-review.googlesource.com/c/go/+/237797
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Add additional rules to eliminate unnecessary sign/zero extension for riscv64.
Also where possible, replace an extension following a load with a different typed
load. This removes almost another 8,000 instructions from the go binary.
Of particular note, change Eq16/Eq8/Neq16/Neq8 to zero extend each value before
subtraction, rather than zero extending after subtraction. While this appears to
double the number of zero extensions, it often lets us completely eliminate them
as the load can already be performed in a properly typed manner.
As an example, prior to this change runtime.memequal16 was:
0000000000013028 <runtime.memequal16>:
13028: 00813183 ld gp,8(sp)
1302c: 00019183 lh gp,0(gp)
13030: 01013283 ld t0,16(sp)
13034: 00029283 lh t0,0(t0)
13038: 405181b3 sub gp,gp,t0
1303c: 03019193 slli gp,gp,0x30
13040: 0301d193 srli gp,gp,0x30
13044: 0011b193 seqz gp,gp
13048: 00310c23 sb gp,24(sp)
1304c: 00008067 ret
Whereas it now becomes:
0000000000012fa8 <runtime.memequal16>:
12fa8: 00813183 ld gp,8(sp)
12fac: 0001d183 lhu gp,0(gp)
12fb0: 01013283 ld t0,16(sp)
12fb4: 0002d283 lhu t0,0(t0)
12fb8: 405181b3 sub gp,gp,t0
12fbc: 0011b193 seqz gp,gp
12fc0: 00310c23 sb gp,24(sp)
12fc4: 00008067 ret
Change-Id: I16321feb18381241cab121c0097a126104c56c2c
Reviewed-on: https://go-review.googlesource.com/c/go/+/264659
Trust: Joel Sing <joel@sing.id.au>
Run-TryBot: Joel Sing <joel@sing.id.au>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Rather than handling sign and zero extension via rules, defer to the assembler
and use MOV pseudo-instructions. The instruction can also be omitted where the
type and size is already correct. This change results in more than 6,000
instructions being removed from the go binary (in part due to omitted
instructions, in part due to MOVBU having a more efficient implementation in
the assembler than what is used in the current ZeroExt8to{16,32,64} rules).
This will also allow for further rewriting to remove redundant sign/zero
extension.
Change-Id: I05e42fd9f09f40a69948be7de772cce8946c8744
Reviewed-on: https://go-review.googlesource.com/c/go/+/264658
Trust: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The original riscv64 port used the thread pointer (TP aka X4) register for
the g pointer, however this register is also used when TLS support is
required, resulting in a conflict (for example, when a signal is received
we have no way of readily knowing if X4 contains a pointer to the TCB or
a pointer to a g).
In order to support cgo, free up the X4 register by moving g to X27.
This unfortunately means that the X4 register is unused in non-cgo mode,
however the alternative is to not support cgo on this platform.
Update #36641
Change-Id: Idcaf3e8ccbe42972a1b8943aeefde7149d9c960a
Reviewed-on: https://go-review.googlesource.com/c/go/+/263477
Trust: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This is prerequisite to moving call expansion later into SSA,
and probably a good idea anyway. Passes tests.
This is the first minimal CL that does a 1-for-1 substitution
of *ssa.AuxCall for *obj.LSym. Next step (next CL) is to make
this change for all calls so that additional information can
be stored in AuxCall.
Change-Id: Ia3a7715648fd9fb1a176850767a726e6f5b959eb
Reviewed-on: https://go-review.googlesource.com/c/go/+/237680
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This makes the intent clearer, allows for another ellipsis and will aid
in future rewriting. While here, document boolean loads to explain register
contents.
Change-Id: I933db2813826d88819366191fbbea8fcee5e4dda
Reviewed-on: https://go-review.googlesource.com/c/go/+/230120
Reviewed-by: Keith Randall <khr@golang.org>
PanicBounds and PanicExtend are lowered to runtime calls (with a
non-Go ABI), but are not currently marked as calls. Since liveness
analysis only emits stack maps at calls in the runtime, this means
these panic call sites in the runtime won't get a stack map. These
almost immediately turn into throws in the runtime, but there's still
a chance they'll try to grow the stack first, which would lead to a
different panic.
To fix this, mark these operations as calls.
Outside the runtime, we currently emit stack maps for everything that
isn't an unsafe-point, so these panic calls get stack maps by default.
However, we're about to move to emitting stack maps only at call
sites, at which point this will start to matter outside the runtime as
well.
I confirmed that this has no effect on anything but PCDATA/FUNCDATA in
runtime and net/http.
For #36365.
Change-Id: Ic5bb463fd152cc320c815dc04cf62005261ae169
Reviewed-on: https://go-review.googlesource.com/c/go/+/230539
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Implement multi-control branches for riscv64, switching to using the BNEZ
pseudo-instruction when rewriting conditionals. This will allow for further
branch optimisations to later be performed via rewrites.
Change-Id: I7f2c69f3c77494b403f26058c6bc8432d8070ad0
Reviewed-on: https://go-review.googlesource.com/c/go/+/226399
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Joel Sing <joel@sing.id.au>
Where possible, fold constants into versions of instructions that take
an immediate. This avoids the need to allocate a register and load the
immediate into it.
Change-Id: If911ca41235e218490679aed2ce5f48bf807a2b3
Reviewed-on: https://go-review.googlesource.com/c/go/+/222639
Run-TryBot: Joel Sing <joel@sing.id.au>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Also rewrite subtraction of zero to NEG/NEGW.
Change-Id: I216e286d1860055f2a07fe2f772cd50f366ea097
Reviewed-on: https://go-review.googlesource.com/c/go/+/221691
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This allows for zero stores to be performed using the zero register, rather
than loading a separate register with zero.
Change-Id: Ic81d8dbcdacbb2ca2c3f77682ff5ad7cdc33d18d
Reviewed-on: https://go-review.googlesource.com/c/go/+/221684
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
SignExt32to64 can be implemented with a single ADDIW instruction, rather than
the two shifts that are in use currently.
Change-Id: Ie1bbaef4018f1ba5162773fc64fa5a887457cfc9
Reviewed-on: https://go-review.googlesource.com/c/go/+/220922
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Use SUBW to perform a 32-bit subtraction, rather than zero extending from
32 to 64 bits. This reduces Eq32 and Neq32 to two instructions, rather than
the four instructions required previously.
Change-Id: Ib2798324881e9db842c864e91a0c1b1e48c4b67b
Reviewed-on: https://go-review.googlesource.com/c/go/+/220921
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Duplicate the register definitions and names to avoid importing the
cmd/internal/obj/riscv64 package. This makes it possible to build compiler rules
with a stable Go tool chain.
Fixes#36663
Change-Id: I09116a97bb037ca1bc00073306a82bb88862b1e9
Reviewed-on: https://go-review.googlesource.com/c/go/+/216518
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Based on riscv-go port.
Updates #27532
Change-Id: Ia329daa243db63ff334053b8807ea96b97ce3acf
Reviewed-on: https://go-review.googlesource.com/c/go/+/204631
Run-TryBot: Joel Sing <joel@sing.id.au>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
