Currently, we handle "x op= y" by rewriting as "x = x op y", while
ensuring that any calls or receive operations in 'x' are only
evaluated once. Notably, pointer indirection, indexing operations,
etc. are left alone as it's typically safe to re-evaluate those.
However, those operations were interleaved with evaluating 'y', which
could include function calls that might cause re-evaluation to yield
different memory addresses.
As a fix, simply ensure that we order side-effecting operations in 'y'
before either evaluation of 'x'.
Fixes#21687.
Change-Id: Ib14e77760fda9c828e394e8e362dc9e5319a84b2
Reviewed-on: https://go-review.googlesource.com/60091
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Do the similar thing to CL 55143 to reduce IMUL.
Change-Id: I1bd38f618058e3cd74fac181f003610ea13f2294
Reviewed-on: https://go-review.googlesource.com/56252
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The assembler barfs on large offsets. Make sure that all the
instructions that need to have their offsets in an int32
1) check on any rule that computes offsets for such instructions
2) change their aux fields so the check builder checks it.
The assembler also silently misassembled offsets between 1<<31
and 1<<32. Add a check in the assembler to barf on those as well.
Fixes#21655
Change-Id: Iebf24bf10f9f37b3ea819ceb7d588251c0f46d7d
Reviewed-on: https://go-review.googlesource.com/59630
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
For code like the following (where x escapes):
x := []int{1}
We're currently generating a nil check. The line above is really 3 operations:
t := new([1]int)
t[0] = 1
x := t[:]
We remove the nil check for t[0] = 1, but not for t[:].
Our current nil check removal rule is too strict about the possible
memory arguments of the nil check. Unlike zeroing or storing to the
result of runtime.newobject, the nilness of runtime.newobject is
always false, even after other stores have happened in the meantime.
Change-Id: I95fad4e3a59c27effdb37c43ea215e18f30b1e5f
Reviewed-on: https://go-review.googlesource.com/58711
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This is a crude compiler pass to eliminate stores to auto variables
that are only ever written to.
Eliminates an unnecessary store to x from the following code:
func f() int {
var x := 1
return *(&x)
}
Fixes#19765.
Change-Id: If2c63a8ae67b8c590b6e0cc98a9610939a3eeffa
Reviewed-on: https://go-review.googlesource.com/38746
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Where possible generate calls to runtime makemap with int hint argument
during compile time instead of makemap with int64 hint argument.
This eliminates converting the hint argument for calls to makemap with
int64 hint argument for platforms where int64 values do not fit into
an argument of type int.
A similar optimization for makeslice was introduced in CL
golang.org/cl/27851.
386:
name old time/op new time/op delta
NewEmptyMap 53.5ns ± 5% 41.9ns ± 5% -21.56% (p=0.000 n=10+10)
NewSmallMap 182ns ± 1% 165ns ± 1% -8.92% (p=0.000 n=10+10)
Change-Id: Ibd2b4c57b36f171b173bf7a0602b3a59771e6e44
Reviewed-on: https://go-review.googlesource.com/55142
Reviewed-by: Keith Randall <khr@golang.org>
If an error was already printed during LHS conversion step, we don't reprint
the "cannot convert" error.
In particular, this prevents `_ = int("1")` (and all similar casts) from
resulting in multiple identical error messages being printed.
Fixes#20812.
Change-Id: If6e52c59eab438599d641ecf6f110ebafca740a9
Reviewed-on: https://go-review.googlesource.com/46912
Reviewed-by: Robert Griesemer <gri@golang.org>
There are a few cases where this can be useful. Apart from the obvious
(and silly)
100*n + 200*n
where we generate one IMUL instead of two, consider:
15*n + 31*n
Currently, the compiler strength-reduces both imuls, generating:
0x0000 00000 MOVQ "".n+8(SP), AX
0x0005 00005 MOVQ AX, CX
0x0008 00008 SHLQ $4, AX
0x000c 00012 SUBQ CX, AX
0x000f 00015 MOVQ CX, DX
0x0012 00018 SHLQ $5, CX
0x0016 00022 SUBQ DX, CX
0x0019 00025 ADDQ CX, AX
0x001c 00028 MOVQ AX, "".~r1+16(SP)
0x0021 00033 RET
But combining the imuls is both faster and shorter:
0x0000 00000 MOVQ "".n+8(SP), AX
0x0005 00005 IMULQ $46, AX
0x0009 00009 MOVQ AX, "".~r1+16(SP)
0x000e 00014 RET
even without strength-reduction.
