*64 is <<6, not <<5.

Change-Id: I2eb7e113d5003b2c77fbd3abc3defc4d98976a5e
Reviewed-on: https://go-review.googlesource.com/12323Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Keep track of the outargs size needed at each call.
Compute the size of the outargs section of the stack frame.  It's just
the max of the outargs size at all the callsites in the function.

Change-Id: I3d0640f654f01307633b1a5f75bab16e211ea6c0
Reviewed-on: https://go-review.googlesource.com/12178Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

Change-Id: Ia56ee9798eefe123d4da04138a6a559d2c25ddf3
Reviewed-on: https://go-review.googlesource.com/12312Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

If we've already hit an Unimplemented, there may be important
SSA invariants that do not hold and which could cause
ssa.Compile to hang or spin.

While we're here, make detected dependency cycles stop execution.

Change-Id: Ic7d4eea659e1fe3f2c9b3e8a4eee5567494f46ad
Reviewed-on: https://go-review.googlesource.com/12310Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Implement ODOT.  Similar to ArrayIndex, StructSelect selects a field
out of a larger Value.

We may need more ways to rewrite StructSelect, but StructSelect/Load
is the typical way it is used.

Change-Id: Ida7b8aab3298f4754eaf9fee733974cf8736e45d
Reviewed-on: https://go-review.googlesource.com/12265Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Implements the simple Lengauer-Tarjan algorithm for dominator
and post-dominator calculation.

benchmark                           old ns/op     new ns/op     delta
BenchmarkDominatorsLinear-8         1403862       1292741       -7.92%
BenchmarkDominatorsFwdBack-8        1270633       1428285       +12.41%
BenchmarkDominatorsManyPred-8       225932354     1530886       -99.32%
BenchmarkDominatorsMaxPred-8        445994225     1393612       -99.69%
BenchmarkDominatorsMaxPredVal-8     447235248     1246899       -99.72%
BenchmarkNilCheckDeep1-8            829           1259          +51.87%
BenchmarkNilCheckDeep10-8           2199          2397          +9.00%
BenchmarkNilCheckDeep100-8          57325         29405         -48.70%
BenchmarkNilCheckDeep1000-8         6625837       2933151       -55.73%
BenchmarkNilCheckDeep10000-8        763559787     319105541     -58.21%

benchmark                           old MB/s     new MB/s     speedup
BenchmarkDominatorsLinear-8         7.12         7.74         1.09x
BenchmarkDominatorsFwdBack-8        7.87         7.00         0.89x
BenchmarkDominatorsManyPred-8       0.04         6.53         163.25x
BenchmarkDominatorsMaxPred-8        0.02         7.18         359.00x
BenchmarkDominatorsMaxPredVal-8     0.02         8.02         401.00x
BenchmarkNilCheckDeep1-8            1.21         0.79         0.65x
BenchmarkNilCheckDeep10-8           4.55         4.17         0.92x
BenchmarkNilCheckDeep100-8          1.74         3.40         1.95x
BenchmarkNilCheckDeep1000-8         0.15         0.34         2.27x
BenchmarkNilCheckDeep10000-8        0.01         0.03         3.00x

Change-Id: Icec3d774422a9bc64914779804c8c0ab73aa72bf
Reviewed-on: https://go-review.googlesource.com/11971Reviewed-by: Keith Randall <khr@golang.org>

Change-Id: I15aee8095e6388822e2222f1995fe2278ac956ca
Reviewed-on: https://go-review.googlesource.com/12129Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

Phi ops should always be scheduled first.  They have the semantics
of all happening simultaneously at the start of the block.  The regalloc
phase assumes all the phis will appear first.

Change-Id: I30291e1fa384a0819205218f1d1ec3aef6d538dd
Reviewed-on: https://go-review.googlesource.com/12154Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

Change-Id: I02b8fb277b486eaf0916ddcd8f28c062d4022d4b
Reviewed-on: https://go-review.googlesource.com/12150Reviewed-by: Keith Randall <khr@golang.org>

Change-Id: If8a9d5901fa2141d16b1c8d001761ea62bc23207
Reviewed-on: https://go-review.googlesource.com/12141Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I3f3ac3055c93858894b8852603d79592bbc1696b
Reviewed-on: https://go-review.googlesource.com/12140Reviewed-by: Keith Randall <khr@golang.org>

Change-Id: I4c9bcea01e2c4333c2a3592b66f1da9f424747a4
Reviewed-on: https://go-review.googlesource.com/12130Reviewed-by: Keith Randall <khr@golang.org>

Change-Id: Ibd6a59db2d5feea41a21fbea5c1a7fdd49238aa8
Reviewed-on: https://go-review.googlesource.com/12131Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

Joint hacking with josharian. Hints from matloob and Todd Neal.

