Currently we only include static entries in the hint for sizing
the map when allocating a map for a map literal. Change that to
include all entries.
This will be an overallocation if the dynamic entries in the map have
equal keys, but equal keys in map literals are rare, and at worst we
waste a bit of space.
Fixes#43020
Change-Id: I232f82f15316bdf4ea6d657d25a0b094b77884ce
Reviewed-on: https://go-review.googlesource.com/c/go/+/383634
Run-TryBot: Keith Randall <khr@golang.org>
Trust: Keith Randall <khr@golang.org>
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Updated multiple tests in test/codegen/arithmetic.go to verify
on ppc64/ppc64le as well
Change-Id: I79ca9f87017ea31147a4ba16f5d42ba0fcae64e1
Reviewed-on: https://go-review.googlesource.com/c/go/+/358546
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Go Bot <gobot@golang.org>
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Reviewed-by: Cherry Mui <cherryyz@google.com>
In CL 354670, I copied some existing rules for convenience but forgot
to update the last rule which broke `GOAMD64=v3 ./make.bat`
Revive CL 354670
Change-Id: Ic1e2047c603f0122482a4b293ce1ef74d806c019
Reviewed-on: https://go-review.googlesource.com/c/go/+/356810
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Keith Randall <khr@golang.org>
Trust: Daniel Martí <mvdan@mvdan.cc>
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It was noticed through some other investigation that BitLen32
was not generating the best code and found that it wasn't recognized
as an intrinsic. This corrects that and enables the test for PPC64.
Change-Id: Iab496a8830c8552f507b7292649b1b660f3848b5
Reviewed-on: https://go-review.googlesource.com/c/go/+/355872
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The code generated when storing eight bytes loaded from memory in big
endian introduced two successive byte swaps that did not actually
modified the data.
The new rules match this specific pattern both for amd64 and for arm64,
eliminating the double swap.
Fixes#41684
Change-Id: Icb6dc20b68e4393cef4fe6a07b33aba0d18c3ff3
Reviewed-on: https://go-review.googlesource.com/c/go/+/320073
Reviewed-by: Keith Randall <khr@golang.org>
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Trust: Daniel Martí <mvdan@mvdan.cc>
Trust: Dmitri Shuralyov <dmitshur@golang.org>
This CL adds late expanded memequal(x, const, sz) inlining for 2, 4, 8
bytes size. This PoC is using the same method as CL 248404.
This optimization fires about 100 times in Go compiler (1675 occurrences
reduced to 1574, so -6%).
Also, added unit-tests to codegen/comparisions.go file.
Updates #37275
Change-Id: Ia52808d573cb706d1da8166c5746ede26f46c5da
Reviewed-on: https://go-review.googlesource.com/c/go/+/328291
Reviewed-by: Cherry Mui <cherryyz@google.com>
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Trust: David Chase <drchase@google.com>
In case of amd64 the compiler issues checks if extensions are
available on a platform. With GOAMD64 microarchitecture levels
provided, some of the checks could be eliminated.
Change-Id: If15c178bcae273b2ce7d3673415cb8849292e087
Reviewed-on: https://go-review.googlesource.com/c/go/+/352010
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Reviewed-by: Matthew Dempsky <mdempsky@google.com>
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This updates the codegen tests in noextend.go so they are not
dependent on the ABI.
Change-Id: I8433bea9dc78830c143290a7e0cf901b2397d38a
Reviewed-on: https://go-review.googlesource.com/c/go/+/353070
Trust: Lynn Boger <laboger@linux.vnet.ibm.com>
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Add rule to PPC64.rules to inline runtime.memmove in more cases, as is
done for other target architectures
Updated tests in codegen/copy.go to verify changes are done on
ppc64/ppc64le
Updates #41662
Change-Id: Id937ce21f9b4f4047b3e66dfa3c960128ee16a2a
Reviewed-on: https://go-review.googlesource.com/c/go/+/352054
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Instructions with immediates can be precomputed when operating on a
constant - do so for SLTI/SLTIU, SLLI/SRLI/SRAI, NEG/NEGW, ANDI, ORI
and ADDI. Additionally, optimise ANDI and ORI when the immediate is
all ones or all zeroes.
In particular, the RISCV64 logical left and right shift rules
(Lsh*x*/Rsh*Ux*) produce sequences that check if the shift amount
exceeds 64 and if so returns zero. When the shift amount is a
constant we can precompute and eliminate the filter entirely.
