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ba6bd967d2
The current phiopt pass just transforms the following code
x := false
if b { x = true}
into
x = b
But we find code in runtime.atoi like this:
neg := false
if s[0] == '-' {
neg = true
s = s[1:]
}
The current phiopt pass does not covert it into code like:
neg := s[0] == '-'
if neg { s = s[1:] }
Therefore, this patch strengthens the phiopt pass so that the
boolean Phi value "neg" can be replaced with a copy of control
value "s[0] == '-'", thereby using "cmp+cset" instead of a branch.
But in some cases even replacing the boolean Phis cannot eliminate
this branch. In the following case, this patch replaces "d" with a
copy of "a<0", but the regalloc pass will insert the "Load {c}"
value into an empty block to split the live ranges, which causes
the branch to not be eliminated.
For example:
func test(a, b, c int) (bool, int) {
d := false
if (a<0) {
if (b<0) {
c = c+1
}
d = true
}
return d, c
}
The optimized assembly code:
MOVD "".a(FP), R0
TBZ $63, R0, 48
MOVD "".c+16(FP), R1
ADD $1, R1, R2
MOVD "".b+8(FP), R3
CMP ZR, R3
CSEL LT, R2, R1, R1
CMP ZR, R0
CSET LT, R0
MOVB R0, "".~r3+24(FP)
MOVD R1, "".~r4+32(FP)
RET (R30)
MOVD "".c+16(FP), R1
JMP 28
The benchmark:
name old time/op new time/op delta
pkg:cmd/compile/internal/ssa goos:linux goarch:arm64
PhioptPass 117783.250000ns +- 1% 117219.111111ns +- 1% ~ (p=0.074 n=8+9)
Statistical data from compilecmp tool:
compilecmp local/master -> HEAD
local/master (
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| .. | ||
| abi | ||
| alias3.dir | ||
| bench | ||
| chan | ||
| closure3.dir | ||
| closure5.dir | ||
| codegen | ||
| ddd2.dir | ||
| dwarf | ||
| fixedbugs | ||
| import2.dir | ||
| import4.dir | ||
| interface | ||
| intrinsic.dir | ||
| ken | ||
| linkname.dir | ||
| method4.dir | ||
| oldescape_linkname.dir | ||
| retjmp.dir | ||
| runtime | ||
| stress | ||
| syntax | ||
| typeparam | ||
| uintptrescapes.dir | ||
| 64bit.go | ||
| 235.go | ||
| alg.go | ||
| alias1.go | ||
| alias2.go | ||
| alias3.go | ||
| alias.go | ||
| align.go | ||
| append1.go | ||
| append.go | ||
| args.go | ||
| armimm.go | ||
| assign1.go | ||
| assign.go | ||
| atomicload.go | ||
| bigalg.go | ||
| bigmap.go | ||
| blank1.go | ||
| blank.go | ||
| bom.go | ||
| bombad.go | ||
| bounds.go | ||
| cannotassign.go | ||
| chancap.go | ||
| chanlinear.go | ||
| char_lit1.go | ||
| char_lit.go | ||
| checkbce.go | ||
| clearfat.go | ||
| closedchan.go | ||
| closure1.go | ||
| closure2.go | ||
| closure3.go | ||
| closure4.go | ||
| closure5.go | ||
| closure6.go | ||
| closure7.go | ||
| closure.go | ||
| cmp6.go | ||
| cmp.go | ||
| cmplx.go | ||
| cmplxdivide1.go | ||
| cmplxdivide.c | ||
| cmplxdivide.go | ||
| complit1.go | ||
| complit.go | ||
| compos.go | ||
| const1.go | ||
| const2.go | ||
| const3.go | ||
| const4.go | ||
| const5.go | ||
| const6.go | ||
| const7.go | ||
| const.go | ||
| convert1.go | ||
| convert2.go | ||
| convert3.go | ||
| convert.go | ||
| convlit1.go | ||
| convlit.go | ||
| convT2X.go | ||
| copy1.go | ||
| copy.go | ||
| crlf.go | ||
| ddd1.go | ||
| ddd2.go | ||
| ddd.go | ||
| decl.go | ||
| declbad.go | ||
| defer.go | ||
| defererrcheck.go | ||
| deferfin.go | ||
| defernil.go | ||
| deferprint.go | ||
| deferprint.out | ||
| devirt.go | ||
| directive.go | ||
| divide.go | ||
| divmod.go | ||
| embedfunc.go | ||
| embedvers.go | ||
| empty.go | ||
| env.go | ||
| eof1.go | ||
| eof.go | ||
| escape2.go | ||
| escape2n.go | ||
| escape3.go | ||
| escape4.go | ||
| escape5.go | ||
| escape_array.go | ||
| escape_calls.go | ||
| escape_closure.go | ||
| escape_field.go | ||
| escape_goto.go | ||
| escape_hash_maphash.go | ||
| escape_iface.go | ||
| escape_indir.go | ||
| escape_level.go | ||
| escape_map.go | ||
| escape_param.go | ||
| escape_runtime_atomic.go | ||
| escape_selfassign.go | ||
| escape_slice.go | ||
| escape_struct_param1.go | ||
| escape_struct_param2.go | ||
| escape_struct_return.go | ||
| escape_sync_atomic.go | ||
| escape_unsafe.go | ||
| escape.go | ||
| fibo.go | ||
| finprofiled.go | ||
| float_lit2.go | ||
| float_lit3.go | ||
| float_lit.go | ||
| floatcmp.go | ||
| for.go | ||
| func1.go | ||
| func2.go | ||
| func3.go | ||
| func4.go | ||
| func5.go | ||
| func6.go | ||
| func7.go | ||
