If we're not using the upper bits, don't bother issuing a
sign/zero extension operation.
For arm64, after CL 520916 which fixed a correctness bug with
extensions but as a side effect leaves many unnecessary ones
still in place.
Change-Id: I5f4fe4efbf2e9f80969ab5b9a6122fb812dc2ec0
Reviewed-on: https://go-review.googlesource.com/c/go/+/521496
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Reviewed-by: Keith Randall <khr@google.com>
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This CL implements the remainder of the zero-copy string->[]byte
conversion optimization initially attempted in go.dev/cl/520395, but
fixes the tracking of mutations due to ODEREF/ODOTPTR assignments, and
adds more comprehensive tests that I should have included originally.
However, this CL also keeps it behind the -d=zerocopy flag. The next
CL will enable it by default (for easier rollback).
Updates #2205.
Change-Id: Ic330260099ead27fc00e2680a59c6ff23cb63c2b
Reviewed-on: https://go-review.googlesource.com/c/go/+/520599
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This reverts CL 520395.
Reason for revert: thanm@ pointed out failure cases.
Change-Id: I3fd60b73118be3652be2c08b77ab39e793b42110
Reviewed-on: https://go-review.googlesource.com/c/go/+/520596
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
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This CL enables the latent support for string->[]byte conversions
added go.dev/cl/520259.
One catch is that we need to make sure []byte("") evaluates to a
non-nil slice, even if "" is (nil, 0). This CL addresses that by
adding a "ptr != nil" check for OSTR2BYTESTMP, unless the NonNil flag
is set.
The existing uses of OSTR2BYTESTMP (which aren't concerned about
[]byte("") evaluating to nil) are updated to set this flag.
Fixes#2205.
Change-Id: I35a9cb16c164cd86156b7560915aba5108d8b523
Reviewed-on: https://go-review.googlesource.com/c/go/+/520395
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Currently, we rewrite:
go f(new(T))
into:
tmp := new(T)
go func() { f(tmp) }()
However, we can both shrink the closure and improve escape analysis by
instead rewriting it into:
go func() { f(new(T)) }()
This CL does that.
Change-Id: Iae16a476368da35123052ca9ff41c49159980458
Reviewed-on: https://go-review.googlesource.com/c/go/+/520340
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Normalizing go/defer statements to always use functions with zero
parameters and zero results was added to escape analysis, because that
was the earliest point at which all three frontends converged. Now
that we only have the unified frontend, we can do it during typecheck,
which is where we perform all other desugaring and normalization
rewrites.
Change-Id: Iebf7679b117fd78b1dffee2974bbf85ebc923b23
Reviewed-on: https://go-review.googlesource.com/c/go/+/520260
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I previously used a clumsy hack to copy Closgen back and forth while
inlining, to handle when an inlined function contains closures, which
need to each be uniquely numbered.
The real solution was to name the closures using r.inlCaller, rather
than r.curfn. This CL adds a helper method to do exactly this.
Change-Id: I510553b5d7a8f6581ea1d21604e834fd6338cb06
Reviewed-on: https://go-review.googlesource.com/c/go/+/520339
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This CL extends escape analysis in two ways.
First, we already optimize directly called closures. For example,
given:
var x int // already stack allocated today
p := func() *int { return &x }()
we don't need to move x to the heap, because we can statically track
where &x flows. This CL extends the same idea to work for indirectly
called closures too, as long as we know everywhere that they're
called. For example:
var x int // stack allocated after this CL
f := func() *int { return &x }
p := f()
This will allow a subsequent CL to move the generation of go/defer
wrappers earlier.
Second, this CL adds tracking to detect when pointer values flow to
the pointee operand of an indirect assignment statement (i.e., flows
to p in "*p = x") or to builtins that modify memory (append, copy,
clear). This isn't utilized in the current CL, but a subsequent CL
will make use of it to better optimize string->[]byte conversions.
Updates #2205.
Change-Id: I610f9c531e135129c947684833e288ce64406f35
Reviewed-on: https://go-review.googlesource.com/c/go/+/520259
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For aggregate-typed arguments passed to a call, expandCalls
decomposed them into parts in the same block where the value
was created. This is not necessarily the call block, and in
the case where stores are involved, can change the memory
leaving that block, and getting that right is problematic.
Instead, do all the expanding in the same block as the call,
which avoids the problems of (1) not being able to reorder
loads/stores across a block boundary to conform to memory
order and (2) (incorrectly, not) exposing the new memory to
consumers in other blocks. Putting it all in the same block
as the call allows reordering, and the call creates its own
new memory (which is already dealt with correctly).
Fixes#61992.
Change-Id: Icc7918f0d2dd3c480cc7f496cdcd78edeca7f297
Reviewed-on: https://go-review.googlesource.com/c/go/+/519276
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Open-coded defer slots are assigned indices upfront, so they're
logically like elements in an array. Without reassigning the indices,
we need to keep all of the elements alive so their relative offsets
are correct.
