Change-Id: Ice3aa807169f4fec85745a3991b1084a9f85c1b5
Reviewed-on: https://go-review.googlesource.com/20499
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Accessing the n'th field of a struct is fairly common, and in
particular accessing the 0'th field of the receiver parameter list is
very common. Add helper methods for both of these tasks and update
code to make use of them.
Change-Id: I81f551fecdca306b3800636caebcd0dc106f2ed7
Reviewed-on: https://go-review.googlesource.com/20498
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Dave Cheney <dave@cheney.net>
Also, more lazy variable declarations, and make Dijkstra happy by
replacing "goto loop" with a for loop.
Change-Id: Idf2cd779a92eb3f33bd3394e12c9a0be72002ff4
Reviewed-on: https://go-review.googlesource.com/20496
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Follow up to CL 20494 addressing Type.Copy and a few other tiny
cleanups.
Change-Id: I3d0913a9f50a22ac2fd802858b1a94c15c5cb1bc
Reviewed-on: https://go-review.googlesource.com/20501
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Better documentation. Change parameter types from **Type and int to
just *Type and bool. Make use of short var declarations.
Change-Id: I909846ba0df65cd2bc05ee145b72d60e881588bd
Reviewed-on: https://go-review.googlesource.com/20495
Reviewed-by: Dave Cheney <dave@cheney.net>
This should is preparatory cleanup to make it easier to use separate
types to represent each kind of Go type, rather than a single omnibus
Type struct with heavily overloaded fields.
Also, add TODO comments marking assignments that change an existing
Type's kind, as they need to be removed before we can factor Type.
Change-Id: If4b551fdea4ae045b10b1a3de2ee98f5cf32a517
Reviewed-on: https://go-review.googlesource.com/20494
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
With this, the start and end of geneq and genhash
are parallel. This removes a few rare nilchecks
from generated hash functions, but nothing
to write home about.
Change-Id: I3b4836111d04daa6f6834a579bbec374a3f42c70
Reviewed-on: https://go-review.googlesource.com/20456
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Mix in several other minor cleanups, including adding some new methods
to Nodes: Index, Addr, SetIndex, SetNodes.
Passes toolstash -cmp.
Update #14473.
Change-Id: I8bd4ae3fde7c5e20ba66e7dd1654fbc70c3ddeb8
Reviewed-on: https://go-review.googlesource.com/20491
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Today the linker keeps all methods of reachable types. This is
necessary if a program uses reflect.Value.Call. But while use of
reflection is widespread in Go for encoders and decoders, using
it to call a method is rare.
This CL looks for the use of reflect.Value.Call in a program, and
if it is absent, adopts a (reasonably conservative) method pruning
strategy as part of dead code elimination. Any method that is
directly called is kept, and any method that matches a used
interface's method signature is kept.
Whether or not a method body is kept is determined by the relocation
from its receiver's *rtype to its *rtype. A small change in the
compiler marks these relocations as R_METHOD so they can be easily
collected and manipulated by the linker.
As a bonus, this technique removes the text segment of methods that
have been inlined. Looking at the output of building cmd/objdump with
-ldflags=-v=2 shows that inlined methods like
runtime.(*traceAllocBlockPtr).ptr are removed from the program.
Relatively little work is necessary to do this. Linking two
examples, jujud and cmd/objdump show no more than +2% link time.
Binaries that do not use reflect.Call.Value drop 4 - 20% in size:
addr2line: -793KB (18%)
asm: -346KB (8%)
cgo: -490KB (10%)
compile: -564KB (4%)
dist: -736KB (17%)
fix: -404KB (12%)
link: -328KB (7%)
nm: -827KB (19%)
objdump: -712KB (16%)
pack: -327KB (14%)
yacc: -350KB (10%)
Binaries that do use reflect.Call.Value see a modest size decrease
of 2 - 6% thanks to pruning of unexported methods:
api: -151KB (3%)
cover: -222KB (4%)
doc: -106KB (2.5%)
pprof: -314KB (3%)
trace: -357KB (4%)
vet: -187KB (2.7%)
jujud: -4.4MB (5.8%)
cmd/go: -384KB (3.4%)
The trivial Hello example program goes from 2MB to 1.68MB:
package main
import "fmt"
func main() {
fmt.Println("Hello, 世界")
}
Method pruning also helps when building small binaries with
"-ldflags=-s -w". The above program goes from 1.43MB to 1.2MB.