| func8.go | ||
| func.go | ||
| funcdup2.go | ||
| funcdup.go | ||
| gc1.go | ||
| gc2.go | ||
| gc.go | ||
| gcgort.go | ||
| gcstring.go | ||
| goprint.go | ||
| goprint.out | ||
| goto.go | ||
| heapsampling.go | ||
| helloworld.go | ||
| helloworld.out | ||
| if.go | ||
| import1.go | ||
| import2.go | ||
| import4.go | ||
| import5.go | ||
| import6.go | ||
| import.go | ||
| index0.go | ||
| index1.go | ||
| index2.go | ||
| index.go | ||
| indirect1.go | ||
| indirect.go | ||
| init1.go | ||
| init.go | ||
| initcomma.go | ||
| initempty.go | ||
| initexp.go | ||
| initialize.go | ||
| initializerr.go | ||
| initloop.go | ||
| inline_big.go | ||
| inline_caller.go | ||
| inline_callers.go | ||
| inline_literal.go | ||
| inline_math_bits_rotate.go | ||
| inline_sync.go | ||
| inline_variadic.go | ||
| inline.go | ||
| int_lit.go | ||
| intcvt.go | ||
| intrinsic_atomic.go | ||
| intrinsic.go | ||
| iota.go | ||
| label1.go | ||
| label.go | ||
| linkmain_run.go | ||
| linkmain.go | ||
| linkname2.go | ||
| linkname.go | ||
| linkobj.go | ||
| linkx_run.go | ||
| linkx.go | ||
| literal2.go | ||
| literal.go | ||
| live1.go | ||
| live2.go | ||
| live_syscall.go | ||
| live.go | ||
| locklinear.go | ||
| loopbce.go | ||
| mainsig.go | ||
| makechan.go | ||
| makemap.go | ||
| makenew.go | ||
| makeslice.go | ||
| mallocfin.go | ||
| map1.go | ||
| map.go | ||
| mapclear.go | ||
| maplinear.go | ||
| mergemul.go | ||
| method1.go | ||
| method2.go | ||
| method3.go | ||
| method4.go | ||
| method5.go | ||
| method6.go | ||
| method7.go | ||
| method.go | ||
| named1.go | ||
| named.go | ||
| nil.go | ||
| nilcheck.go | ||
| nilptr2.go | ||
| nilptr3.go | ||
| nilptr4.go | ||
| nilptr5_aix.go | ||
| nilptr5_wasm.go | ||
| nilptr5.go | ||
| nilptr_aix.go | ||
| nilptr.go | ||
| nosplit.go | ||
| notinheap2.go | ||
| notinheap3.go | ||
| notinheap.go | ||
| nowritebarrier.go | ||
| nul1.go | ||
| opt_branchlikely.go | ||
| parentype.go | ||
| peano.go | ||
| phiopt.go | ||
| print.go | ||
| print.out | ||
| printbig.go | ||
| printbig.out | ||
| prove.go | ||
| range.go | ||
| README.md | ||
| recover1.go | ||
| recover2.go | ||
| recover3.go | ||
| recover4.go | ||
| recover5.go | ||
| recover.go | ||
| reflectmethod1.go | ||
| reflectmethod2.go | ||
| reflectmethod3.go | ||
| reflectmethod4.go | ||
| reflectmethod5.go | ||
| reflectmethod6.go | ||
| reflectmethod7.go | ||
| rename1.go | ||
| rename.go | ||
| reorder2.go | ||
| reorder.go | ||
| retjmp.go | ||
| return.go | ||
| rotate0.go | ||
| rotate1.go | ||
| rotate2.go | ||
| rotate3.go | ||
| rotate.go | ||
| run.go | ||
| rune.go | ||
| runtime.go | ||
| shift1.go | ||
| shift2.go | ||
| sieve.go | ||
| sigchld.go | ||
| sigchld.out | ||
| simassign.go | ||
| sinit_run.go | ||
| sinit.go | ||
| sizeof.go | ||
| slice3.go | ||
| slice3err.go | ||
| slicecap.go | ||
| sliceopt.go | ||
| solitaire.go | ||
| stack.go | ||
| stackobj2.go | ||
| stackobj3.go | ||
| stackobj.go | ||
| strcopy.go | ||
| strength.go | ||
| string_lit.go | ||
| stringrange.go | ||
| struct0.go | ||
| switch2.go | ||
| switch3.go | ||
| switch4.go | ||
| switch5.go | ||
| switch6.go | ||
| switch7.go | ||
| switch.go | ||
| tinyfin.go | ||
| torture.go | ||
| turing.go | ||
| typecheck.go | ||
| typecheckloop.go | ||
| typeswitch1.go | ||
| typeswitch2.go | ||
| typeswitch2b.go | ||
| typeswitch3.go | ||
| typeswitch.go | ||
| uintptrescapes2.go | ||
| uintptrescapes3.go | ||
| uintptrescapes.go | ||
| undef.go | ||
| used.go | ||
| utf.go | ||
| varerr.go | ||
| varinit.go | ||
| winbatch.go | ||
| writebarrier.go | ||
| zerodivide.go | ||
The test directory contains tests of the Go tool chain and runtime. It includes black box tests, regression tests, and error output tests. They are run as part of all.bash.
To run just these tests, execute:
../bin/go run run.go
To run just tests from specified files in this directory, execute:
../bin/go run run.go -- file1.go file2.go ...
Standard library tests should be written as regular Go tests in the appropriate package.
The tool chain and runtime also have regular Go tests in their packages. The main reasons to add a new test to this directory are:
- it is most naturally expressed using the test runner; or
- it is also applicable to
gccgoand other Go tool chains.