Fixes#61895.
Change-Id: Ie0191fdb33276f4e8ed0becb69086524fff022b2
Reviewed-on: https://go-review.googlesource.com/c/go/+/517856
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CL 497276 added optimization for len(string([]byte)) by avoiding call to
slicebytetostring. However, the bytes to string expression may contain
init nodes, which need to be preserved. Otherwise, it would make the
liveness analysis confusing about the lifetime of temporary variables
created by init nodes.
Fixes#61778
Change-Id: I6d1280a7d61bcc75f11132af41bda086f084ab54
Reviewed-on: https://go-review.googlesource.com/c/go/+/516375
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Stop using BTSconst and friends when ORLconst can be used instead.
OR can be issued by more function units than BTS can, so it could
lead to better IPC. OR might take a few more bytes to encode, but
not a lot more.
Still use BTSconst for cases where the constant otherwise wouldn't
fit and would require a separate movabs instruction to materialize
the constant. This happens when setting bits 31-63 of 64-bit targets.
Add BTS-to-memory operations so we don't need to load/bts/store.
Fixes#61694
Change-Id: I00379608df8fb0167cb01466e97d11dec7c1596c
Reviewed-on: https://go-review.googlesource.com/c/go/+/515755
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Fixes#61629
This reduce the pressure on regalloc because then the loop only keep alive
one value (the iterator) instead of the iterator and the upper bound since
the comparison now acts against an immediate, often zero which can be skipped.
This optimize things like:
for i := 0; i < n; i++ {
Or a range over a slice where the index is not used:
for _, v := range someSlice {
Or the new range over int from #61405:
for range n {
It is hit in 975 unique places while doing ./make.bash.
Change-Id: I5facff8b267a0b60ea3c1b9a58c4d74cdb38f03f
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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
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If we load 2 values and then store those 2 loaded values, we can likely
perform that operation with a single wider load and store.
Fixes#60709
Change-Id: Ifc5f92c2f1b174c6ed82a69070f16cec6853c770
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The compiler/assembler's -S output prints relocation type
numerically, which is hard to understand. Every time I need to
count the relocation type constants to figure out which relocation
it actually is. Print the symbolic name instead.
Change-Id: I4866873bbae8b3dc0ee212609cb00280f9164243
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(ANDCCconst [y] (MOV.*reg x)) should only be merged when zero
extending. Otherwise, sign bits are lost on negative values.
(ANDCCconst [0xFF] (MOVBreg x)) should be simplified to a zero
extension of x. Likewise for the MOVHreg variant.
Fixes#61297
Change-Id: I04e4fd7dc6a826e870681f37506620d48393698b
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User code is unlikely to be correct, but don't crash the compiler
when the offset of a pointer in an object is not a multiple of the
pointer size.
Fixes#61187
Change-Id: Ie56bfcb38556c5dd6f702ae4ec1d4534c6acd420
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According to RISCV manual 11.6:
FMADD x,y,z computes x*y+z and
FNMADD x,y,z => -x*y-z
FMSUB x,y,z => x*y-z
FNMSUB x,y,z => -x*y+z respectively
However our implement of SSA convert FMADD -x,y,z to FNMADD x,y,z which
is wrong and should be convert to FNMSUB according to manual.
Change-Id: Ib297bc83824e121fd7dda171ed56ea9694a4e575
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The large-function phi placement algorithm evidently doesn't like the
same pseudo-variable being used to represent expressions of varying
types.
Instead, use the same tactic as used for "valVar" (ssa.go:6585--6587),
which is to just generate a fresh marker node each time.
Maybe we could just use the OMIN/OMAX nodes themselves as the key
(like we do for OANDAND/OOROR), but that just seems needlessly risky
for negligible memory savings. Using fresh marker values each time
seems obviously safe by comparison.
Fixes#61041.
Change-Id: Ie2600c9c37b599c2e26ae01f5f8a433025d7fd08
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For float or string, min/max builtin performs a runtime call, so we need
to save its result to temporary variable. Otherwise, the runtime call
will clobber closure's arguments currently on the stack when passing
min/max as argument to closures.
Fixes#60990
Change-Id: I1397800f815ec7853182868678d0f760b22afff2
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Our large-function phi placement algorithm is incompatible with phi
opcodes already existing in the SSA representation. Instead, use simple
variable assignments and have the phi placement algorithm place the phis
we need for min/max.
Turns out the small-function phi placement algorithm doesn't have this
sensitivity, so this bug only occurs in large functions (>500 basic blocks).
Maybe we should document/check that no phis are present when we start
phi placement (regardless of size). Leaving for a potential separate CL.
We should probably also fix the placement algorithm to handle existing
phis correctly. But this CL is probably a lot smaller/safer than
messing with phi placement.