Unfortunately the linker can only tell if reflect.Value.Call has been
statically linked, not if it is dynamically used. And while use is
rare, it is linked into a very common standard library package,
text/template. The result is programs like cmd/go, which don't use
reflect.Value.Call, see limited benefit from this CL. If binary size
is important enough it may be possible to address this in future work.
For #6853.
Change-Id: Iabe90e210e813b08c3f8fd605f841f0458973396
Reviewed-on: https://go-review.googlesource.com/20483
Reviewed-by: Russ Cox <rsc@golang.org>
Drops cmd/binary size from 14.41 MiB to 11.42 MiB.
Before:
text data bss dec hex filename
8121210 3521696 737960 12380866 bceac2 ../pkg/tool/linux_amd64/compile
bradfitz@dev-bradfitz-debian2:~/go/src$ ls -l ../pkg/tool/linux_amd64/compile
-rwxr-xr-x 1 bradfitz bradfitz 15111272 Mar 8 23:32 ../pkg/tool/linux_amd64/compile
a2afc0 51312 R html.statictmp_0085
6753f0 56592 T cmd/internal/obj/x86.doasm
625480 58080 T cmd/compile/internal/gc.typecheck1
f34c40 65688 D runtime.trace
be0a20 133552 D cmd/compile/internal/ppc64.varianttable
c013e0 265856 D cmd/compile/internal/arm.progtable
c42260 417280 D cmd/compile/internal/amd64.progtable
ca8060 417280 D cmd/compile/internal/x86.progtable
f44ce0 500640 D cmd/internal/obj/arm64.oprange
d0de60 534208 D cmd/compile/internal/ppc64.progtable
d90520 667520 D cmd/compile/internal/arm64.progtable
e334a0 790368 D cmd/compile/internal/mips64.progtable
a3e8c0 1579362 r runtime.pclntab
After:
text data bss dec hex filename
8128226 375954 246432 8750612 858614 ../pkg/tool/linux_amd64/compile
-rwxr-xr-x 1 bradfitz bradfitz 11971432 Mar 8 23:35 ../pkg/tool/linux_amd64/compile
6436d0 43936 T cmd/compile/internal/gc.walkexpr
c13ca0 45056 D cmd/compile/internal/ssa.opcodeTable
5d8ea0 50256 T cmd/compile/internal/gc.(*state).expr
818c50 50448 T cmd/compile/internal/ssa.rewriteValueAMD64_OpMove
a2d0e0 51312 R html.statictmp_0085
6753d0 56592 T cmd/internal/obj/x86.doasm
625460 58080 T cmd/compile/internal/gc.typecheck1
c38fe0 65688 D runtime.trace
a409e0 1578810 r runtime.pclntab
Fixes#14703
Change-Id: I2177596d5c7fd67db0a3c423cd90801cf52adb12
Reviewed-on: https://go-review.googlesource.com/20450
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
* Move lowering into a separate pass.
* SliceLen/SliceCap is now available to various intermediate passes
which use useful for bounds checking.
* Add a second opt pass to handle the new opportunities
Decreases the code size of binaries in pkg/tool/linux_amd64
by ~45K.
Updates #14564#14606
Change-Id: I5b2bd6202181c50623a3585fbf15c0d6db6d4685
Reviewed-on: https://go-review.googlesource.com/20172
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
It's only used once, so just make the caller responsible for iterating
both the receiver and input params.
Change-Id: Icb34f3f0cf96e80fbe27f3f49d12eddc26599b92
Reviewed-on: https://go-review.googlesource.com/20454
Reviewed-by: Dave Cheney <dave@cheney.net>
so the code is more readable.
Also use n[i] = val instead of n = append(n, val),
because this avoids a function call to append.
NOTE: compiles, but I had trouble running toolstash -cmp and need sleep
now.
@Ian this might save you some grunt work :-)
Change-Id: I2a4c70396c58905f7d5aabf83f3020f11dea0e89
Reviewed-on: https://go-review.googlesource.com/20430
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Suggested by Dave Cheney in golang.org/cl/20405.
