Optimize comparisons with constants that only differ by 1 bit (i.e.
a power of 2). For example:
x == 4 || x == 6 -> x|2 == 6
x != 1 && x != 5 -> x|4 != 5
Change-Id: Ic61719e5118446d21cf15652d9da22f7d95b2a15
Reviewed-on: https://go-review.googlesource.com/c/go/+/719420
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This CL implements Mul64uhilo, Hmul64, Hmul64u, and Avg64u
on 32-bit systems, with the effect that constant division of both
int64s and uint64s can now be emitted directly in all cases,
and also that bits.Mul64 can be intrinsified on 32-bit systems.
Previously, constant division of uint64s by values 0 ≤ c ≤ 0xFFFF were
implemented as uint32 divisions by c and some fixup. After expanding
those smaller constant divisions, the code for i/999 required:
(386) 7 mul, 10 add, 2 sub, 3 rotate, 3 shift (104 bytes)
(arm) 7 mul, 9 add, 3 sub, 2 shift (104 bytes)
(mips) 7 mul, 10 add, 5 sub, 6 shift, 3 sgtu (176 bytes)
For that much code, we might as well use a full 64x64->128 multiply
that can be used for all divisors, not just small ones.
Having done that, the same i/999 now generates:
(386) 4 mul, 9 add, 2 sub, 2 or, 6 shift (112 bytes)
(arm) 4 mul, 8 add, 2 sub, 2 or, 3 shift (92 bytes)
(mips) 4 mul, 11 add, 3 sub, 6 shift, 8 sgtu, 4 or (196 bytes)
The size increase on 386 is due to a few extra register spills.
The size increase on mips is due to add-with-carry being hard.
The new approach is more general, letting us delete the old special case
and guarantee that all int64 and uint64 divisions by constants are
generated directly on 32-bit systems.
This especially speeds up code making heavy use of bits.Mul64 with
a constant argument, which happens in strconv and various crypto
packages. A few examples are benchmarked below.
pkg: cmd/compile/internal/test
benchmark \ host local linux-amd64 s7 linux-386 s7:GOARCH=386
vs base vs base vs base vs base vs base
DivconstI64 ~ ~ ~ -49.66% -21.02%
ModconstI64 ~ ~ ~ -13.45% +14.52%
DivisiblePow2constI64 ~ ~ ~ +0.97% -1.32%
DivisibleconstI64 ~ ~ ~ -20.01% -48.28%
DivisibleWDivconstI64 ~ ~ -1.76% -38.59% -42.74%
DivconstU64/3 ~ ~ ~ -13.82% -4.09%
DivconstU64/5 ~ ~ ~ -14.10% -3.54%
DivconstU64/37 -2.07% -4.45% ~ -19.60% -9.55%
DivconstU64/1234567 ~ ~ ~ -61.55% -56.93%
ModconstU64 ~ ~ ~ -6.25% ~
DivisibleconstU64 ~ ~ ~ -2.78% -7.82%
DivisibleWDivconstU64 ~ ~ ~ +4.23% +2.56%
pkg: math/bits
benchmark \ host s7 linux-amd64 linux-386 s7:GOARCH=386
vs base vs base vs base vs base
Add ~ ~ ~ ~
Add32 +1.59% ~ ~ ~
Add64 ~ ~ ~ ~
Add64multiple ~ ~ ~ ~
Sub ~ ~ ~ ~
Sub32 ~ ~ ~ ~
Sub64 ~ ~ -9.20% ~
Sub64multiple ~ ~ ~ ~
Mul ~ ~ ~ ~
Mul32 ~ ~ ~ ~
Mul64 ~ ~ -41.58% -53.21%
Div ~ ~ ~ ~
Div32 ~ ~ ~ ~
Div64 ~ ~ ~ ~
pkg: strconv
benchmark \ host s7 linux-amd64 linux-386 s7:GOARCH=386
vs base vs base vs base vs base
ParseInt/Pos/7bit ~ ~ -11.08% -6.75%
ParseInt/Pos/26bit ~ ~ -13.65% -11.02%
