To reduce the number of spills, give any non-phi values whose argument
is the control the same priority as the control.
With mask.bash, this reduces regenerated flags from 603 to 240.
Change-Id: I26883d69e80357c56b343428fb528102b3f26e7a
Reviewed-on: https://go-review.googlesource.com/14042
Reviewed-by: Keith Randall <khr@golang.org>
Update #10994
CASE and BCASE were used by 5c in switch statements, cmd/compile
does not use them.
Change-Id: I7a578c461b52b94690e35460926849b28971b770
Reviewed-on: https://go-review.googlesource.com/14009
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This helps vet see a real issue:
cmd/internal/gc$ go vet
gen.go:1223: unreachable code
Fixes#12106.
Change-Id: I720868b07ae6b6d5a4dc6b238baa8c9c889da6d8
Reviewed-on: https://go-review.googlesource.com/14083
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Instead of trying to delete dead code as soon as we find it, just
mark it as dead using a PlainAndDead block kind. The deadcode pass
will do the real removal.
This way is somewhat more efficient because we don't need to mess
with successor and predecessor lists of all the dead blocks.
Fixes#12347
Change-Id: Ia42d6b5f9cdb3215a51737b3eb117c00bd439b13
Reviewed-on: https://go-review.googlesource.com/14033
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
This also fixes the encoding/gob TestTopLevelNilPointer failure.
Change-Id: I9b29a6fddffd51af305c685f3a8e2a0594bfeeab
Reviewed-on: https://go-review.googlesource.com/14032
Reviewed-by: Keith Randall <khr@golang.org>
addEdge had two identical implementations so make it an exported method
on Block.
Change-Id: I8c21655a9dc5074fefd7f63b2f5b51897571e608
Reviewed-on: https://go-review.googlesource.com/14040
Reviewed-by: Keith Randall <khr@golang.org>
Frontend has already rewriten fallthrough statements, we just need to
ignore them.
Change-Id: Iadf89b06a9f8f9e6e2e1e87c934f31add77a19a1
Reviewed-on: https://go-review.googlesource.com/14029
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Val.Ctype used to be struct field, it's now a method.
Change-Id: I08f0b32b66dba15b2a392e84a557efb905b530cb
Reviewed-on: https://go-review.googlesource.com/14031
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Fixes build. There may be no current block.
Change-Id: I0da8bab133dc207124556927698e7cd682e64ef5
Reviewed-on: https://go-review.googlesource.com/13989
Reviewed-by: Keith Randall <khr@golang.org>
Add a check to make sure value arguments dominate the value.
Phi elim output used to fail this test. When eliminating
redundant phis, phi elim was using one of the args and not
the ultimate source. For example:
b1: x = ...
-> b2 b3
b2: y = Copy x b3: z = Copy x
-> b4 -> b4
b4: w = phi y z
Phi elim eliminates w, but it used to replace w with (Copy y).
That's bad as b2 does not dominate b4. Instead we should
replace w with (Copy x).
Fixes#12347
Change-Id: I9f340cdabcda8e2e90359fb4f9250877b1fffe98
Reviewed-on: https://go-review.googlesource.com/13986
Reviewed-by: David Chase <drchase@google.com>
Still to do: arithmetic
Change-Id: I31fd23b34980c9ed4b4e304b8597134b2ba6ca5c
Reviewed-on: https://go-review.googlesource.com/14024
Reviewed-by: Keith Randall <khr@golang.org>
The old backend doesn't like ideal types,
and we want to reuse its stackmap generation.
OOROR and OANDAND expressions have ideal type.
The old backend didn't care,
because those expressions got rewritten away into
jumps before stackmap generation.
Fix the type during conversion.
Change-Id: I488e7499298d9aec71da39c202f6a7235935bc8d
Reviewed-on: https://go-review.googlesource.com/13980
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The code previously always used AX causing errors. For now, just
switch off the type in order to at least generate valid code.
Change-Id: Iaf13120a24b62456b9b33c04ab31f2d5104b381b
Reviewed-on: https://go-review.googlesource.com/13943
Reviewed-by: David Chase <drchase@google.com>
No longer used after previous hashmap change.
Change-Id: I558470f872281e84a78406132df4e391d077b833
Reviewed-on: https://go-review.googlesource.com/13785
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Previously t.zero always pointed to runtime.zerovalue. Change the hashmap code
to always return a runtime pointer directly, and change that pointer to point
to a larger buffer if one is needed.
(It might be better to only copy from the pointer returned by the mapaccess
functions when the value type is small enough and have the compiler insert
explicit zeroing for larger value types, but I tried and failed to do this).
This removes all uses of the zero field of the type data; the field itself can
be removed in a separate change.
Fixes#11491
Change-Id: I5b81752ff4067d74a5a281c41e88f151bae0171e
Reviewed-on: https://go-review.googlesource.com/13784
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Add blocks to remove critical edges, even when it looks like
there's no phi that requires it. Regalloc still likes to have
critical-edge-free graphs for other reasons.