Likewise the arithmetic right shift rules produce sequences that
check if the shift amount exceeds 64 and if so, ensures that the
lower six bits of the shift are all ones. When the shift amount
is a constant we can precompute the shift value.
Arithmetic right shift sequences like:
117fc: 00100513 li a0,1
11800: 04053593 sltiu a1,a0,64
11804: fff58593 addi a1,a1,-1
11808: 0015e593 ori a1,a1,1
1180c: 40b45433 sra s0,s0,a1
Are now a single srai instruction:
117fc: 40145413 srai s0,s0,0x1
Likewise for logical left shift (and logical right shift):
1d560: 01100413 li s0,17
1d564: 04043413 sltiu s0,s0,64
1d568: 40800433 neg s0,s0
1d56c: 01131493 slli s1,t1,0x11
1d570: 0084f433 and s0,s1,s0
Which are now a single slli (or srli) instruction:
1d120: 01131413 slli s0,t1,0x11
This removes more than 30,000 instructions from the Go binary and
should improve performance in a variety of areas - of note
runtime.makemap_small drops from 48 to 36 instructions. Similar
gains exist in at least other parts of runtime and math/bits.
Change-Id: I33f6f3d1fd36d9ff1bda706997162bfe4bb859b6
Reviewed-on: https://go-review.googlesource.com/c/go/+/350689
Trust: Joel Sing <joel@sing.id.au>
Reviewed-by: Michael Munday <mike.munday@lowrisc.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Add tests for shift by constant, masked shifts and bounded shifts. While here,
sort tests by architecture and keep order of tests consistent (lsh, rshU, rsh).
Change-Id: I512d64196f34df9cb2884e8c0f6adcf9dd88b0fc
Reviewed-on: https://go-review.googlesource.com/c/go/+/351289
Trust: Joel Sing <joel@sing.id.au>
Reviewed-by: Michael Munday <mike.munday@lowrisc.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
BMI1 includes four instructions (ANDN, BLSI, BLSMSK, BLSR) that are
easy to peephole optimize, and which GCC always seems to favor using
when available and applicable.
Updates #45453.
Change-Id: I0274184057058f5c579e5bc3ea9c414396d3cf46
Reviewed-on: https://go-review.googlesource.com/c/go/+/351130
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Trust: Matthew Dempsky <mdempsky@google.com>
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Reviewed-by: Keith Randall <khr@golang.org>
Also, add the FABSS and FABSD pseudo instructions to the assembler.
The compiler could use FSGNJX[SD] directly but there doesn't seem
to be much advantage to doing so and the pseudo instructions are
easier to understand.
Change-Id: Ie8825b8aa8773c69cc4f07a32ef04abf4061d80d
Reviewed-on: https://go-review.googlesource.com/c/go/+/348989
Trust: Michael Munday <mike.munday@lowrisc.org>
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Reviewed-by: Joel Sing <joel@sing.id.au>
In some rewrite rules for arm64 bitfield optimizations, the
bitfield lsb value and the bitfield width value are related
to datasize, some of them use datasize directly to check the
bitfield lsb value is valid, to get the bitfiled width value,
but some of them call isARM64BFMask() and arm64BFWidth()
functions. In order to be consistent, this patch changes them
all to use datasize.
Besides, this patch sorts the codegen test cases.
Run the "toolstash-check -all" command and find one inconsistent code
is as the following.
new: src/math/fma.go:104 BEQ 247
master: src/math/fma.go:104 BEQ 248
The above inconsistence is due to this patch changing the range of the
field lsb value in "UBFIZ" optimization rules from "lc+(32|16|8)<64" to
"lc<64", so that the following code is generated as "UBFIZ". The logical
of changed code is still correct.