Moreover, consider:
5*n + 7*(n+1) + 11*(n+2)
We already have a rule that rewrites 7(n+1) into 7n+7, so the
generated code (without imuls merging) looks like this:
0x0000 00000 MOVQ "".n+8(SP), AX
0x0005 00005 LEAQ (AX)(AX*4), CX
0x0009 00009 MOVQ AX, DX
0x000c 00012 NEGQ AX
0x000f 00015 LEAQ (AX)(DX*8), AX
0x0013 00019 ADDQ CX, AX
0x0016 00022 LEAQ (DX)(CX*2), CX
0x001a 00026 LEAQ 29(AX)(CX*1), AX
0x001f 00031 MOVQ AX, "".~r1+16(SP)
But with imuls merging, the 5n, 7n and 11n factors get merged, and the
generated code looks like this:
0x0000 00000 MOVQ "".n+8(SP), AX
0x0005 00005 IMULQ $23, AX
0x0009 00009 ADDQ $29, AX
0x000d 00013 MOVQ AX, "".~r1+16(SP)
0x0012 00018 RET
Which is both faster and shorter; that's also the exact same code that
clang and the intel c compiler generate for the above expression.
Change-Id: Ib4d5503f05d2f2efe31a1be14e2fe6cac33730a9
Reviewed-on: https://go-review.googlesource.com/55143
Reviewed-by: Keith Randall <khr@golang.org>
The gofmt bug in question seems to be fixed (at least gofmt doesn't
complain), so reenable the commented-out ... test.
Change-Id: Icbfe0511160210557894ec8eb9b206aa6133d486
Reviewed-on: https://go-review.googlesource.com/55030
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
https://golang.org/cl/37508 added an escape analysis test for #12397 to
escape2.go but missed to add it to escape2n.go. The comment at the top
of the former states that the latter should contain all the same tests
and the tests only differ in using -N to compile. Conform to this by
adding the function issue12397 to escape2n.go as well.
Also fix a whitespace difference in escape2.go, so the two files match
exactly (except for the comment at the top).
Change-Id: I3a09cf95169bf2150a25d6b4ec9e147265d36760
Reviewed-on: https://go-review.googlesource.com/54610
Reviewed-by: Avelino <t@avelino.xxx>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
It is possible to have an unexported name with a nil package,
for an embedded field whose type is a pointer to an unexported type.
We must encode that fact in the type..namedata symbol name,
to avoid incorrectly merging an unexported name with an exported name.
Fixes#21120
Change-Id: I2e3879d77fa15c05ad92e0bf8e55f74082db5111
Reviewed-on: https://go-review.googlesource.com/50710
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Load/store-merging and move optimizations can result in unaligned
memory accesses. This is fine so long as the load/store instruction
used does not take a relative offset. In the SSA rules this means we
must not merge (MOVDaddr (SB)) ops into loads/stores unless we can
guarantee the alignment of the target.
Fixes#21048.
Change-Id: I70f13a62a148d5f0a56e704e8f76e36b4a4226d9
Reviewed-on: https://go-review.googlesource.com/49250
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Framepointer is the default now. Only print an X: list
if the settings are _not_ the default.
Before:
$ go tool compile -V
compile version devel +a5f30d9508 Sun Jul 16 14:43:48 2017 -0400 X:framepointer
$ go1.8 tool compile -V
compile version go1.8 X:framepointer
$
After:
$ go tool compile -V
compile version devel +a5f30d9508 Sun Jul 16 14:43:48 2017 -0400
$ go1.9 tool compile -V # imagined
compile version go1.9
$
Perpetuates #18317.
Change-Id: I981ba5c62be32e650a166fc9740703122595639b
Reviewed-on: https://go-review.googlesource.com/49252
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
On a slow or distracted machine, 0.1s is sometimes
not long enough for a non-blocking function call to complete.
This causes rare test flakes.
They can be easily reproduced by reducing the wait time to (say) 100ns.
For non-blocking functions, increase the window from 100ms to 10s.
Using different windows for block and non-blocking functions,
allows us to reduce the time for blocking functions.
The risk here is false negatives, but that risk is low;
this test is run repeatedly on many fast machines,
for which 10ms is ample time.
This reduces the time required to run the test by a factor of 10,
from ~1s to ~100ms.
Fixes#20299
Change-Id: Ice9a641a66c6c101d738a2ebe1bcb144ae3c9916
Reviewed-on: https://go-review.googlesource.com/47812
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
If the LHS is unassignable, there's no point in trying to make sure
the RHS can be assigned to it or making sure they're realizable
types. This is consistent with go/types.
In particular, this prevents "1 = 2" from causing a panic when "1"
still ends up with the type "untyped int", which is not realizable.
Fixes#20813.
Change-Id: I4710bdaac2e375ef12ec29b888b8ac84fb640e56
Reviewed-on: https://go-review.googlesource.com/46835
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Fixes crash when printing a related error message later on.
Fixes#20789.