ParseInt/Pos/31bit ~ ~ -14.65% -9.71%
ParseInt/Pos/56bit -1.80% ~ -17.97% -10.78%
ParseInt/Pos/63bit ~ ~ -13.85% -9.63%
ParseInt/Neg/7bit ~ ~ -12.14% -7.26%
ParseInt/Neg/26bit ~ ~ -14.18% -9.81%
ParseInt/Neg/31bit ~ ~ -14.51% -9.02%
ParseInt/Neg/56bit ~ ~ -15.79% -9.79%
ParseInt/Neg/63bit ~ ~ -15.68% -11.07%
AppendFloat/Decimal ~ ~ -7.25% -12.26%
AppendFloat/Float ~ ~ -15.96% -19.45%
AppendFloat/Exp ~ ~ -13.96% -17.76%
AppendFloat/NegExp ~ ~ -14.89% -20.27%
AppendFloat/LongExp ~ ~ -12.68% -17.97%
AppendFloat/Big ~ ~ -11.10% -16.64%
AppendFloat/BinaryExp ~ ~ ~ ~
AppendFloat/32Integer ~ ~ -10.05% -10.91%
AppendFloat/32ExactFraction ~ ~ -8.93% -13.00%
AppendFloat/32Point ~ ~ -10.36% -14.89%
AppendFloat/32Exp ~ ~ -9.88% -13.54%
AppendFloat/32NegExp ~ ~ -10.16% -14.26%
AppendFloat/32Shortest ~ ~ -11.39% -14.96%
AppendFloat/32Fixed8Hard ~ ~ ~ -2.31%
AppendFloat/32Fixed9Hard ~ ~ ~ -7.01%
AppendFloat/64Fixed1 ~ ~ -2.83% -8.23%
AppendFloat/64Fixed2 ~ ~ ~ -7.94%
AppendFloat/64Fixed3 ~ ~ -4.07% -7.22%
AppendFloat/64Fixed4 ~ ~ -7.24% -7.62%
AppendFloat/64Fixed12 ~ ~ -6.57% -4.82%
AppendFloat/64Fixed16 ~ ~ -4.00% -5.81%
AppendFloat/64Fixed12Hard -2.22% ~ -4.07% -6.35%
AppendFloat/64Fixed17Hard -2.12% ~ ~ -3.79%
AppendFloat/64Fixed18Hard -1.89% ~ +2.48% ~
AppendFloat/Slowpath64 -1.85% ~ -14.49% -18.21%
AppendFloat/SlowpathDenormal64 ~ ~ -13.08% -19.41%
pkg: crypto/internal/fips140/nistec/fiat
benchmark \ host s7 linux-amd64 linux-386 s7:GOARCH=386
vs base vs base vs base vs base
Mul/P224 ~ ~ -29.95% -39.60%
Mul/P384 ~ ~ -37.11% -63.33%
Mul/P521 ~ ~ -26.62% -12.42%
Square/P224 +1.46% ~ -40.62% -49.18%
Square/P384 ~ ~ -45.51% -69.68%
Square/P521 +90.37% ~ -25.26% -11.23%
(The +90% is a separate problem and not real; that much variation
can be seen on that system by running the same binary from two
different files.)
pkg: crypto/internal/fips140/edwards25519
benchmark \ host s7 linux-amd64 linux-386 s7:GOARCH=386
vs base vs base vs base vs base
EncodingDecoding ~ ~ -34.67% -35.75%
ScalarBaseMult ~ ~ -31.25% -30.29%
ScalarMult ~ ~ -33.45% -32.54%
VarTimeDoubleScalarBaseMult ~ ~ -33.78% -33.68%
Change-Id: Id3c91d42cd01def6731b755e99f8f40c6ad1bb65
Reviewed-on: https://go-review.googlesource.com/c/go/+/716061
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Now that it also restricts to comparable types. Followon to CL 713840.
Change-Id: Idd975c3fd16fb51f55360f2fa0b89ab0bf1d00ed
Reviewed-on: https://go-review.googlesource.com/c/go/+/715700
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Leave those constant foldings for runtime, similar to how we do it
for NaN generation.
These are the only instances I could find in cmd/compile/..., using
objdump -d ../pkg/tool/darwin_arm64/compile| egrep "(fcvtz|>:)" | grep -B1 fcvt
(There are instances in other places, like runtime and reflect, but I don't
think those places would affect compiler output.)