The code of src/math/fma.go:160:
const uvinf = 0x7FF0000000000000
func FMA(a, b uint32) float64 {
ps := a+b
return Float64frombits(uint64(ps)<<63 | uvinf)
}
The new assembly code:
TEXT "".FMA(SB), LEAF|NOFRAME|ABIInternal, $0-16
MOVWU "".a(FP), R0
MOVWU "".b+4(FP), R1
ADD R1, R0, R0
UBFIZ $63, R0, $1, R0
ORR $9218868437227405312, R0, R0
MOVD R0, "".~r2+8(FP)
RET (R30)
The master assembly code:
TEXT "".FMA(SB), LEAF|NOFRAME|ABIInternal, $0-16
MOVWU "".a(FP), R0
MOVWU "".b+4(FP), R1
ADD R1, R0, R0
MOVWU R0, R0
LSL $63, R0, R0
ORR $9218868437227405312, R0, R0
MOVD R0, "".~r2+8(FP)
RET (R30)
Change-Id: I9061104adfdfd3384d0525327ae1e5c8b0df5c35
Reviewed-on: https://go-review.googlesource.com/c/go/+/265038
Trust: fannie zhang <Fannie.Zhang@arm.com>
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The codegen tests are currently skipped (see #48247). The test
added in CL 346050 did not compile because it was in the main
package but did not contain a main function. Changing the package
to 'codegen' fixes the issue.
Updates #48247.
Change-Id: I0a0eaca8e6a7d7b335606d2c76a204ac0c12e6d5
Reviewed-on: https://go-review.googlesource.com/c/go/+/348392
Trust: Michael Munday <mike.munday@lowrisc.org>
Run-TryBot: Michael Munday <mike.munday@lowrisc.org>
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TryBot-Result: Go Bot <gobot@golang.org>
The codegen tests are currently skipped (see #48247) and the
bitfield tests do not actually compile due to a duplicate function
name (sbfiz5) added in CL 267602. Renaming the function fixes the
issue.
Updates #48247.
Change-Id: I626fd5ef13732dc358e73ace9ddcc4cbb6ae5b21
Reviewed-on: https://go-review.googlesource.com/c/go/+/348391
Trust: Michael Munday <mike.munday@lowrisc.org>
Run-TryBot: Michael Munday <mike.munday@lowrisc.org>
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Reviewed-by: Cherry Mui <cherryyz@google.com>
This test is not executed by default (see #48247) and does not
actually pass. It was added in CL 346689. The code generation
changes made in that CL only change how instructions are assembled,
they do not actually affect the output of the compiler. This test
is unfortunately therefore invalid and will never pass.
Updates #48247.
Change-Id: I0c807e4a111336e5a097fe4e3af2805f9932a87f
Reviewed-on: https://go-review.googlesource.com/c/go/+/348390
Trust: Michael Munday <mike.munday@lowrisc.org>
Run-TryBot: Michael Munday <mike.munday@lowrisc.org>
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TryBot-Result: Go Bot <gobot@golang.org>
The most common cases:
len(s) > 0
len(s) < 1
and they can be simplified to:
len(s) != 0
len(s) == 0
Fixes#48054
Change-Id: I16e5b0cffcfab62a4acc2a09977a6cd3543dd000
Reviewed-on: https://go-review.googlesource.com/c/go/+/346050
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
This patch adds some rules to rewrite "(LeftShift (SignExtend x) lc)"
expression as "SBFIZ".
Add the test cases.
Change-Id: I294c4ba09712eeb02c7a952447bb006780f1e60d
Reviewed-on: https://go-review.googlesource.com/c/go/+/267602
Trust: fannie zhang <Fannie.Zhang@arm.com>
Trust: Cherry Mui <cherryyz@google.com>
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The UBFX and SBFX already zero/sign extend the result. Further
zero/sign extensions are thus unnecessary as long as they leave
the top bits unaltered. This patch absorbs zero/sign extensions
into UBFX/SBFX.
Add the related test cases.
Change-Id: I7c4516c8b52d677f77bf3aaedab87c4a28056ec0
Reviewed-on: https://go-review.googlesource.com/c/go/+/265039
Trust: fannie zhang <Fannie.Zhang@arm.com>
Trust: Keith Randall <khr@golang.org>
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Reviewed-by: Cherry Mui <cherryyz@google.com>
This CL simplifies riscv addition (add r, imm) to
(ADDI (ADDI r, imm/2), imm-imm/2) if imm is in specific ranges.
(-4096 <= imm <= -2049 or 2048 <= imm <= 4094)
There is little impact to the go1 benchmark, while the total
size of pkg/linux_riscv64 decreased by about 11KB.
Change-Id: I236eb8af3b83bb35ce9c0b318fc1d235e8ab9a4e
GitHub-Last-Rev: a2f56a0763
GitHub-Pull-Request: golang/go#48110
Reviewed-on: https://go-review.googlesource.com/c/go/+/346689
Run-TryBot: Ben Shi <powerman1st@163.com>
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Reviewed-by: Keith Randall <khr@golang.org>
Trust: Michael Munday <mike.munday@lowrisc.org>
Add support to the assembler for F[N]M{ADD,SUB}[SD] instructions.
