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cmd/compile: move duffcopy auxint calculation out of rewrite rules

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Package amd64 is a more natural home for it.
It also makes it easier to see how many bytes
are being copied in ssa.html.

Passes toolstash-check.

Change-Id: I5ecf0f0f18e8db2faa2caf7a05028c310952bd94
Reviewed-on: https://go-review.googlesource.com/c/go/+/229703
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Josh Bleecher Snyder 2020-04-23 13:11:00 -07:00
parent b0a8754475
commit b3e8a00060
4 changed files with 14 additions and 11 deletions
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11
src/cmd/compile/internal/amd64/ssa.go
View File

@ -872,7 +872,16 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
p := s.Prog(obj.ADUFFCOPY)
p.To.Type = obj.TYPE_ADDR
p.To.Sym = gc.Duffcopy
p.To.Offset = v.AuxInt
if v.AuxInt%16 != 0 {
v.Fatalf("bad DUFFCOPY AuxInt %v", v.AuxInt)
}
p.To.Offset = 14 * (64 - v.AuxInt/16)
// 14 and 64 are magic constants. 14 is the number of bytes to encode:
// MOVUPS (SI), X0
// ADDQ $16, SI
// MOVUPS X0, (DI)
// ADDQ $16, DI
// and 64 is the number of such blocks. See src/runtime/duff_amd64.s:duffcopy.
case ssa.OpCopy: // TODO: use MOVQreg for reg->reg copies instead of OpCopy?
if v.Type.IsMemory() {

8
src/cmd/compile/internal/ssa/gen/AMD64.rules
View File

@ -309,13 +309,7 @@
(Move [s] dst src mem)
&& s > 64 && s <= 16*64 && s%16 == 0
&& !config.noDuffDevice && logLargeCopy(v, s) =>
(DUFFCOPY [14*(64-s/16)] dst src mem)
// 14 and 64 are magic constants. 14 is the number of bytes to encode:
// MOVUPS (SI), X0
// ADDQ $16, SI
// MOVUPS X0, (DI)
// ADDQ $16, DI
// and 64 is the number of such blocks. See src/runtime/duff_amd64.s:duffcopy.
(DUFFCOPY [s] dst src mem)
// Large copying uses REP MOVSQ.
(Move [s] dst src mem) && (s > 16*64 || config.noDuffDevice) && s%8 == 0 && logLargeCopy(v, s) =>

2
src/cmd/compile/internal/ssa/gen/AMD64Ops.go
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@ -681,7 +681,7 @@ func init() {
// arg0 = destination pointer
// arg1 = source pointer
// arg2 = mem
// auxint = offset from duffcopy symbol to call
// auxint = # of bytes to copy, must be multiple of 16
// returns memory
{
name: "DUFFCOPY",

4
src/cmd/compile/internal/ssa/rewriteAMD64.go
View File

@ -31641,7 +31641,7 @@ func rewriteValueAMD64_OpMove(v *Value) bool {
}
// match: (Move [s] dst src mem)
// cond: s > 64 && s <= 16*64 && s%16 == 0 && !config.noDuffDevice && logLargeCopy(v, s)
// result: (DUFFCOPY [14*(64-s/16)] dst src mem)
// result: (DUFFCOPY [s] dst src mem)
for {
s := auxIntToInt64(v.AuxInt)
dst := v_0
@ -31651,7 +31651,7 @@ func rewriteValueAMD64_OpMove(v *Value) bool {
break
}
v.reset(OpAMD64DUFFCOPY)
v.AuxInt = int64ToAuxInt(14 * (64 - s/16))
v.AuxInt = int64ToAuxInt(s)
v.AddArg3(dst, src, mem)
return true
}