Change-Id: I69f8eaecbc5d79ab9f2a257c2e289d60b18e43c8
Reviewed-on: https://go-review.googlesource.com/13933
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
The issue 12226 has been caused by the allocation of the same register
for the equality check of two byte values. The code in cgen.go freed the
register for the second operand before the allocation of the register
for the first operand.
Fixes#12226
Change-Id: Ie4dc33a488bd48a17f8ae9b497fd63c1ae390555
Reviewed-on: https://go-review.googlesource.com/13771
Reviewed-by: Russ Cox <rsc@golang.org>
Add a new function and generic operation to handle
bounds checking for slices. Unlike the index
bounds checking the index can be equal to the upper
bound.
Do gc-friendly slicing that generates proper code for
0-length result slices.
This is a takeover of Alexandru's original change,
(https://go-review.googlesource.com/#/c/12764/)
submittable now that the decompose phase is in.
Change-Id: I17d164cf42ed7839f84ca949c6ad3289269c9160
Reviewed-on: https://go-review.googlesource.com/13903
Reviewed-by: David Chase <drchase@google.com>
Basic ops, no particular optimization in the pattern
matching yet (e.g. x!=x for Nan detection, x cmp constant,
etc.)
Change-Id: I0043564081d6dc0eede876c4a9eb3c33cbd1521c
Reviewed-on: https://go-review.googlesource.com/13704
Reviewed-by: Keith Randall <khr@golang.org>
A comparison of the form l == r where l is an interface and r is
concrete performs a type assertion on l to convert it to r's type.
However, the compiler fails to zero the temporary where the result of
the type assertion is written, so if the type is a pointer type and a
stack scan occurs while in the type assertion, it may see an invalid
pointer on the stack.
Fix this by zeroing the temporary. This is equivalent to the fix for
type switches from c4092ac.
Fixes#12253.
Change-Id: Iaf205d456b856c056b317b4e888ce892f0c555b9
Reviewed-on: https://go-review.googlesource.com/13872
Reviewed-by: Russ Cox <rsc@golang.org>
MOVXload and MOVXstore opcodes have both an auxint offset
and an aux offset (a symbol name, like a local or arg or global).
Make sure we keep those values during rewrites.
Change-Id: Ic9fd61bf295b5d1457784c281079a4fb38f7ad3b
Reviewed-on: https://go-review.googlesource.com/13849
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
This CL takes a simple approach to spilling and loading flags.
We never spill. When a load is needed, we recalculate,
loading the arguments as needed.
This is simple and architecture-independent.
It is not very efficient, but as of this CL,
there are fewer than 200 flag spills during make.bash.
This was tested by manually reverting CLs 13813 and 13843,
causing SETcc, MOV, and LEA instructions to clobber flags,
which dramatically increases the number of flags spills.
With that done, all stdlib tests that used to pass
still pass.
For future reference, here are some other, more efficient
amd64-only schemes that we could adapt in the future if needed.
(1) Spill exactly the flags needed.
For example, if we know that the flags will be needed
by a SETcc or Jcc op later, we could use SETcc to
extract just the relevant flag. When needed,
we could use TESTB and change the op to JNE/SETNE.
(Alternatively, we could leave the op unaltered
and prepare an appropriate CMPB instruction
to produce the desired flag.)
However, this requires separate handling for every
instruction that uses the flags register,
including (say) SBBQcarrymask.
We could enable this on an ad hoc basis for common cases
and fall back to recalculation for other cases.
(2) Spill all flags with PUSHF and POPF
This modifies SP, which the runtime won't like.
It also requires coordination with stackalloc to
make sure that we have a stack slot ready for use.
(3) Spill almost all flags with LAHF, SETO, and SAHF
See http://blog.freearrow.com/archives/396
for details. This would handle all the flags we currently
use. However, LAHF and SAHF are not universally available
and it requires arranging for AX to be free.
Change-Id: Ie36600fd8e807ef2bee83e2e2ae3685112a7f276
Reviewed-on: https://go-review.googlesource.com/13844
Reviewed-by: Keith Randall <khr@golang.org>
This further reduces the number of flags spills
during make.bash by about 50%.
Note that GetG is implemented by one or two MOVs,
which is why it does not clobber flags.
Change-Id: I6fede8c027b7dc340e00d1e15df1b87bf2b2d9ec
Reviewed-on: https://go-review.googlesource.com/13843
Reviewed-by: Keith Randall <khr@golang.org>
Mark these as unimplemented so we don't generate bad code.
Change-Id: I101190c40a753faaa82193ac37e2978b20a96e4e
Reviewed-on: https://go-review.googlesource.com/13748
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Currently an expression like
var v = 0 >> 1000
is rejected by gc with a "stupid shift" error, while gotype
compiles it successfully.
As suggested by gri on the issue tracker, allow an rsh right
operand to be any valid uint value.