Change-Id: I4113fe4570115e4765825cf442cb1fde97cf2f27
Reviewed-on: https://go-review.googlesource.com/c/go/+/711281
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This change creates calls to size-specialized malloc functions instead
of calls to newObject when we know the size of the allocation at
compilation time. Most of it is a matter of calling the newObject
function (which will create calls to the size-specialized functions)
rather then the newObjectNonSpecialized function (which won't). In the
newHeapaddr, small, non-pointer case, we'll create a non specialized
newObject and transform that into the appropriate size-specialized
function when we produce the mallocgc in flushPendingHeapAllocations.
We have to update some of the rewrites in generic.rules to also apply to
the size-specialized functions when they apply to newObject.
The messiest thing is we have to adjust the offset we use to save the
memory profiler stack, because the depth of the call to profilealloc is
two frames fewer in the size-specialized malloc functions compared to
when newObject calls mallocgc. A bunch of tests have been adjusted to
account for that.
Change-Id: I6a6a6964c9037fb6719e392c4a498ed700b617d7
Reviewed-on: https://go-review.googlesource.com/c/go/+/707856
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This might have been something that prove could be educated
into figuring out, but this also works, and it also helps
prove downstream.
Adjusted the prove test, because this change moved a message.
Cherry-picked from the dev.simd branch. This CL is not
necessarily SIMD specific. Apply early to reduce risk.
Change-Id: I5eabe639eff5db9cd9766a6a8666fdb4973829cb
Reviewed-on: https://go-review.googlesource.com/c/go/+/697715
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Many CLs have worked with this bit of code, extending the cases more and
more for various fixed addresses and constants. But, I find that it's
getting duplicitive, and I don't find the current setup very clear that
something like isFixed32 _only_ works for a specific element within the
type data.
This CL rewrites these rules (pun unintended) into a single set of
rewrite rules with shared logic, which stops hardcoding offsets and type
compatibility checks.
This should open the door to optimizing further type:... field loads, of
which most can be done entirely statically but are not yet today outside
Hash and Elem.
Passes toolstash -cmp.
Change-Id: I754138ce1785c6036eada9ed53f0ce2ad2a58b63
Reviewed-on: https://go-review.googlesource.com/c/go/+/701297
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CL 700336 let the compiler see into the abi.PtrType.Elem field,
but forgot the MarkTypeSymUsedInInterface to ensure that the symbol
is marked as referenced.
I am not sure how to write a test for this, but I noticed this when
working on further optimizations where I "fixed" this issue and
confusingly failed toolstash -cmp, with diffs like:
@@ -70582,6 +70582,7 @@ reflect.groupAndSlotOf<1> STEXT size=696 args=0x20 locals=0x1e0 funcid=0x0 align
rel 3+0 t=R_USEIFACE type:*reflect.rtype<0>+0
rel 3+0 t=R_USEIFACE type:*reflect.rtype<0>+0
rel 3+0 t=R_USEIFACE type:*uint64<0>+0
+ rel 3+0 t=R_USEIFACE type:uint64<0>+0
rel 71+0 t=R_CALLIND +0
rel 92+4 t=R_PCREL go:itab.*reflect.rtype,reflect.Type<0>+0
rel 114+4 t=R_CALL reflect.(*rtype).ptrTo<1>+0
Updates #75203
Change-Id: Ib8de8a32aeb8a7ea6fcf5d728a2e4944ef227ab2
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This CL makes the generated code for reflect.TypeFor as simple as an
intrinsic function.
Fixes#75203
Change-Id: I7bb48787101f07e77ab5c583292e834c28a028d6
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Allows rewrite rules using oneBit to be made more compact.
Change-Id: I986715f77db5b548759d809fe668e1893048f25c
Reviewed-on: https://go-review.googlesource.com/c/go/+/699295
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This reverts commit cd55f86b8d (CL 681937)
Reason for revert: still causing compiler failures on Google test code
Change-Id: I5cd482fd607fd060a523257082d48821b5f965d6
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This reverts commit 72e8237cc1 (CL 693615)
Reason for revert: still causing compiler failures on Google test code
Change-Id: I4a7850c321d95ed7803d56866bb0c524c7a377d3
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imakeOfStructMake does the right thing, but we never call it
when the StructMake has more than one argument.
Fixes#74908
Change-Id: Ib4b1a025bfb1fa69a325207e47b74bd6217092bf
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If the struct is a bunch of 0-sized fields and one pointer field.
Fixes#74092
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Same as CL 689815, but for modulus instead of division.
Updates #74485
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Change-Id: I7b8e8cd88c4d6d562aa25df91593d35d331ef63c
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I don't think branchelim will intentionally generate theses.