Argument order is:
OP RS1, RS2, RS3, RD
Also, add support for the FMA intrinsic to the compiler. Automatic
FMA matching is left to a future CL.
Change-Id: I47166c7393b2ab6bfc2e42aa8c1a8997c3a071b3
Reviewed-on: https://go-review.googlesource.com/c/go/+/293030
Trust: Michael Munday <mike.munday@lowrisc.org>
Run-TryBot: Michael Munday <mike.munday@lowrisc.org>
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Reviewed-by: Joel Sing <joel@sing.id.au>
For debugging.
Change-Id: I5875ccd2413b8ffd2ec97a0ace66b5cae7893b24
Reviewed-on: https://go-review.googlesource.com/c/go/+/324765
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In codegen/arithmetic.go, previously there are MOVD's that match
for loads of arguments. With register ABI there are no more such
loads. Remove the MOVD matches.
Change-Id: I920ee2629c8c04d454f13a0c08e283d3528d9a64
Reviewed-on: https://go-review.googlesource.com/c/go/+/324251
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This CL add runtime.memmove inlining for AMD64 and ARM64.
According to ssa dump from testcases generic rules can't inline
memmomve properly due to one of the arguments is Phi operation. But this
Phi op will be optimized out by later optimization stages. As a result
memmove can be inlined during arch-specific rules.
The commit add new optimization rules to arch-specific rules that can
inline runtime.memmove if it possible during lowering stage.
Optimization fires 5 times in Go source-code using regabi.
Fixes#41662
Change-Id: Iaffaf4c482d068b5f0683d141863892202cc8824
Reviewed-on: https://go-review.googlesource.com/c/go/+/289151
Reviewed-by: Keith Randall <khr@golang.org>
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These operations (BT{S,R,C}{Q,L}modify) are quite a bit slower than
other ways of doing the same thing.
Without the BTxmodify operations, there are two fallback ways the compiler
performs these operations: AND/OR/XOR operations directly on memory, or
load-BTx-write sequences. The compiler kinda chooses one arbitrarily
depending on rewrite rule application order. Currently, it uses
load-BTx-write for the Const benchmarks and AND/OR/XOR directly to memory
for the non-Const benchmarks. TBD, someone might investigate which of
the two fallback strategies is really better. For now, they are both
better than BTx ops.
name old time/op new time/op delta
BitSet-8 1.09µs ± 2% 0.64µs ± 5% -41.60% (p=0.000 n=9+10)
BitClear-8 1.15µs ± 3% 0.68µs ± 6% -41.00% (p=0.000 n=10+10)
BitToggle-8 1.18µs ± 4% 0.73µs ± 2% -38.36% (p=0.000 n=10+8)
BitSetConst-8 37.0ns ± 7% 25.8ns ± 2% -30.24% (p=0.000 n=10+10)
BitClearConst-8 30.7ns ± 2% 25.0ns ±12% -18.46% (p=0.000 n=10+10)
BitToggleConst-8 36.9ns ± 1% 23.8ns ± 3% -35.46% (p=0.000 n=9+10)
Fixes#45790
Update #45242
Change-Id: Ie33a72dc139f261af82db15d446cd0855afb4e59
Reviewed-on: https://go-review.googlesource.com/c/go/+/318149
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Currently, if we have AX=a and BX=b, and we want to make a call
F(1, a, b), to move arguments into the desired registers it emits
MOVQ AX, CX
MOVL $1, AX // AX=1
MOVQ BX, DX
MOVQ CX, BX // BX=a
MOVQ DX, CX // CX=b
This has a few redundant moves.
This is because we process inputs in order. First, allocate 1 to
AX, which kicks out a (in AX) to CX (a free register at the
moment). Then, allocate a to BX, which kicks out b (in BX) to DX.
Finally, put b to CX.
Notice that if we start with allocating CX=b, then BX=a, AX=1,
we will not have redundant moves. This CL reduces redundant moves
by allocating them in different order: First, for inpouts that are
already in place, keep them there. Then allocate free registers.
Then everything else.
before after
cmd/compile binary size 23703888 23609680
text size 8565899 8533291
(with regabiargs enabled.)