Fixes#11328
Change-Id: I6ccb3b7f842338d91fd26ae37dd4fa279d7fc440
Reviewed-on: https://go-review.googlesource.com/13777
Reviewed-by: Robert Griesemer <gri@golang.org>
This updates the big package used by the compiler to match the
public big package which contains some updates and bug fixes.
Obtained by running vendor.bash in the internal/big directory.
No manual changes.
Change-Id: I299aecc6599d4a745a721ce48def32449640dbb2
Reviewed-on: https://go-review.googlesource.com/13815
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This CL makes function printing and HTML generation
accurate after regalloc.
Prior to this CL, text and HTML function outputs
showed live values and blocks as dead.
Change-Id: I70669cd8641af841447fc5d2ecbd754b281356f0
Reviewed-on: https://go-review.googlesource.com/13812
Reviewed-by: Keith Randall <khr@golang.org>
This reduces the number of flags spilled during
make.bash by > 90%.
I am working (slowly) on the rest.
Change-Id: I3c08ae228c33e2f726f615962996f0350c8d592b
Reviewed-on: https://go-review.googlesource.com/13813
Reviewed-by: David Chase <drchase@google.com>
Decompose breaks compound objects up into pieces that can be
operated on by the target architecture. The decompose pass only
does phi ops, the rest is done by the rewrite rules in generic.rules.
Compound objects include strings,slices,interfaces,structs,arrays.
Arrays aren't decomposed because of indexing (we could support
constant indexes, but dynamic indexes can't be handled using SSA).
Structs will come in a subsequent CL.
TODO: after this pass we have lost the association between, e.g.,
a string's pointer and its size. It would be nice if we could keep
that information around for debugging info somehow.
Change-Id: I6379ab962a7beef62297d0f68c421f22aa0a0901
Reviewed-on: https://go-review.googlesource.com/13683
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Implement index check panics (and slice check panics, for when
we need those).
Clean up nil check. Now that the new regalloc is in we can use
the register we just tested as the address 0 destination.
Remove jumps after panic calls, they are unreachable.
Change-Id: Ifee6e510cdea49cc7c7056887e4f06c67488d491
Reviewed-on: https://go-review.googlesource.com/13687
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
for i, v := range a {
}
Walk converts this to a regular for loop, like this:
for i := 0, p := &a[0]; i < len(a); i++, p++ {
v := *p
}
Unfortunately, &a[0] fails its bounds check when a is
the empty slice (or string). The old compiler gets around this
by marking &a[0] as Bounded, meaning "don't emit bounds checks
for this index op". This change makes SSA honor that same mark.
The SSA compiler hasn't implemented bounds check panics yet,
so the failed bounds check just causes the current routine
to return immediately.
Fixes bytes package tests.
Change-Id: Ibe838853ef4046c92f76adbded8cca3b1e449e0b
Reviewed-on: https://go-review.googlesource.com/13685
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Adds support for high multiply which is used by the frontend when
rewriting const division. The frontend currently only does this for 8,
16, and 32 bit integer arithmetic.
Change-Id: I9b6c6018f3be827a50ee6c185454ebc79b3094c8
Reviewed-on: https://go-review.googlesource.com/13696
Reviewed-by: Keith Randall <khr@golang.org>
Store ops now need their size in the auxint field. I missed this one.
Change-Id: I050fd6b5b00579883731702c426edafa3a5f7561
Reviewed-on: https://go-review.googlesource.com/13682
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Tested by hand.
Only lines of code changing are protected by Fieldtrack_enabled > 0,
which is never true in standard Go distributions.
Fixes#12171.
Change-Id: I963b9997dac10829db8ad4bfc97a7d6bf14b55c6
Reviewed-on: https://go-review.googlesource.com/13676
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Implement a global (whole function) register allocator.
This replaces the local (per basic block) register allocator.
Clobbering of registers by instructions is handled properly.
A separate change will add the correct clobbers to all the instructions.
Change-Id: I38ce4dc7dccb8303c1c0e0295fe70247b0a3f2ea
Reviewed-on: https://go-review.googlesource.com/13622
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Todd Neal <todd@tneal.org>
This was missing from CL 13472
due to a badly synced client.
Change-Id: If59fc669125dd1caa335dacfbf0f8dbd7b074312
Reviewed-on: https://go-review.googlesource.com/13639
Reviewed-by: Keith Randall <khr@golang.org>
Added F32 and F64 load, store, and addition.
Added F32 and F64 multiply.
Added F32 and F64 subtraction and division.
Added X15 to "clobber" for FP sub/div
Added FP constants
Added separate FP test in gc/testdata
Change-Id: Ifa60dbad948a40011b478d9605862c4b0cc9134c
Reviewed-on: https://go-review.googlesource.com/13612
Reviewed-by: Keith Randall <khr@golang.org>
Fixesgolang/go#12133
CL 13630 fixed the use of a stale reg[] array in the various arch
backends which was causing the check in clearfat to pass
unconditionally on arm64.
With this check fixed, arm64 now considers REGRT1 to always be in use
as it is part of the reserved register set, see arm64/gsubr.go.