Change-Id: I6d2c35aafcaeda26a211fc6c8b7dfe4a095a3efe
Reviewed-on: https://go-review.googlesource.com/46713
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Loops of the form "for i,e := range" needed to have their
condition rotated to the "bottom" for the preemptible loops
GOEXPERIMENT, but this caused a performance regression
because it degraded bounds check removal. For now, make
the loop rotation/guarding conditional on the experiment.
Fixes#20711.
Updates #10958.
Change-Id: Icfba14cb3b13a910c349df8f84838cf4d9d20cf6
Reviewed-on: https://go-review.googlesource.com/46410
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Minimal reconstruction of reported failure case.
Manually verified that test fails with CL 45911 reverted.
Change-Id: Ia5d11500d91b46ba1eb5d841db3987edb9136c39
Reviewed-on: https://go-review.googlesource.com/45970
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
Before CL 36170, we identified all function bodies that needed to be
exported before writing any export data.
With CL 36170, we started identifying additional functions while
exporting function bodies. As a consequence, we cannot use a
range-based for loop for iterating over function bodies anymore.
Fixes#18895.
Change-Id: I9cbefa8d311ca8c9898c8272b2ac365976b02396
Reviewed-on: https://go-review.googlesource.com/45817
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
These are used by DIV[U] and MOD[U] assembly instructions.
Add a test in the stdlib so we actually exercise linking
to these routines.
Update #19507
Change-Id: I0d8e19a53e3744abc0c661ea95486f94ec67585e
Reviewed-on: https://go-review.googlesource.com/45703
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The existing code used Type.String() to obtain the name of a type;
specifically type reflect.Method in this case. However, Type.String()
formatting is intended for error messages and uses the format
pkgpath.name instead of pkgname.name if a package (in this case
package reflect) is imported multiple times. As a result, the
reflect.Method type detection failed under peculiar circumstances
(see the included test case).
Thanks to https://github.com/ericlagergren for tracking down
an easy way to make the bug disappear (which in turn directly
led to the underlying cause).
Fixes#19028.
Change-Id: I1b9c5dfd183260a9be74969fe916a94146fc36da
Reviewed-on: https://go-review.googlesource.com/45777
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This results in names to unexported fields like
net.(*Dialer)."".deadline instead of net.(*Dialer).deadline.
Fixes#18419.
Change-Id: I0415c68b77cc16125c2401320f56308060ac3f25
Reviewed-on: https://go-review.googlesource.com/44070
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Arguments to inlined calls are hidden from setPos as follows:
args := as.Rlist
as.Rlist.Set(nil)
// setPos...
as.Rlist.Set(args.Slice())
Previously, this code had no effect since the value of as was
overwritten by the assignment in the retvars loop.
Fixes#19799.
Change-Id: Iaf97259f82fdba8b236136337cc42b2774c7fef5
Reviewed-on: https://go-review.googlesource.com/44351
Run-TryBot: David Lazar <lazard@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Apply the fix in CL 44355 to MIPS.
ARM64 has these rules but commented out for performance reason.
Fix the commented rules, in case they are enabled in the future.
Enhance the test so it triggers the failure on ARM and MIPS without
the fix.
Updates #20530.
Change-Id: I82d77448e3939a545fe519d0a29a164f8fa5417c
Reviewed-on: https://go-review.googlesource.com/44430
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Replacing byteload-of-bytestore-of-x with x is incorrect
when x contains a larger-than-byte value (and so on for
16 and 32-bit load/store pairs). Replace "x" with the
appropriate zero/sign extension of x, which if unnecessary
will be repaired by other rules.
Made logic for arm match x86 and amd64; yields minor extra
optimization, plus I am (much) more confident it's correct,
despite inability to reproduce bug on arm.
Ppc64 lacks this optimization, hence lacks this problem.
See related https://golang.org/cl/37154/Fixes#20530.
Change-Id: I6af9cac2ad43bee99cafdcb04725ce7e55a43323
Reviewed-on: https://go-review.googlesource.com/44355
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Instead of just printing the value, print the original node to make the
error more human-friendly. Also print the value if its string form is
different than the original node, to make sure it's obvious what value
was duplicated.
This means that "case '@', '@':", which used to print:
duplicate case 64 in switch
Will now print:
duplicate case '@' (value 64) in switch
Factor this logic out into its own function to reuse it in range cases
and any other place where we might want to print a node and its value in
the future.
Also needed to split the errorcheck files because expression switch case
duplicates are now detected earlier, so they stop the compiler before it
gets to generating the AST and detecting the type switch case
duplicates.
Fixes#20112.
Change-Id: I9009b50dec0d0e705e5de9c9ccb08f1dce8a5a99
Reviewed-on: https://go-review.googlesource.com/41852
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
These are functional tests, so it is safe to gofmt them.