Change-Id: I581c11ae80034cb6ebef3de976e8ae9484472322
Reviewed-on: https://go-review.googlesource.com/20453
Reviewed-by: Dave Cheney <dave@cheney.net>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This CL was automatically generated using a special-purpose AST
rewriting tool, followed by manual editing to put some comments back in
the right places and fix some bad line breaks.
The result is not perfect but it's a big step toward getting back to
sanity, and because it was automatically generated there is a decent
chance that it is correct.
Passes toolstash -cmp.
Update #14473.
Change-Id: I01c09078a6d78e2b008bc304d744b79469a38d3d
Reviewed-on: https://go-review.googlesource.com/20440
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
More idiomatic naming (in particular, matches the naming used for
go/types.Signature).
Also, convert more code to use these methods and/or IterFields.
(Still more to go; only made a quick pass for low hanging fruit.)
Passes toolstash -cmp.
Change-Id: I61831bfb1ec2cd50d4c7efc6062bca4e0dcf267b
Reviewed-on: https://go-review.googlesource.com/20451
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Alternative to golang.org/cl/19852. This memory layout doesn't have
an easy type representation, but it is noticeably smaller than the
current funcType, and saves significant extra space.
Some notes on the layout are in reflect/type.go:
// A *rtype for each in and out parameter is stored in an array that
// directly follows the funcType (and possibly its uncommonType). So
// a function type with one method, one input, and one output is:
//
// struct {
// funcType
// uncommonType
// [2]*rtype // [0] is in, [1] is out
// uncommonTypeSliceContents
// }
There are three arbitrary limits introduced by this CL:
1. No more than 65535 function input parameters.
2. No more than 32767 function output parameters.
3. reflect.FuncOf is limited to 128 parameters.
I don't think these are limits in practice, but are worth noting.
Reduces godoc binary size by 2.4%, 330KB.
For #6853.
Change-Id: I225c0a0516ebdbe92d41dfdf43f716da42dfe347
Reviewed-on: https://go-review.googlesource.com/19916
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Instead of a pointer on every rtype, use a bit flag to indicate that
the contents of uncommonType directly follows the rtype value when it
is needed.
This requires a bit of juggling in the compiler's rtype encoder. The
backing arrays for fields in the rtype are presently encoded directly
after the slice header. This packing requires separating the encoding
of the uncommonType slice headers from their backing arrays.
Reduces binary size of godoc by ~180KB (1.5%).
No measurable change in all.bash time.
For #6853.
Change-Id: I60205948ceb5c0abba76fdf619652da9c465a597
Reviewed-on: https://go-review.googlesource.com/19790
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Converting an and-K into a pair of shifts for K that will
fit in a one-byte argument is probably not an optimization,
and it also interferes with other patterns that we want to
see fire, like (<< (AND K)) [for small K] and bounds check
elimination for masked indices.
Turns out that on Intel, even 32-bit signed immediates beat
the shift pair; the size reduction of tool binaries is 0.09%
vs 0.07% for only the 8-bit immediates.
RLH found this one working on the new/next GC.
Change-Id: I2414a8de1dd58d680d18587577fbadb7ff4f67d9
Reviewed-on: https://go-review.googlesource.com/20410
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: David Chase <drchase@google.com>
Some cleaned up documentation, but no code changes.
Change-Id: I145398bb6d118c626ab3873ef75dbb64ebc286e9
Reviewed-on: https://go-review.googlesource.com/20404
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
* Simplify the nilcheck generated by
for _, e := range a {}
* No effect on the generated code because these nil checks
don't end up in the generated code.
* Useful for other analysis, e.g. it'll remove one dependecy
on the induction variable.
Change-Id: I6ee66ddfdc010ae22aea8dca48163303d93de7a9
Reviewed-on: https://go-review.googlesource.com/20307
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Make more idiomatic with a defer cleanup, which allows declaring
variables closer to their first use, rather than up front before the
first goto statement.
Also, split the legacy code generation code path into a separate
genlegacy function, analogous to the new genssa.
Passes toolstash -cmp.