However, ppc64 does not consider REGRT1 and REGRT2 to be part of its
reserved set, so its identical clearfat check passes.
This CL removes the Reginuse check inside clearfat as REGRT1 is
guarenteed always be free on arm64.
Change-Id: I4719150d3c3378fae155b863c474529df18d4c17
Reviewed-on: https://go-review.googlesource.com/13650
Reviewed-by: Russ Cox <rsc@golang.org>
Using the type of the store argument is not safe, it may change
during rewriting, giving us the wrong store width.
(Store ptr (Trunc32to16 val) mem)
This should be a 2-byte store. But we have the rule:
(Trunc32to16 x) -> x
So if the Trunc rewrite happens before the Store -> MOVW rewrite,
then the Store thinks that the value it is storing is 4 bytes
in size and uses a MOVL. Bad things ensue.
Fix this by encoding the store width explicitly in the auxint field.
In general, we can't rely on the type of arguments, as they may
change during rewrites. The type of the op itself (as used by
the Load rules) is still ok to use.
Change-Id: I9e2359e4f657bb0ea0e40038969628bf0f84e584
Reviewed-on: https://go-review.googlesource.com/13636
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
The reg[] array in .../gc is where truth lies. The copy in .../ARCH
is incorrect as it is mostly not updated to reflect regalloc decisions.
This bug was introduced in the rewrite
https://go-review.googlesource.com/#/c/7853/. The new reg[] array was
introduced in .../gc but not all of the uses were removed in the
.../ARCH directories.
Fixes#12133
Change-Id: I6364fc403cdab92d802d17f2913ba1607734037c
Reviewed-on: https://go-review.googlesource.com/13630
Reviewed-by: Russ Cox <rsc@golang.org>
Mul8 is lowered to MULW, but the rules for constant
folding do not handle the fact that the operands
are int8.
Change-Id: I2c336686d86249393a8079a471c6ff74e6228f3d
Reviewed-on: https://go-review.googlesource.com/13642
Reviewed-by: Keith Randall <khr@golang.org>
Disable CX as output for shift operations.
Change-Id: I85e6b22d09009b38847082dc375b6108c2dee80a
Reviewed-on: https://go-review.googlesource.com/13370
Reviewed-by: Keith Randall <khr@golang.org>
This is an initial implementation.
There are many rough edges and TODOs,
which will hopefully be polished out
with use.
Fixes#12071.
Change-Id: I1d6fd5a343063b5200623bceef2c2cfcc885794e
Reviewed-on: https://go-review.googlesource.com/13472
Reviewed-by: Keith Randall <khr@golang.org>
This omission was causing the new regalloc to fail.
Change-Id: If7ba7be38a436dbd0dd443828ddd7ebf6e35be0e
Reviewed-on: https://go-review.googlesource.com/13632
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Generating logging code every time causes large
diffs for small changes.
Since the intent is to use this for debugging only,
generate logging code only when requested.
Committed generated code will be logging free.
Change-Id: I9ef9e29c88b76c2557bad4c6b424b9db1255ec8b
Reviewed-on: https://go-review.googlesource.com/13623
Reviewed-by: Keith Randall <khr@golang.org>
Fix one test that build a violating CFG.
Change-Id: Ie0296ced602984d914a70461c76559c507ce2510
Reviewed-on: https://go-review.googlesource.com/13621
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
This makes it easier to investigate and
understand rewrite behavior.
Change-Id: I790e8964922caf98362ce8a6d6972f52d83eefa8
Reviewed-on: https://go-review.googlesource.com/13588
Reviewed-by: Keith Randall <khr@golang.org>
This claims to be autogenerated from go tool dist,
but I don't see where.
In any case, the update is trivial.
Change-Id: I58daaba755f3d34a0396005046b89411a02ada7e
Reviewed-on: https://go-review.googlesource.com/13584
Reviewed-by: Keith Randall <khr@golang.org>
We need to move the memory variable update back to before endBlock
so that all successors use the right memory value.
See https://go-review.googlesource.com/13560
Change-Id: Id72e5526c56e5e070b933d3b28dc503a5a2978dc
Reviewed-on: https://go-review.googlesource.com/13586
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Update #12108
If DUFFZERO is used within a tail call method it will overwrite the
link register.
Change-Id: I6abd2fde0f0ad909ccd55eb119b992673a74f0e2
Reviewed-on: https://go-review.googlesource.com/13570
Reviewed-by: Russ Cox <rsc@golang.org>
Fix the test broken with dee1f2 by implementing Elem()
Change-Id: I7a4a487885267c24fdc52d79fb7d450231328812
Reviewed-on: https://go-review.googlesource.com/13551
Reviewed-by: Keith Randall <khr@golang.org>
Consider OpZero to be a store so it can be eliminated by dse.
Change-Id: Idebb6a190657b76966f0c5b20f2ec9f52fe47499
Reviewed-on: https://go-review.googlesource.com/13447
Reviewed-by: Keith Randall <khr@golang.org>
Introduce pseudo-ops PanicMem and LoweredPanicMem.