Now with tests, and OROR.

Change-Id: Iff8826fde475691fb72a3eea7396a640b6274af9
Reviewed-on: https://go-review.googlesource.com/12041Reviewed-by: Keith Randall <khr@golang.org>

An empty label statement can just be ignored, as it cannot
be the target of any gotos.

Tests are already in test/fixedbugs/issue7538*.go

Fixes #11589
Fixes #11593

Change-Id: Iadcd639e7200ce16aa40fd7fa3eaf82522513e82
Reviewed-on: https://go-review.googlesource.com/12093Reviewed-by: Daniel Morsing <daniel.morsing@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I26c268f46dcffe39912b8c92ce9abb875310934f
Reviewed-on: https://go-review.googlesource.com/12100Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I3e2e8862f2fde4349923016b97e8330b0d494e0e
Reviewed-on: https://go-review.googlesource.com/12092Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

Co-hacking with josharian at Gophercon.

Change-Id: Ia59dfab676c6ed598c2c25483439cd1395a4ea87
Reviewed-on: https://go-review.googlesource.com/12029Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

And dependent fixes and misc cleanup.

Co-hacking with josharian at Gophercon.

Change-Id: Ib85dc13b303929017eb0a4d2fc2f603485f7479b
Reviewed-on: https://go-review.googlesource.com/12027Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #11676

Change-Id: I941f951633c89bb1454ce6d1d1b4124d46a7d9dd
Reviewed-on: https://go-review.googlesource.com/12091Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Since the spec guarantees than 0 <= len always:

https://golang.org/ref/spec#Length_and_capacity

replace len(...) <= 0 check with len(...) == 0 check

Change-Id: I5517a9cb6b190f0b1ee314a67487477435f3b409
Reviewed-on: https://go-review.googlesource.com/12034Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

If an expression has an Ninit list, generate code for it.
Required for (at least) OANDAND.

Change-Id: I94c9e22e2a76955736f4a8e574d92711419c5e5c
Reviewed-on: https://go-review.googlesource.com/12072Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

removePredecessor can change which blocks are live.
However, it cannot remove dead blocks from the function's
slice of blocks because removePredecessor may have been
called from within a function doing a walk of the blocks.

CL 11879 did not handle this correctly and broke the build.

To fix this, mark the block as dead but leave its actual
removal for a deadcode pass. Blocks that are dead must have
no successors, predecessors, values, or control values,
so they will generally be ignored by other passes.
To be safe, we add a deadcode pass after the opt pass,
which is the only other pass that calls removePredecessor.

Two alternatives that I considered and discarded:

(1) Make all call sites aware of the fact that removePrecessor
might make arbitrary changes to the list of blocks. This
will needlessly complicate callers.

(2) Handle the things that can go wrong in practice when
we encounter a dead-but-not-removed block. CL 11930 takes
this approach (and the tests are stolen from that CL).
However, this is just patching over the problem.

Change-Id: Icf0687b0a8148ce5e96b2988b668804411b05bd8
Reviewed-on: https://go-review.googlesource.com/12004Reviewed-by: Todd Neal <todd@tneal.org>
Reviewed-by: Michael Matloob <michaelmatloob@gmail.com>

Reduces 'go run run.go 64bit.go' from 23s to 8s on my machine.

Change-Id: Ie5b642d0abb56e8eb3899d69472bc88a85a1c985
Reviewed-on: https://go-review.googlesource.com/12023Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This is a prerequisite for implementing break and continue;
blocks ending in break or continue need to have
the increment block as a successor.

While we're here, implement for loops with no condition.

Change-Id: I85d8ba020628d805bfd0bd583dfd16e1be6f6fae
Reviewed-on: https://go-review.googlesource.com/11941Reviewed-by: Keith Randall <khr@golang.org>

This change has some tests verifying functionality and an assortment of
benchmarks of various block lists. It modifies NewBlock to allocate in
contiguous blocks improving the performance of intersect() for extremely
large graphs by 30-40%.

benchmark                           old ns/op      new ns/op     delta
BenchmarkDominatorsLinear-8         1185619        901154        -23.99%
BenchmarkDominatorsFwdBack-8        1302138        863537        -33.68%
BenchmarkDominatorsManyPred-8       404670521      247450911     -38.85%
BenchmarkDominatorsMaxPred-8        455809002      471675119     +3.48%
BenchmarkDominatorsMaxPredVal-8     819315864      468257300     -42.85%