Change-Id: I69e1bdf745f2c90bb791f6d7c45b37384af1e874
Reviewed-on: https://go-review.googlesource.com/c/go/+/311371
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Fixes this failure:
go test cmd/compile/internal/ssa -run TestStmtLines -v
=== RUN TestStmtLines
stmtlines_test.go:115: Saw too many (amd64, > 1%) lines without
statement marks, total=88263, nostmt=1930
('-run TestStmtLines -v' lists failing lines)
The failure has two causes.
One is that the first-line adjuster in code generation was relocating
"first lines" to instructions that would either not have any code generated,
or would have the statment marker removed by a different believed-good heuristic.
The other was that statement boundaries were getting attached to register
values (that with the old ABI were loads from the stack, hence real instructions).
The register values disappear at code generation.
The fixes are to (1) note that certain instructions are not good choices for
"first value" and skip them, and (2) in an expandCalls post-pass, look for
register valued instructions and under appropriate conditions move their
statement marker to a compatible use.
Also updates TestStmtLines to always log the score, for easier comparison of
minor compiler changes.
Updates #40724.
Change-Id: I485573ce900e292d7c44574adb7629cdb4695c3f
Reviewed-on: https://go-review.googlesource.com/c/go/+/309649
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Some codegen tests were written with the assumption that
arguments and results are in memory, and with a specific stack
layout. With the register ABI, the assumption is no longer true.
Adjust the tests to work with both cases.
- For tests expecting in memory arguments/results, change to use
global variables or memory-assigned argument/results.
- Allow more registers. E.g. some tests expecting register names
contain only letters (e.g. AX), but it can also contain numbers
(e.g. R10).
- Some instruction selection changes when operate on register vs.
memory, e.g. ADDQ vs. LEAQ, MOVB vs. MOVL. Accept both.
TODO: mathbits.go and memops.go still need fix.
Change-Id: Ic5932b4b5dd3f5d30ed078d296476b641420c4c5
Reviewed-on: https://go-review.googlesource.com/c/go/+/309335
Trust: Cherry Zhang <cherryyz@google.com>
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Under certain circumstances, the existing rules for bit operations can
produce code that writes beyond its intended bounds. For example,
consider the following code:
func repro(b []byte, addr, bit int32) {
_ = b[3]
v := uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24 | 1<<(bit&31)
b[0] = byte(v)
b[1] = byte(v >> 8)
b[2] = byte(v >> 16)
b[3] = byte(v >> 24)
}
Roughly speaking:
1. The expression `1 << (bit & 31)` is rewritten into `(SHLL 1 bit)`
2. The expression `uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 |
uint32(b[3])<<24` is rewritten into `(MOVLload &b[0])`
3. The statements `b[0] = byte(v) ... b[3] = byte(v >> 24)` are
rewritten into `(MOVLstore &b[0], v)`
4. `(ORL (SHLL 1, bit) (MOVLload &b[0]))` is rewritten into
`(BTSL (MOVLload &b[0]) bit)`. This is a valid transformation because
the destination is a register: in this case, the bit offset is masked
by the number of bits in the destination register. This is identical
to the masking performed by `SHL`.
5. `(MOVLstore &b[0] (BTSL (MOVLload &b[0]) bit))` is rewritten into
`(BTSLmodify &b[0] bit)`. This is an invalid transformation because
the destination is memory: in this case, the bit offset is not
masked, and the chosen instruction may write outside its intended
32-bit location.
These changes fix the invalid rewrite performed in step (5) by
explicitly maksing the bit offset operand to `BT(S|R|C)(L|Q)modify`. In
the example above, the adjusted rules produce
`(BTSLmodify &b[0] (ANDLconst [31] bit))` in step (5).
These changes also add several new rules to rewrite bit sets, toggles,
and clears that are rooted at `(OR|XOR|AND)(L|Q)modify` operators into
appropriate `BT(S|R|C)(L|Q)modify` operators. These rules catch cases
where `MOV(L|Q)store ((OR|XOR|AND)(L|Q) ...)` is rewritten to
`(OR|XOR|AND)(L|Q)modify` before the `(OR|XOR|AND)(L|Q) ...` can be
rewritten to `BT(S|R|C)(L|Q) ...`.