But at the time where branchelim is generating them they might different,
and through opt process they become the same value.
Change-Id: I4a19f1db14c08057b7e782a098f4c18ca36ab7fe
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For performance see CL 685676.
This allows something like:
if y { x *= 2 }
To be compiled to:
SHLXQ BX, AX, AX
Instead of:
MOVQ AX, CX
SHLQ $1, CX
MOVBLZX BL, DX
TESTQ DX, DX
CMOVQNE CX, AX
While ./make.bash uniqued per LOC, there is 2 doublings and 4 halvings.
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This allows something like:
if y { x++ }
To be compiled to:
MOVBLZX BX, CX
ADDQ CX, AX
Instead of:
LEAQ 1(AX), CX
MOVBLZX BL, DX
TESTQ DX, DX
CMOVQNE CX, AX
While ./make.bash uniqued per LOC, there is 100 additions and 75 substractions.
See benchmark here: https://go.dev/play/p/DJf5COjwhd_s
Either it's a performance no-op or it is faster:
goos: linux
goarch: amd64
cpu: AMD Ryzen 5 3600 6-Core Processor
│ /tmp/old.logs │ /tmp/new.logs │
│ sec/op │ sec/op vs base │
CmovInlineConditionAddLatency-12 0.5443n ± 5% 0.5339n ± 3% -1.90% (p=0.004 n=10)
CmovInlineConditionAddThroughputBy6-12 1.492n ± 1% 1.494n ± 1% ~ (p=0.955 n=10)
CmovInlineConditionSubLatency-12 0.5419n ± 3% 0.5282n ± 3% -2.52% (p=0.019 n=10)
CmovInlineConditionSubThroughputBy6-12 1.587n ± 1% 1.584n ± 2% ~ (p=0.492 n=10)
CmovOutlineConditionAddLatency-12 0.5223n ± 1% 0.2639n ± 4% -49.47% (p=0.000 n=10)
CmovOutlineConditionAddThroughputBy6-12 1.159n ± 1% 1.097n ± 2% -5.35% (p=0.000 n=10)
CmovOutlineConditionSubLatency-12 0.5271n ± 3% 0.2654n ± 2% -49.66% (p=0.000 n=10)
CmovOutlineConditionSubThroughputBy6-12 1.053n ± 1% 1.050n ± 1% ~ (p=1.000 n=10)
geomean
There are other benefits not tested by this benchmark:
- the math form is usually a couple bytes shorter (ICACHE)
- the math form is usually 0~2 uops shorter (UCACHE)
- the math form has usually less register pressure*
- the math form can sometimes be optimized further
*regalloc rarely find how it can use less registers
As far as pass ordering goes there are many possible options,
I've decided to reorder branchelim before late opt since:
- unlike running exclusively the CondSelect rules after branchelim,
some extra optimizations might trigger on the adds or subs.
- I don't want to maintain a second generic.rules file of only the stuff,
that can trigger after branchelim.
- rerunning all of opt a third time increase compilation time for little gains.
By elimination moving branchelim seems fine.
Change-Id: I869adf57e4d109948ee157cfc47144445146bafd
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unique.Make always copies strings passed into it, so it's safe to not
copy byte slices converted to strings either. Handle this just like map
accesses with string(b) as keys.
This CL only handles unique.Make(string(b)), not nested cases like
unique.Make([2]string{string(b1), string(b2)}); this could be done in a
followup CL but the map lookup code in walk is sufficiently different
than the call handling code that I didn't attempt it. (SSA is much
easier).
Fixes#71926
Change-Id: Ic2f82f2f91963d563b4ddb1282bd49fc40da8b85
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The full 64x64->128 multiply comes up when using bits.Mul64.
The 64x64->64+overflow multiply comes up in unsafe.Slice when using
a constant length.
Change-Id: I298515162ca07d804b2d699d03bc957ca30a4ebc
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Improve the compiler's store-to-load forwarding optimization by relaxing the
type comparison condition. Instead of requiring exact type equality (CMPeq),
we now use copyCompatibleType which allows forwarding between compatible
types where safe.
Fix several size comparison bugs in the nested store patterns. Previously,
we were comparing the size of the outer store with the load type,
rather than comparing with the size of the actual store being forwarded
from.