Change-Id: I3067279c1d49809ac6a62054448ab8a6c3de9bda
Reviewed-on: https://go-review.googlesource.com/43623
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Cannot reproduce original problem. Compiler internals
have changed enough such that this appears to work now.
Restore original test (exported interfaces), but also
keep version of the test using non-exported interfaces.
Fixes#15596.
Change-Id: Idb32da80239963242bd5d1609343c80f19773b0c
Reviewed-on: https://go-review.googlesource.com/43622
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
When compiling concurrently, we walk all functions before compiling
any of them. Walking functions can cause variables to switch from
being non-addrtaken to addrtaken, e.g. to prepare for a runtime call.
Typechecking propagates addrtaken-ness of closure variables to
their outer variables, so that capturevars can decide whether to
pass the variable's value or a pointer to it.
When all functions are compiled immediately, as long as the containing
function is compiled prior to the closure, this propagation has no effect.
When compilation is deferred, though, in rare cases, this results in
a change in the addrtaken-ness of a variable in the outer function,
which in turn changes the compiler's output.
(This is rare because in a great many cases, a temporary has been
introduced, insulating the outer variable from modification.)
But concurrent compilation must generate identical results.
To fix this, track whether capturevars has run.
If it has, there is no need to update outer variables
when closure variables change.
Capturevars always runs before any functions are walked or compiled.
The remainder of the changes in this CL are to support the test.
In particular, -d=compilelater forces the compiler to walk all
functions before compiling any of them, despite being non-concurrent.
This is useful because -live is fundamentally incompatible with
concurrent compilation, but we want -c=1 to have no behavior changes.
Fixes#20250
Change-Id: I89bcb54268a41e8588af1ac8cc37fbef856a90c2
Reviewed-on: https://go-review.googlesource.com/42853
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Tuple ops are weird. They are essentially a pair of ops,
one which consumes a mem and one which generates a mem (the Select1).
The schedule pass didn't handle these quite right.
Fix the scheduler to include both parts of the paired op in
the store chain. That makes sure that loads are correctly ordered
with respect to the first of the pair.
Add a check for the ssacheck builder, that there is only one
live store at a time. I thought we already had such a check, but
apparently not...
Fixes#20335
Change-Id: I59eb3446a329100af38d22820b1ca2190ca46a78
Reviewed-on: https://go-review.googlesource.com/43294
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The writebarrier test has to change.
Now that T23 composite literals are passed to the backend,
they get SSA'd, so writes to their fields are treated separately,
so the relevant part of the first write to t23 is now a dead store.
Preserve the intent of the test by splitting it up into two functions.
Reduces code size a bit:
name old object-bytes new object-bytes delta
Template 386k ± 0% 386k ± 0% ~ (all equal)
Unicode 202k ± 0% 202k ± 0% ~ (all equal)
GoTypes 1.16M ± 0% 1.16M ± 0% ~ (all equal)
Compiler 3.92M ± 0% 3.91M ± 0% -0.19% (p=0.008 n=5+5)
SSA 7.91M ± 0% 7.91M ± 0% ~ (all equal)
Flate 228k ± 0% 228k ± 0% -0.05% (p=0.008 n=5+5)
GoParser 283k ± 0% 283k ± 0% ~ (all equal)
Reflect 952k ± 0% 952k ± 0% -0.06% (p=0.008 n=5+5)
Tar 188k ± 0% 188k ± 0% -0.09% (p=0.008 n=5+5)
XML 406k ± 0% 406k ± 0% -0.02% (p=0.008 n=5+5)
[Geo mean] 649k 648k -0.04%
Fixes#18872
Change-Id: Ifeed0f71f13849732999aa731cc2bf40c0f0e32a
Reviewed-on: https://go-review.googlesource.com/43154
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reuse block head or preceding instruction's line number for
register allocator's spill, fill, copy, rematerialization
instructionsl; and also for phi, and for no-src-pos
instructions. Assembler creates same line number tables
for copy-predecessor-line and for no-src-pos,
but copy-predecessor produces better-looking assembly
language output with -S and with GOSSAFUNC, and does not
require changes to tests of existing assembly language.
Split "copyInto" into two cases, one for register allocation,
one for otherwise. This caused the test score line change
count to increase by one, which may reflect legitimately
useful information preserved. Without any special treatment
for copyInto, the change count increases by 21 more, from
51 to 72 (i.e., quite a lot).
There is a test; using two naive "scores" for line number
churn, the old numbering is 2x or 4x worse.
Fixes#18902.
Change-Id: I0a0a69659d30ee4e5d10116a0dd2b8c5df8457b1
Reviewed-on: https://go-review.googlesource.com/36207
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