Overall, compilecmp reports small improvements in code size on
darwin/amd64 when the changes to the compiler itself are exlcuded:
file before after Δ %
runtime.s 536464 536412 -52 -0.010%
bytes.s 32629 32593 -36 -0.110%
strings.s 44565 44529 -36 -0.081%
os/signal.s 7967 7959 -8 -0.100%
cmd/vendor/golang.org/x/sys/unix.s 81686 81678 -8 -0.010%
math/big.s 188235 188253 +18 +0.010%
cmd/link/internal/loader.s 89295 89056 -239 -0.268%
cmd/link/internal/ld.s 633551 633232 -319 -0.050%
cmd/link/internal/arm.s 18934 18928 -6 -0.032%
cmd/link/internal/arm64.s 31814 31801 -13 -0.041%
cmd/link/internal/riscv64.s 7347 7345 -2 -0.027%
cmd/compile/internal/ssa.s 4029173 4033066 +3893 +0.097%
total 21298280 21301472 +3192 +0.015%
Change-Id: I2e560548b515865129e1724e150e30540e9d29ce
GitHub-Last-Rev: 9a42bd29a5
GitHub-Pull-Request: golang/go#45242
Reviewed-on: https://go-review.googlesource.com/c/go/+/304869
Reviewed-by: Keith Randall <khr@golang.org>
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Optimize some patterns into rev16/rev16w instruction.
Pattern1:
(c & 0xff00ff00)>>8 | (c & 0x00ff00ff)<<8
To:
rev16w c
Pattern2:
(c & 0xff00ff00ff00ff00)>>8 | (c & 0x00ff00ff00ff00ff)<<8
To:
rev16 c
This patch is a copy of CL 239637, contributed by Alice Xu(dianhong.xu@arm.com).
Change-Id: I96936c1db87618bc1903c04221c7e9b2779455b3
Reviewed-on: https://go-review.googlesource.com/c/go/+/268377
Trust: fannie zhang <Fannie.Zhang@arm.com>
Run-TryBot: fannie zhang <Fannie.Zhang@arm.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
When -clobberdeadreg flag is set, the compiler inserts code that
clobbers integer registers at call sites. This may be helpful for
debugging register ABI.
Only implemented on AMD64 for now.
Change-Id: Ia203d3f891c30fd95d0103489056fe01d63a2899
Reviewed-on: https://go-review.googlesource.com/c/go/+/302809
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
This CL adds rewrite rules for CSETM, CSINC, CSINV, and CSNEG. By adding
these rules, we can save one instruction.
For example,
func test(cond bool, a int) int {
if cond {
a++
}
return a
}
Before:
MOVD "".a+8(RSP), R0
ADD $1, R0, R1
MOVBU "".cond(RSP), R2
CMPW $0, R2
CSEL NE, R1, R0, R0
After:
MOVBU "".cond(RSP), R0
CMPW $0, R0
MOVD "".a+8(RSP), R0
CSINC EQ, R0, R0, R0
This patch is a copy of CL 285694. Co-authored-by: JunchenLi
<junchen.li@arm.com>
Change-Id: Ic1a79e8b8ece409b533becfcb7950f11e7b76f24
Reviewed-on: https://go-review.googlesource.com/c/go/+/302231
Trust: fannie zhang <Fannie.Zhang@arm.com>
Run-TryBot: fannie zhang <Fannie.Zhang@arm.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This CL resurrects the clobberdead debugging mode (CL 23924).
When -clobberdead flag is set (TODO: make it GOEXPERIMENT?), the
compiler inserts code that clobbers all dead stack slots that
contains pointers.
Mark windows syscall functions cgo_unsafe_args, as the code
actually does that, by taking the address of one argument and
passing it to cgocall.
Change-Id: Ie09a015f4bd14ae6053cc707866e30ae509b9d6f
Reviewed-on: https://go-review.googlesource.com/c/go/+/301791
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
These instructions are actually 5 argument opcodes as specified
by the ISA. Prior to this patch, the MB and ME arguments were
merged into a single bitmask operand to workaround the limitations
of the ppc64 assembler backend.
This limitation no longer exists. Thus, we can pass operands for
these opcodes without having to merge the MB and ME arguments in
the assembler frontend or compiler backend.
Likewise, support for 4 operand variants is unchanged.
Change-Id: Ib086774f3581edeaadfd2190d652aaaa8a90daeb
Reviewed-on: https://go-review.googlesource.com/c/go/+/298750
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Carlos Eduardo Seo <carlos.seo@linaro.org>
Trust: Carlos Eduardo Seo <carlos.seo@linaro.org>