Fixes#60982
Change-Id: I59ba7f506c72b22bc1485099a335d96315ebef67
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CL 410344 fixed missing method value wrapper, by visiting body of
wrapper function after applying inlining pass.
CL 492017 allow more inlining of functions that construct closures,
which ends up making the wrapper function now inlineable, but can
contain closure nodes that couldn't be inlined. These closures body may
contain OMETHVALUE nodes that we never seen, thus we need to scan
closures body for finding them.
Fixes#60945
Change-Id: Ia1e31420bb172ff87d7321d2da2989ef23e6ebb6
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Change-Id: Idd872c5b90dbca564ed8a37bb3683e642142ae63
Reviewed-on: https://go-review.googlesource.com/c/go/+/505015
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Currently ArenaNew expects the type passed in to be a *T and it returns
a *T. This does not match the function's documentation.
Since this is an experiment, change ArenaNew to match the documentation.
This more closely aligns ArenaNew with arena.New. (Takes a type T,
returns a *T value.)
Note that this is a breaking change. However, as far as pkg.go.dev can
tell, there's exactly one package using it in the open source world.
Also, add smoke test for the exported API, which is just a wrapper
around the internal API. Clearly there's enough room for error here that
it should be tested, but we don't need thorough tests at this layer
because that already exists in the runtime. We just need to make sure it
basically works.
Fixes#60528.
Change-Id: I673cc4609378380ef80648b0c2eb2928e73f49c9
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types2 have already errored about any spec-required overflows, and
division by zero. CL 469595 unintentionally fixed typecheck not to error
about overflows, but zero division is still be checked during tcArith.
This causes unsafe operations with variable size failed to compile,
instead of raising runtime error.
Fixes#60601
Change-Id: I7bea2821099556835c920713397f7c5d8a4025ac
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Don't use the line number of the argument itself, as that may be from
arbitrarily earlier in the function.
Fixes#60673
Change-Id: Ifc0a2aaae221a256be3a4b0b2e04849bae4b79d7
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CL 496257 adds min/max builtins, which may appear as argument to a
function call, so it will be tested by mayCall. But those ops are not
handled by mayCall, causes the compiler crashes.
Fixes#60582
Change-Id: I729f10bf62b4aad39ffcb1433f576e74d09fdd9a
Reviewed-on: https://go-review.googlesource.com/c/go/+/500575
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HAUTO should be handled the same way as other stack offsets for
adding to constant pool. Add the missing cases.
Fixes#57955.
Change-Id: If7fc82cafb2bbf0a6121e73e353b8825cb36b5bc
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Some testdir tests fail if GOEXPERIMENT=cgocheck2 is set. Fix this by
skipping these tests.
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Two interface types that are assignable don't have to be identical;
specifically, if they are defined types, they can be different
defined types. If those defined types specify type parameters which
are never used, do not infer a type argument based on the instantiation
of a matching defined type.
Adjusted three existing tests where we inferred type arguments incorrectly.
Fixes#60377.
Change-Id: I91fb207235424b3cbc42b5fd93eee619e7541cb7
Reviewed-on: https://go-review.googlesource.com/c/go/+/498315
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sparse conditional constant propagation can discover optimization opportunities that cannot be found by just combining constant folding and constant propagation and dead code elimination separately.
Updates #59399
Change-Id: Ia954e906480654a6f0cc065d75b5912f96f36b2e
GitHub-Last-Rev: 90fc02db99
GitHub-Pull-Request: golang/go#59575
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CL 415241 and CL 411935 break tests into unified/nounified variants, for
compatibility with old frontend while developing unified IR. Now the old
frontend was gone, so moving those tests back to the original files.
Change-Id: Iecdcd4e6ee33c723f6ac02189b0be26248e15f0f
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In Go 1.17, cmd/compile gained the ability to inline calls to
functions that contain function literals (aka "closures"). This was
implemented by duplicating the function literal body and emitting a
second LSym, because in general it might be optimized better than the
original function literal.
However, the second LSym was named simply as any other function
literal appearing literally in the enclosing function would be named.
E.g., if f has a closure "f.funcX", and f is inlined into g, we would
create "g.funcY" (N.B., X and Y need not be the same.). Users then
have no idea this function originally came from f.
With this CL, the inlined call stack is incorporated into the clone
LSym's name: instead of "g.funcY", it's named "g.f.funcY".
In the future, it seems desirable to arrange for the clone's name to
appear exactly as the original name, so stack traces remain the same
as when -l or -d=inlfuncswithclosures are used. But it's unclear
whether the linker supports that today, or whether any downstream
tooling would be confused by this.
Updates #60324.
Change-Id: Ifad0ccef7e959e72005beeecdfffd872f63982f8
Reviewed-on: https://go-review.googlesource.com/c/go/+/497137
Reviewed-by: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