Skip OpConvert in dead store elimination to help get rid of dead stores such
as zeroing slices. OpConvert, like OpInlMark, doesn't really use the memory.
This optimization is particularly beneficial for code that creates slices with
computed pointers, such as the runtime's heapBitsSlice function, where
intermediate calculations were previously causing the compiler to miss
store-to-load forwarding opportunities.
Local sweet run result on an x86_64 laptop:
│ Orig.res │ Hopt.res │
│ sec/op │ sec/op vs base │
BiogoIgor-8 5.303 ± 1% 5.322 ± 1% ~ (p=0.190 n=10)
BiogoKrishna-8 7.894 ± 1% 7.828 ± 2% ~ (p=0.190 n=10)
BleveIndexBatch100-8 2.257 ± 1% 2.248 ± 2% ~ (p=0.529 n=10)
EtcdPut-8 30.12m ± 1% 30.03m ± 1% ~ (p=0.796 n=10)
EtcdSTM-8 127.1m ± 1% 126.2m ± 0% -0.74% (p=0.023 n=10)
GoBuildKubelet-8 52.21 ± 0% 52.05 ± 1% ~ (p=0.063 n=10)
GoBuildKubeletLink-8 4.342 ± 1% 4.305 ± 0% -0.85% (p=0.000 n=10)
GoBuildIstioctl-8 43.33 ± 0% 43.24 ± 0% -0.22% (p=0.015 n=10)
GoBuildIstioctlLink-8 4.604 ± 1% 4.598 ± 0% ~ (p=0.063 n=10)
GoBuildFrontend-8 15.33 ± 0% 15.29 ± 0% ~ (p=0.143 n=10)
GoBuildFrontendLink-8 740.0m ± 1% 737.7m ± 1% ~ (p=0.912 n=10)
GopherLuaKNucleotide-8 9.590 ± 1% 9.656 ± 1% ~ (p=0.165 n=10)
MarkdownRenderXHTML-8 96.97m ± 1% 97.26m ± 2% ~ (p=0.105 n=10)
Tile38QueryLoad-8 335.9µ ± 1% 335.6µ ± 1% ~ (p=0.481 n=10)
geomean 1.336 1.333 -0.22%
Change-Id: I031552623e6d5a3b1b5be8325e6314706e45534f
Reviewed-on: https://go-review.googlesource.com/c/go/+/662075
Reviewed-by: Carlos Amedee <carlos@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Carlos Amedee <carlos@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
While looking at the SSA of following code, i noticed
that these rules do not work properly, and the types
are loaded indirectly through an itab, instead of statically.
type M interface{ M() }
type A interface{ A() }
type Impl struct{}
func (*Impl) M() {}
func (*Impl) A() {}
func main() {
var a M = &Impl{}
a.(A).A()
}
Change-Id: Ia275993f81a2e7302102d4ff87ac28586023d13c
GitHub-Last-Rev: 4bfc901917
GitHub-Pull-Request: golang/go#71784
Reviewed-on: https://go-review.googlesource.com/c/go/+/649500
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
If we call slicebytetostring immediately (with no intervening writes)
before calling map access or delete functions with the resulting
string as the key, then we can just use the ptr/len of the
slicebytetostring argument as the key. This avoids an allocation.
Fixes#44898
Update #71132
There's old code in cmd/compile/internal/walk/order.go that handles
some of these cases.
1. m[string(b)]
2. s := string(b); m[s]
3. m[[2]string{string(b1),string(b2)}]
The old code handled cases 1&3. The new code handles cases 1&2.
We'll leave the old code around to keep 3 working, although it seems
not terribly common.
Case 2 happens particularly after inlining, so it is pretty common.
Change-Id: I8913226ca79d2c65f4e2bd69a38ac8c976a57e43
Reviewed-on: https://go-review.googlesource.com/c/go/+/640656
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
We can just use == if the interface is direct.
Fixes#70738
Change-Id: Ia9a644791a370fec969c04c42d28a9b58f16911f
Reviewed-on: https://go-review.googlesource.com/c/go/+/635435
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
This came up in some swissmap code.
Change-Id: I3c6705a5cafec8cb4953dfa9535cf0b45255cc83
Reviewed-on: https://go-review.googlesource.com/c/go/+/629516
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: David Chase <drchase@google.com>
Optimize them away if we can.
If not, be more careful about splicing them out after scheduling.