Change-Id: I86c22838704f6861b75716ae64ba103b0e73b12f
Reviewed-on: https://go-review.googlesource.com/20353
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Accidentally added in https://golang.org/cl/20242.
This is in preparation for transformation by an automated tool.
Passes toolstash -cmp.
Update #14473.
Change-Id: I28c637d220df3ccaa8e368bfbea7282a6e66662e
Reviewed-on: https://go-review.googlesource.com/20402
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Bug accidentally inserted in https://golang.org/cl/20210. Doesn't seem
to make a difference, but restore original code anyhow.
Update #14473.
Change-Id: I9cf87987ff158e27c7231027819317cdde8c132c
Reviewed-on: https://go-review.googlesource.com/20401
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Deleting the string merging pass makes the linker 30-35% faster
but makes jujud (using the github.com/davecheney/benchjuju snapshot) 2.5% larger.
Two optimizations bring the space overhead down to 0.6%.
First, change the default alignment for string data to 1 byte.
(It was previously defaulting to larger amounts, usually pointer width.)
Second, write out the type string for T (usually a bigger expression) as "*T"[1:],
so that the type strings for T and *T share storage.
Combined, these obtain the bulk of the benefit of string merging
at essentially no cost. The remaining benefit from string merging
is not worth the excessive cost, so delete it.
As penance for making the jujud binary 0.6% larger,
the next CL in this sequence trims the reflect functype
information enough to make the jujud binary overall 0.75% smaller
(that is, that CL has a net -1.35% effect).
For #6853.
Fixes#14648.
Change-Id: I3fdd74c85410930c36bb66160ca4174ed540fc6e
Reviewed-on: https://go-review.googlesource.com/20334
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Without SSA:
$ go build -a -gcflags='-S -ssa=0' runtime 2>&1 | grep 'TEXT.*""\.init(SB)'
0x0000 00000 ($GOROOT/src/runtime/write_err.go:14) TEXT "".init(SB), $88-0
With SSA, before this CL:
$ go build -a -gcflags='-S -ssa=1' runtime 2>&1 | grep 'TEXT.*""\.init(SB)'
0x0000 00000 ($GOROOT/src/runtime/traceback.go:608) TEXT "".init(SB), $152-0
With SSA, after this CL:
$ go build -a -gcflags='-S -ssa=1' runtime 2>&1 | grep 'TEXT.*""\.init(SB)'
0x0000 00000 ($GOROOT/src/runtime/write_err.go:14) TEXT "".init(SB), $152-0
Change-Id: Ida3541e03a1af6ffc753ee5c3abeb653459edbf6
Reviewed-on: https://go-review.googlesource.com/20321
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This adds a heap-based proper priority queue to the
scheduler which made a relatively easy to test quite a few
heuristics that "ought to work well". For go tools
themselves (which may not be representative) the heuristic
that works best is (1) in line-number-order, then (2) from
more to fewer args, then (3) in variable ID order. Trying
to improve this with information about use at end of
blocks turned out to be fruitless -- all of my naive
attempts at using that information turned out worse than
ignoring it. I can confirm that the stores-early heuristic
tends to help; removing it makes the results slightly worse.
My metric is code size reduction, which I take to mean fewer
spills from register allocation. It's not uniform.
Here's the endpoints for "vet" from one set of pretty-good
heuristics (this is representative at least).
-2208 time.parse 13472 15680 -14.081633%
-1514 runtime.pclntab 1002058 1003572 -0.150861%
-352 time.Time.AppendFormat 9952 10304 -3.416149%
-112 runtime.runGCProg 1984 2096 -5.343511%
-64 regexp/syntax.(*parser).factor 7264 7328 -0.873362%
-44 go.string.alldata 238630 238674 -0.018435%
48 math/big.(*Float).round 1376 1328 3.614458%
48 text/tabwriter.(*Writer).writeLines 1232 1184 4.054054%
48 math/big.shr 832 784 6.122449%
88 go.func.* 75174 75086 0.117199%
96 time.Date 1968 1872 5.128205%
Overall there appears to be an 0.1% decrease in text size.