PanicMem could be rewritten directly into MOVL
during lowering, but then we couldn't log nil checks.
With this change, runnable nil check tests pass:
GOSSAPKG=main go run run.go -- nil*.go
Compiler output nil check tests fail:
GOSSAPKG=p go run run.go -- nil*.go
This is due to several factors:
* SSA has improved elimination of unnecessary nil checks.
* SSA is missing elimination of implicit nil checks.
* SSA is missing extra logging about why nil checks were removed.
I'm not sure how best to resolve these failures,
particularly in a world in which the two backends
will live side by side for some time.
For now, punt on the problem.
Change-Id: Ib2ca6824551671f92e0e1800b036f5ca0905e2a3
Reviewed-on: https://go-review.googlesource.com/13474
Reviewed-by: Keith Randall <khr@golang.org>
We were not recording function calls as
changing the state of memory.
As a result, the scheduler was not aware that
storing values to the stack in order to make a
function call must happen *after* retrieving
results from the stack from a just-completed
function call.
This fixes the container/ring tests.
This was my first experience debugging an issue
using the HTML output. I'm feeling quite
pleased with it.
Change-Id: I9e8276846be9fd7a60422911b11816c5175e3d0a
Reviewed-on: https://go-review.googlesource.com/13560
Reviewed-by: Keith Randall <khr@golang.org>
Hardcoded the limit on constants only allowed.
Change-Id: Idb9b07b4871db7a752a79e492671e9b41207b956
Reviewed-on: https://go-review.googlesource.com/13257
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Move the known-non-nil scan outside the work loop to resolve an issue
with values that were declared outside the block being operated on.
Also consider phis whose arguments are all non-nil, as non-nil.
Change-Id: I4d5b840042de9eb181f2cb918f36913fb5d517a2
Reviewed-on: https://go-review.googlesource.com/13441
Reviewed-by: Keith Randall <khr@golang.org>
Use a version of Floyd's cycle finding algorithm,
but advance by 1 and 1/2 steps per cycle rather
than by 1 and 2. It is simpler and should be cheaper
in the normal, acyclic case.
This should fix the 386 and arm builds,
which are currently hung.
Change-Id: If8bd443011b28a5ecb004a549239991d3dfc862b
Reviewed-on: https://go-review.googlesource.com/13473
Reviewed-by: Keith Randall <khr@golang.org>
We must make sure that all loads that use a store are scheduled
before the next store. Add additional dependency edges to the
value graph to enforce this constraint.
Change-Id: Iab83644f68bc4c30637085b82ca7467b9d5513a5
Reviewed-on: https://go-review.googlesource.com/13470
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Don't nilcheck values that were constructed as a result of OpAddr or
OpAddPtr.
Change-Id: I38053e905d1b76a2a64e77f84e444d38a5217108
Reviewed-on: https://go-review.googlesource.com/13256
Reviewed-by: David Chase <drchase@google.com>
Rather than require an explicit Copy on the RHS of rewrite rules,
use rulegen magic to add it.
The advantages to handling this in rulegen are:
* simpler rules
* harder to accidentally miss a Copy
Change-Id: I46853bade83bdf517eee9495bf5a553175277b53
Reviewed-on: https://go-review.googlesource.com/13242
Reviewed-by: Keith Randall <khr@golang.org>
The lowering rules were missing the non-64 bit case.
SBBLcarrymask can be folded to a int32 integer whose
type has a smaller bit size. Without the new AND rules
the following would be generated:
v19 = MOVLconst <uint8> [-1] : SI
v20 = ANDB <uint8> v18 v19 : DI
which is obviously a NOP.
Fixes#12022
Change-Id: I5f4209f78edc0f118e5b9b2908739f09cefebca4
Reviewed-on: https://go-review.googlesource.com/13301
Reviewed-by: Keith Randall <khr@golang.org>
Make sure all referenced Blocks and Values are really there.
Fix deadcode to generate SSA graphs that pass this new test.
Change-Id: Ib002ce20e33490eb8c919bd189d209f769d61517
Reviewed-on: https://go-review.googlesource.com/13147
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
No functional changes.
The intent is just to make this
easier to read and maintain.
Change-Id: Iec207546482cd62bcb22eaae8efe5be6c4f15378
Reviewed-on: https://go-review.googlesource.com/13284
Reviewed-by: Keith Randall <khr@golang.org>
regalloc expects to find all OpSP and OpSB values
in the entry block.
There is no value to moving them; don't.
Change-Id: I775198f03ce7420348721ffc5e7d2bab065465b1
Reviewed-on: https://go-review.googlesource.com/13266
Reviewed-by: Keith Randall <khr@golang.org>
Given (say)
b1: <- b2 b3
v1 = Phi <t> v2 v3
b2:
v2 = ...
b3:
...
tighten will move v2 to b1, since it is only used in b1.