Change-Id: I660e54649d753dc456d2e25d389d375a16d76940
Reviewed-on: https://go-review.googlesource.com/c/go/+/627418
Reviewed-by: Shengwei Zhao <wingrez@126.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Fixes#69635
Change-Id: I4f8d7dafb34ccfb943c29f96c982278ab7edcd05
Reviewed-on: https://go-review.googlesource.com/c/go/+/621357
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
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Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
The SSA backend currently only handle struct with up to 4 fields. Thus,
there are different operations corresponding to number fields of the
struct.
This CL generalizes these with just one OpStructMake, allow struct types
with arbitrary number of fields.
However, the ssa.MaxStruct is still kept as-is, and future CL will
increase this value to optimize large structs.
Updates #24416
Change-Id: I192ffbea881186693584476b5639394e79be45c5
Reviewed-on: https://go-review.googlesource.com/c/go/+/611075
Reviewed-by: Keith Randall <khr@golang.org>
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Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: David Chase <drchase@google.com>
Change-Id: I50a19bd971176598bf8e4ef86ec98f008abe245c
Reviewed-on: https://go-review.googlesource.com/c/go/+/615198
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
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Auto-Submit: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Change-Id: I097b53e9f13de6ff6eb18ae2261842b097f26390
Reviewed-on: https://go-review.googlesource.com/c/go/+/615197
Auto-Submit: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
Change-Id: I56c27d606b55ea882f4db264fd4735b0cccdf7c6
Reviewed-on: https://go-review.googlesource.com/c/go/+/604015
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
We need to ensure that the Select0 lives in the same block as
its argument. Divide up the rule into 2 so that we can put the
parts in the right places.
(This would be simpler if we could use @block syntax mid-rule, but
that feature currently only works at the top level.)
This fixes the ssacheck builder after CL 578835
Change-Id: Id26a01d9fac0684e0b732d35d0f7999f6de07825
Reviewed-on: https://go-review.googlesource.com/c/go/+/580815
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
The results of cmpstring are reuseable if the second call has the
same arguments and memory.
Note that this gets rid of cmpstring, but we still generate a
redundant </<= test and branch afterwards, because the compiler
doesn't know that cmpstring only ever returns -1,0,1.
Update #61725
Change-Id: I93a0d1ccca50d90b1e1a888240ffb75a3b10b59b
Reviewed-on: https://go-review.googlesource.com/c/go/+/578835
Reviewed-by: David Chase <drchase@google.com>
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Reviewed-by: Cherry Mui <cherryyz@google.com>
This do:
- Fold always false or always true comparisons for ints and uint.
- Reduce < and <= where the true set is only one value to == with such value.
Change-Id: Ie9e3f70efd1845bef62db56543f051a50ad2532e
Reviewed-on: https://go-review.googlesource.com/c/go/+/555135
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Have nil checks return a pointer that is known non-nil. Users of
that pointer can use the result, ensuring that they are ordered
after the nil check itself.
The order dependence goes away after scheduling, when we've fixed
an order. At that point we move uses back to the original pointer
so it doesn't change regalloc any.
This prevents pointer arithmetic on nil from being spilled to the
stack and then observed by a stack scan.
Fixes#63657
Change-Id: I1a5fa4f2e6d9000d672792b4f90dfc1b7b67f6ea
Reviewed-on: https://go-review.googlesource.com/c/go/+/537775
Reviewed-by: David Chase <drchase@google.com>
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Reviewed-by: Keith Randall <khr@google.com>
No need to indirect through Frontend for this.
Change-Id: I5812eb4dadfda79267cabc9d13aeab126c1479e3
Reviewed-on: https://go-review.googlesource.com/c/go/+/526517
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
s==s is always true for strings. This comes up in NaN testing in
generic code, where we want x==x to compile completely away except for
float types.
Fixes#60777
Change-Id: I3ce054b5121354de2f9751b010fb409f148cb637
Reviewed-on: https://go-review.googlesource.com/c/go/+/503795
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
Retrying the original CL with a small modification. The original CL
did not handle the case of reading an itab out of a dictionary
correctly. When we read an itab out of a dictionary, we must treat
the type inside that itab as maybe being put in an interface.
Original CL: 486895
Revert CL: 490156
Change-Id: Id2dc1699d184cd8c63dac83986a70b60b4e6cbd7
Reviewed-on: https://go-review.googlesource.com/c/go/+/491495
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