BenchmarkNilCheckDeep1-8            766            706           -7.83%
BenchmarkNilCheckDeep10-8           2553           2209          -13.47%
BenchmarkNilCheckDeep100-8          58606          57545         -1.81%
BenchmarkNilCheckDeep1000-8         7753012        8025750       +3.52%
BenchmarkNilCheckDeep10000-8        1224165946     789995184     -35.47%

Change-Id: Id3d6bc9cb1138e8177934441073ac7873ddf7ade
Reviewed-on: https://go-review.googlesource.com/11716Reviewed-by: Keith Randall <khr@golang.org>

The removal of if false { ... } blocks in the opt
pass exposed that removePredecessor needed
to do more cleaning, on pain of failing later
consistency checks.

Change-Id: I45d4ff7e1f7f1486fdd99f867867ce6ea006a288
Reviewed-on: https://go-review.googlesource.com/11879Reviewed-by: Keith Randall <khr@golang.org>

Change-Id: Ie23b13142fd820d7071a348a8370175e58b76d64
Reviewed-on: https://go-review.googlesource.com/11878Reviewed-by: Keith Randall <khr@golang.org>

Loops such as

func f(c chan int) int {
	for x := range c {
		return x
	}
	return 0
}

don't loop. Remove the assumption that they must.

Partly fixes the build.

Change-Id: I766cebeec8e36d14512bea26f54c06c8eaf95e23
Reviewed-on: https://go-review.googlesource.com/11876Reviewed-by: Keith Randall <khr@golang.org>

There is clearly work to do to fix labels and gotos.
The compiler currently hangs on ken/label.go.

For the moment, stop the bleeding.

Fixes the build.

Change-Id: Ib68360d583cf53e1a8ca4acff50644b570382728
Reviewed-on: https://go-review.googlesource.com/11877Reviewed-by: Keith Randall <khr@golang.org>

Partly fixes the build, by punting.
Other things have broken in the meantime.

Change-Id: I1e2b8310057cbbbd9ffc501ef51e744690e00726
Reviewed-on: https://go-review.googlesource.com/11875Reviewed-by: Keith Randall <khr@golang.org>

Change-Id: I4e4200b0fa847a1ff8a8b7d1e318bbc1c5e26b5b
Reviewed-on: https://go-review.googlesource.com/11874Reviewed-by: Keith Randall <khr@golang.org>

Doesn't fix the build entirely, but does make it get to the race
detector tests.

Change-Id: Ie986d52374936855b7ee975dc68742306527eb15
Reviewed-on: https://go-review.googlesource.com/11835Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>

These additional checks were useful in
tracking down the broken build (CL 11238).

This CL does not fix the build, sadly.

Change-Id: I34de3bed223f450aaa97c1cadaba2e4e5850050b
Reviewed-on: https://go-review.googlesource.com/11681Reviewed-by: Keith Randall <khr@golang.org>

This will make it possible for us to start implementing interfaces
and other stack allocated types which are more than one machine word.

Change-Id: I52b187a791cf1919cb70ed6dabdc9f57b317ea83
Reviewed-on: https://go-review.googlesource.com/11631Reviewed-by: Keith Randall <khr@golang.org>

Forgot to add this in the tip merge.

Change-Id: I0e5a2681133f4ae7a7c360ae2c2d71d46420c693
Reviewed-on: https://go-review.googlesource.com/11793Reviewed-by: Keith Randall <khr@golang.org>

Semi-regular merge from tip into ssa branch.

Change-Id: I9cbe23f566410496d4ceb97c1435e2df7f2b56ec

Everything in the library but crypto and net.

Change-Id: I89b21b9621e6d338fa1891da0eabba5d7d2fe349
Reviewed-on: https://go-review.googlesource.com/11820Reviewed-by: Russ Cox <rsc@golang.org>

Adding a mutex was easier than documenting it, and is consistent with
gob.

Fixes #9847

Change-Id: Ifa94c17e7c11643add81b35431ef840b794d78b1
Reviewed-on: https://go-review.googlesource.com/11682Reviewed-by: Andrew Gerrand <adg@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

See RFC 7230.

Thanks to Régis Leroy for the report.

Change-Id: Ic1779bc2180900430d4d7a4938cac04ed73c304c
Reviewed-on: https://go-review.googlesource.com/11810Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>