This is wrong; v2 needs to be evaluated before entering b1.
Fix it.
Change-Id: I2cc3b30e3ffd221cf594e36cec534dfd9cf3c6a7
Reviewed-on: https://go-review.googlesource.com/13264
Reviewed-by: Keith Randall <khr@golang.org>
Implement ITAB, selecting the itable field of an interface.
Soften the lowering check to allow lowerings that leave
generic but dead ops behind. (The ITAB lowering does this.)
Change-Id: Icc84961dd4060d143602f001311aa1d8be0d7fc0
Reviewed-on: https://go-review.googlesource.com/13144
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
I find myself always adding this in temporarily.
Make it permanent.
Change-Id: I1646b3930a07d0ea01840736ccd449b7fd24f06e
Reviewed-on: https://go-review.googlesource.com/13141
Reviewed-by: Keith Randall <khr@golang.org>
Failure to treat control ops as live can lead
to them being eliminated when they live in
other blocks.
Change-Id: I604a1977a3d3884b1f4516bea4e15885ce38272d
Reviewed-on: https://go-review.googlesource.com/13138
Reviewed-by: Keith Randall <khr@golang.org>
They were being omitted after scheduling.
Change-Id: Ia20e2dcb61fde9ec854918b958c3897bafd282a6
Reviewed-on: https://go-review.googlesource.com/13140
Reviewed-by: Keith Randall <khr@golang.org>
Don't put them in the control value's block.
That may be many blocks up the dominator tree.
Change-Id: Iab3ea36a890ffe0e355dadec7aeb676901c4f070
Reviewed-on: https://go-review.googlesource.com/13134
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
This is helpful when debugging generated code.
Change-Id: I268efa3593a03bb2c4e9f07d9034c004cd40df41
Reviewed-on: https://go-review.googlesource.com/13099
Reviewed-by: Keith Randall <khr@golang.org>
Rewrite ^{n}x to be ^{n % 2}x. This will eventually resolve a fuzz
issue that breaks v1.5.
Updates #11352
Change-Id: I1b3f93872d06222f9ff5f6fd5580178ebaf4c003
Reviewed-on: https://go-review.googlesource.com/13110
Reviewed-by: Keith Randall <khr@golang.org>
The DFS scheduler doesn't do the right thing. If a Value x is used by
more than one other Value, then x is put into the DFS queue when
its first user (call it y) is visited. It is not removed and reinserted
when the second user of x (call it z) is visited, so the dependency
between x and z is not respected. There is no easy way to fix this with
the DFS queue because we'd have to rip values out of the middle of the
DFS queue.
The new scheduler works from the end of the block backwards, scheduling
instructions which have had all of their uses already scheduled.
A simple priority scheme breaks ties between multiple instructions that
are ready to schedule simultaneously.
Keep track of whether we've scheduled or not, and make print() use
the scheduled order if we have.
Fix some shift tests that this change tickles. Add unsigned right shift tests.
Change-Id: I44164c10bb92ae8ab8f76d7a5180cbafab826ea1
Reviewed-on: https://go-review.googlesource.com/13069
Reviewed-by: Todd Neal <todd@tneal.org>
Modify tests to use a known value instead of comparing the backends
directly.
Change-Id: I32e804e12515885bd94c4f83644cbca03b018fea
Reviewed-on: https://go-review.googlesource.com/13042
Reviewed-by: Keith Randall <khr@golang.org>
On most systems, a pointer is the worst case alignment, so adding
a pointer field at the end of a struct guarantees there will be no
padding added after that field (to satisfy overall struct alignment
due to some more-aligned field also present).
In the runtime, the map implementation needs a quick way to
get to the overflow pointer, which is last in the bucket struct,
so it uses size - sizeof(pointer) as the offset.
NaCl/amd64p32 is the exception, as always.
The worst case alignment is 64 bits but pointers are 32 bits.
There's a long history that is not worth going into, but when
we moved the overflow pointer to the end of the struct,
we didn't get the padding computation right.
The compiler computed the regular struct size and then
on amd64p32 added another 32-bit field.
And the runtime assumed it could step back two 32-bit fields
(one 64-bit register size) to get to the overflow pointer.
But in fact if the struct needed 64-bit alignment, the computation
of the regular struct size would have added a 32-bit pad already,
and then the code unconditionally added a second 32-bit pad.
This placed the overflow pointer three words from the end, not two.
The last two were padding, and since the runtime was consistent
about using the second-to-last word as the overflow pointer,
no harm done in the sense of overwriting useful memory.
But writing the overflow pointer to a non-pointer word of memory
means that the GC can't see the overflow blocks, so it will
collect them prematurely. Then bad things happen.
Correct all this in a few steps:
1. Add an explicit check at the end of the bucket layout in the
compiler that the overflow field is last in the struct, never
followed by padding.
2. When padding is needed on nacl (not always, just when needed),
insert it before the overflow pointer, to preserve the "last in the struct"
property.
