Add label and goto checks and improve test coverage.
Implement OSWITCH and OSELECT.
Implement OBREAK and OCONTINUE.
Allow generation of code in dead blocks.
Change-Id: Ibebb7c98b4b2344f46d38db7c9dce058c56beaac
Reviewed-on: https://go-review.googlesource.com/12445
Reviewed-by: Keith Randall <khr@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/12004
Reviewed-by: Todd Neal <todd@tneal.org>
Reviewed-by: Michael Matloob <michaelmatloob@gmail.com>
The nilcheckelim pass eliminates unnecessary nil checks.
The initial implementation removes redundant nil checks.
See the comments in nilcheck.go for ideas for future
improvements.
The efficacy of the cse pass has a significant impact
on this efficacy of this pass.
There are 886 nil checks in the parts of the standard
library that SSA can currently compile (~20%).
This pass eliminates 75 (~8.5%) of them.
As a data point, with a more aggressive but unsound
cse pass that treats many more types as identical,
this pass eliminates 115 (~13%) of the nil checks.
Change-Id: I13e567a39f5f6909fc33434d55c17a7e3884a704
Reviewed-on: https://go-review.googlesource.com/11430
Reviewed-by: Alan Donovan <adonovan@google.com>
The SSA implementation logs for three purposes:
* debug logging
* fatal errors
* unimplemented features
Separating these three uses lets us attempt an SSA
implementation for all functions, not just
_ssa functions. This turns the entire standard
library into a compilation test, and makes it
easy to figure out things like
"how much coverage does SSA have now" and
"what should we do next to get more coverage?".
Functions called _ssa are still special.
They log profusely by default and
the output of the SSA implementation
is used. For all other functions,
logging is off, and the implementation
is built and discarded, due to lack of
support for the runtime.
While we're here, fix a few minor bugs and
add some extra Unimplementeds to allow
all.bash to pass.
As of now, SSA handles 20.79% of the functions
in the standard library (689 of 3314).
The top missing features are:
10.03% 2597 SSA unimplemented: zero for type error not implemented
7.79% 2016 SSA unimplemented: addr: bad op DOTPTR
7.33% 1898 SSA unimplemented: unhandled expr EQ
6.10% 1579 SSA unimplemented: unhandled expr OROR
4.91% 1271 SSA unimplemented: unhandled expr NE
4.49% 1163 SSA unimplemented: unhandled expr LROT
4.00% 1036 SSA unimplemented: unhandled expr LEN
3.56% 923 SSA unimplemented: unhandled stmt CALLFUNC
2.37% 615 SSA unimplemented: zero for type []byte not implemented
1.90% 492 SSA unimplemented: unhandled stmt CALLMETH
1.74% 450 SSA unimplemented: unhandled expr CALLINTER
1.74% 450 SSA unimplemented: unhandled expr DOT
1.71% 444 SSA unimplemented: unhandled expr ANDAND
1.65% 426 SSA unimplemented: unhandled expr CLOSUREVAR
1.54% 400 SSA unimplemented: unhandled expr CALLMETH
1.51% 390 SSA unimplemented: unhandled stmt SWITCH
1.47% 380 SSA unimplemented: unhandled expr CONV
1.33% 345 SSA unimplemented: addr: bad op *
1.30% 336 SSA unimplemented: unhandled OLITERAL 6
Change-Id: I4ca07951e276714dc13c31de28640aead17a1be7
Reviewed-on: https://go-review.googlesource.com/11160
Reviewed-by: Keith Randall <khr@golang.org>
Eliminate dead stores. Dead stores are those which are
unconditionally followed by another store to the same location, with
no intervening load.
Just a simple intra-block implementation for now.
Change-Id: I2bf54e3a342608fc4e01edbe1b429e83f24764ab
Reviewed-on: https://go-review.googlesource.com/10386
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Code generation is now done in genssa.
Also remove the asm field in opInfo. It's no longer used.
Change-Id: I65fffac267e138fd424b2ef8aa7ed79f0ebb63d5
Reviewed-on: https://go-review.googlesource.com/10539
Reviewed-by: Keith Randall <khr@golang.org>
Semi-regular merge of tip to dev.ssa.
Complicated a bit by the move of cmd/internal/* to cmd/compile/internal/*.
Change-Id: I1c66d3c29bb95cce4a53c5a3476373aa5245303d