No timings yet, and given the distribution of size reductions
it might make sense to wait on those.
addr2line text (code) = -4392 bytes (-0.156273%)
api text (code) = -5502 bytes (-0.147644%)
asm text (code) = -5254 bytes (-0.187810%)
cgo text (code) = -4886 bytes (-0.148846%)
compile text (code) = -1577 bytes (-0.019346%) * changed
cover text (code) = -5236 bytes (-0.137992%)
dist text (code) = -5015 bytes (-0.167829%)
doc text (code) = -5180 bytes (-0.182121%)
fix text (code) = -5000 bytes (-0.215148%)
link text (code) = -5092 bytes (-0.152712%)
newlink text (code) = -5204 bytes (-0.196986%)
nm text (code) = -4398 bytes (-0.156018%)
objdump text (code) = -4582 bytes (-0.155046%)
pack text (code) = -4503 bytes (-0.294287%)
pprof text (code) = -6314 bytes (-0.085177%)
trace text (code) = -5856 bytes (-0.097818%)
vet text (code) = -5696 bytes (-0.117334%)
yacc text (code) = -4971 bytes (-0.213817%)
This leaves me sorely tempted to look into a "real" scheduler
to try to do a better job, but I think it might make more
sense to look into getting loop information into the
register allocator instead.
Fixes#14577.
Change-Id: I5238b83284ce76dea1eb94084a8cd47277db6827
Reviewed-on: https://go-review.googlesource.com/20240
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
When the pointer offset is non-zero in the small loads, we need to add the offset
when converting to the larger load.
Fixes#14694
Change-Id: I5ba8bcb3b9ce26c7fae0c4951500b9ef0fed54cd
Reviewed-on: https://go-review.googlesource.com/20333
Reviewed-by: Keith Randall <khr@golang.org>
Compile time is about the same. Getting rid of the nodeSeq interfaces,
particularly nodeSeqIterate, should produce some improvements.
Passes toolstash -cmp.
Update #14473.
Change-Id: I678abafdd9129c6cccb0ec980511932eaed496a0
Reviewed-on: https://go-review.googlesource.com/20343
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
It is only necessary in a few places, and this inlining will
simplify the transition away from NodeLists.
Passes toolstash -cmp.
Change-Id: I4ee9b4bf56ffa04df23e20a0a83b302d36b33510
Reviewed-on: https://go-review.googlesource.com/20290
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Opt for replacements that avoid any assumptions
about the representations in use.
Passes toolstash -cmp.
Change-Id: Ia858a33abcae344e03fc1862fc9b0e192fde80c1
Reviewed-on: https://go-review.googlesource.com/20279
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Fix some test output while we're here.
Change-Id: I265cedc222e078eff120f268b92451e12b0400b2
Reviewed-on: https://go-review.googlesource.com/20294
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Move initproginfo and initvariants to ppc64.Main to avoid checking that
the tables are initialised every time.
Change-Id: I95ff4146a7abc18c42a20bfad716cc80ea8367e5
Reviewed-on: https://go-review.googlesource.com/20286
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Found by temporarily flipping fields from *NodeList to Nodes and fixing
all the compilation errors. This CL does not actually change any
fields.
Passes toolstash -cmp.
Update #14473.
Change-Id: Ib98fa37e8752f96358224c973a743618a6a0e736
Reviewed-on: https://go-review.googlesource.com/20320
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Eliminates type conversions in a bunch of Oconv(int(n.Op), ...) calls.
Notably, this identified a misuse of Oconv in amd64/gsubr.go to try to
print an assembly instruction op instead of a compiler node op.
Change-Id: I93b5aa49fe14a5eaf868b05426d3b8cd8ab52bc5
Reviewed-on: https://go-review.googlesource.com/20298
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
In increment and decrement statements, explicit check that the type
of operand is numeric earlier. This avoids a related but less clear
error about converting "1" to be emitted.
So, when compiling
package main
func main() {
var x bool
x++
}
instead of emitting two errors
prog.go:5: cannot convert 1 to type bool
prog.go:5: invalid operation: x++ (non-numeric type bool)
just emits the second error.
Fixes#12525.
Change-Id: I6e81330703765bef0d6eb6c57098c1336af7c799
Reviewed-on: https://go-review.googlesource.com/20245
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