3. Let the compiler have the final word on the width of the struct,
by inserting an explicit padding field instead of overwriting the
results of the width computation it does.
4. For the same reason (tell the truth to the compiler), set the type
of the overflow field when we're trying to pretend its not a pointer
(in this case the runtime maintains a list of the overflow blocks
elsewhere).
5. Make the runtime use "last in the struct" as its location algorithm.
This fixes TestTraceStress on nacl/amd64p32.
The 'bad map state' and 'invalid free list' failures no longer occur.
Fixes#11838.
Change-Id: If918887f8f252d988db0a35159944d2b36512f92
Reviewed-on: https://go-review.googlesource.com/12971
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This fixes the crypto/subtle tests.
Change-Id: Ie6e721eec3481f67f13de1bfbd7988e227793148
Reviewed-on: https://go-review.googlesource.com/13000
Reviewed-by: Keith Randall <khr@golang.org>
The only types that remain in the ssa package
are special compiler-only types.
Change-Id: If957abf128ec0778910d67666c297f97f183b7ee
Reviewed-on: https://go-review.googlesource.com/12933
Reviewed-by: Keith Randall <khr@golang.org>
From compiling go there were 260 functions where XOR was needed.
Much of the required changes for implementing XOR were already
done in 12813.
Change-Id: I5a68aa028f5ed597bc1d62cedbef3620753dfe82
Reviewed-on: https://go-review.googlesource.com/12901
Reviewed-by: Keith Randall <khr@golang.org>
The existing backend simply elides OCONVNOP.
There's no reason for us to do any differently.
Rather than insert ConvNops and then rewrite them
away, stop creating them in the first place.
Change-Id: I4bcbe2229fcebd189ae18df24f2c612feb6e215e
Reviewed-on: https://go-review.googlesource.com/12810
Reviewed-by: Keith Randall <khr@golang.org>
Convert shift ops to also encode the size of the shift amount.
Change signed right shift from using CMOV to using bit twiddles.
It is a little bit better (5 instructions instead of 4, but fewer
bytes and slightly faster code). It's also a bit faster than
the 4-instruction branch version, even with a very predictable
branch. As tested on my machine, YMMV.
Implement OCOM while we are here.
Change-Id: I8ca12dd62fae5d626dc0e6da5d4bbd34fd9640d2
Reviewed-on: https://go-review.googlesource.com/12867
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
ODOTTYPE should be treated a whole lot like ODOT,
but it was missing completely from the switch in
escwalk and thus escape status did not propagate
to fields.
Since interfaces are required to trigger this bug,
the test was added to escape_iface.go.
Fixes#11931.
Change-Id: Id0383981cc4b1a160f6ad447192a112eed084538
Reviewed-on: https://go-review.googlesource.com/12921
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
Fixes arm64 builder crash.
The bug is possible on all architectures; you just have to get lucky
and hit a preemption or a stack growth on entry to assertE2I2.
The test stacks the deck.
Change-Id: I8419da909b06249b1ad15830cbb64e386b6aa5f6
Reviewed-on: https://go-review.googlesource.com/12890
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Lots and lots of ops!
Also XOR for good measure.
Add a pass to the compiler generator to check that all of the
architecture-specific opcodes are handled by genValue. We will
catch any missing ones if we come across them during compilation,
but probably better to catch them statically.
Change-Id: Ic4adfbec55c8257f88117bc732fa664486262868
Reviewed-on: https://go-review.googlesource.com/12813
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
If the compiler doesn't do it, cmd/internal/obj/arm64 will,
and that will break the zeroing of ambiguously live values
done in zerorange, which in turn produces uninitialized
pointer cells that the GC trips over.
For #9880.
Change-Id: Ice97c30bc8b36d06b7b88d778d87fab8e1827fdc
Reviewed-on: https://go-review.googlesource.com/12847
Reviewed-by: Austin Clements <austin@google.com>
From compiling go there were 761 functions where OR was needed.
Change-Id: Ied8bf59cec50a3175273387bc7416bd042def6d8
Reviewed-on: https://go-review.googlesource.com/12766
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
With this, all non-float, non-complex
binary ops found in the standard library
are implemented.
Change-Id: I6087f115229888c0dce10ab35db3fd36a0e0a8b1
Reviewed-on: https://go-review.googlesource.com/12799
Reviewed-by: Keith Randall <khr@golang.org>
Together with teaching SSA to generate static data,
this fixes the encoding/pem and hash/adler32 tests.
Change-Id: I75f81f6c995dcb9c6d99bd3acda94a4feea8b87b
Reviewed-on: https://go-review.googlesource.com/12791
Reviewed-by: Keith Randall <khr@golang.org>
The existing backend recognizes special
assignment statements as being implementable
with static data rather than code.
Unfortunately, it assumes that it is in the middle
of codegen; it emits data and modifies the AST.
This does not play well with SSA's two-phase
bootstrapping approach, in which we attempt to
compile code but fall back to the existing backend
if something goes wrong.
To work around this:
* Add the ability to inquire about static data
without side-effects.
* Save the static data required for a function.
* Emit that static data during SSA codegen.
Change-Id: I2e8a506c866ea3e27dffb597095833c87f62d87e
Reviewed-on: https://go-review.googlesource.com/12790
Reviewed-by: Keith Randall <khr@golang.org>
For integer types less than a machine register, we have to decide
what the invariants are for the high bits of the register. We used
to set the high bits to the correct extension (sign or zero, as
determined by the type) of the low bits.
This CL makes the compiler ignore the high bits of the register
altogether (they are junk).
On this plus side, this means ops that generate subword results don't
have to worry about correctly extending them. On the minus side,
ops that consume subword arguments have to deal with the input
registers not being correctly extended.
For x86, this tradeoff is probably worth it. Almost all opcodes
have versions that use only the correct subword piece of their
inputs. (The one big exception is array indexing.) Not many opcodes
can correctly sign extend on output.
For other architectures, the tradeoff is probably not so clear, as
they don't have many subword-safe opcodes (e.g. 16-bit compare,
ignoring the high 16/48 bits). Fortunately we can decide whether
we do this per-architecture.
For the machine-independent opcodes, we pretend that the "register"
size is equal to the type width, so sign extension is immaterial.
Opcodes that care about the signedness of the input (e.g. compare,
right shift) have two different variants.
Change-Id: I465484c5734545ee697afe83bc8bf4b53bd9df8d
Reviewed-on: https://go-review.googlesource.com/12600
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
The only slice/interface comparisons that reach
the backend are comparisons to nil.
Funcs, maps, and channels are references types,
so pointer equality is enough.
Change-Id: I60a71da46a36202e9bd62ed370ab7d7f2e2800e7
Reviewed-on: https://go-review.googlesource.com/12715
Reviewed-by: Keith Randall <khr@golang.org>
Before this patch there was only partial support for ANDQconst
which was not lowered. This patch added support for AND operations
for all bit sizes and signs.
Change-Id: I3a6b2cddfac5361b27e85fcd97f7f3537ebfbcb6
Reviewed-on: https://go-review.googlesource.com/12761
Reviewed-by: Keith Randall <khr@golang.org>
Rules may span multiple lines,
but if we're still unbalanced at the
end of the file, something is wrong.
I write unbalanced rules depressingly often.
Change-Id: Ibd04aa06539e2a0ffef73bb665febf3542fd11f1
Reviewed-on: https://go-review.googlesource.com/12710
Reviewed-by: Keith Randall <khr@golang.org>
This mimics the way the old backend
compiles OCALLMETH.
Change-Id: I635c8e7a48c8b5619bd837f78fa6eeba83a57b2f
Reviewed-on: https://go-review.googlesource.com/12549
Reviewed-by: Keith Randall <khr@golang.org>
If flushing a value from a register that might be used by the current
old-schedule value, save it to the home location.
This resolves the error that was changed from panic to unimplemented in
CL 12655.
Change-Id: If864be34abcd6e11d6117a061376e048a3e29b3a
Reviewed-on: https://go-review.googlesource.com/12682
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Some of these were right; others weren't.
Fixes 'GOGC=off GOSSAPKG=mime go test -a mime'.
The right long term fix is probably to teach the
register allocator about in-place instructions.
In the meantime, all the tests that we can run
now pass.
Change-Id: I8e37b00a5f5e14f241b427d45d5f5cc1064883a2
Reviewed-on: https://go-review.googlesource.com/12664
Reviewed-by: Keith Randall <khr@golang.org>
Prior to this, we were smashing our own stack,
which caused the crypto/sha256 tests to fail.
Change-Id: I7dd94cf466d175b3be0cd65f9c4fe8b1223081fe
Reviewed-on: https://go-review.googlesource.com/12660
Reviewed-by: Daniel Morsing <daniel.morsing@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
Fix an issue where doasm fails if trying to multiply by a larger
than 32 bit const (doasm: notfound ft=9 tt=14 00008 IMULQ
$34359738369, CX 9 14). Fix truncation of 64 to 32 bit integer
when generating LEA causing incorrect values to be computed.
Change-Id: I1e65b63cc32ac673a9bb5a297b578b44c2f1ac8f
Reviewed-on: https://go-review.googlesource.com/12678
Reviewed-by: Keith Randall <khr@golang.org>
Rewrite if !cond by swapping the branches and removing the not.
Change-Id: If3af1bac02bfc566faba872a8c7f7e5ce38e9f58
Reviewed-on: https://go-review.googlesource.com/12610
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
This prevents panics while attempting to generate code
for the runtime package. Now:
<unknown line number>: internal compiler error: localOffset of non-LocalSlot value: v10 = ADDQconst <*m> [256] v22
Change-Id: I20ed6ec6aae2c91183b8c826b8ebcc98e8ceebff
Reviewed-on: https://go-review.googlesource.com/12655
Reviewed-by: Keith Randall <khr@golang.org>