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cmd/compile: optimize 386's math.bits.TrailingZeros16

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This CL reverts CL 192097 and fixes the issue in CL 189277.

Change-Id: Icd271262e1f5019a8e01c91f91c12c1261eeb02b
Reviewed-on: https://go-review.googlesource.com/c/go/+/192519
Run-TryBot: Ben Shi <powerman1st@163.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Ben Shi 2019-08-30 06:24:58 +00:00 committed by Daniel Martí
parent ba068c1a6f
commit 8d5197d818
4 changed files with 36 additions and 1 deletions
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2
src/cmd/compile/internal/gc/ssa.go
View File

@ -3370,7 +3370,7 @@ func init() {
func(s *state, n *Node, args []*ssa.Value) *ssa.Value {
return s.newValue1(ssa.OpCtz16, types.Types[TINT], args[0])
},
sys.AMD64, sys.ARM, sys.ARM64, sys.Wasm)
sys.AMD64, sys.I386, sys.ARM, sys.ARM64, sys.Wasm)
addF("math/bits", "TrailingZeros16",
func(s *state, n *Node, args []*ssa.Value) *ssa.Value {
x := s.newValue1(ssa.OpZeroExt16to64, types.Types[TUINT64], args[0])

3
src/cmd/compile/internal/ssa/gen/386.rules
View File

@ -66,6 +66,9 @@
(Sqrt x) -> (SQRTSD x)
(Ctz16 x) -> (BSFL (ORLconst <typ.UInt32> [0x10000] x))
(Ctz16NonZero x) -> (BSFL x)
// Lowering extension
(SignExt8to16 x) -> (MOVBLSX x)
(SignExt8to32 x) -> (MOVBLSX x)

31
src/cmd/compile/internal/ssa/rewrite386.go
View File

@ -360,6 +360,10 @@ func rewriteValue386(v *Value) bool {
return rewriteValue386_OpConstBool_0(v)
case OpConstNil:
return rewriteValue386_OpConstNil_0(v)
case OpCtz16:
return rewriteValue386_OpCtz16_0(v)
case OpCtz16NonZero:
return rewriteValue386_OpCtz16NonZero_0(v)
case OpCvt32Fto32:
return rewriteValue386_OpCvt32Fto32_0(v)
case OpCvt32Fto64F:
@ -20783,6 +20787,33 @@ func rewriteValue386_OpConstNil_0(v *Value) bool {
return true
}
}
func rewriteValue386_OpCtz16_0(v *Value) bool {
b := v.Block
typ := &b.Func.Config.Types
// match: (Ctz16 x)
// cond:
// result: (BSFL (ORLconst <typ.UInt32> [0x10000] x))
for {
x := v.Args[0]
v.reset(Op386BSFL)
v0 := b.NewValue0(v.Pos, Op386ORLconst, typ.UInt32)
v0.AuxInt = 0x10000
v0.AddArg(x)
v.AddArg(v0)
return true
}
}
func rewriteValue386_OpCtz16NonZero_0(v *Value) bool {
// match: (Ctz16NonZero x)
// cond:
// result: (BSFL x)
for {
x := v.Args[0]
v.reset(Op386BSFL)
v.AddArg(x)
return true
}
}
func rewriteValue386_OpCvt32Fto32_0(v *Value) bool {
// match: (Cvt32Fto32 x)
// cond:

1
test/codegen/mathbits.go
View File

@ -298,6 +298,7 @@ func TrailingZeros32(n uint32) int {
func TrailingZeros16(n uint16) int {
// amd64:"BSFL","BTSL\\t\\$16"
// 386:"BSFL\t"
// arm:"ORR\t\\$65536","CLZ",-"MOVHU\tR"
// arm64:"ORR\t\\$65536","RBITW","CLZW",-"MOVHU\tR",-"RBIT\t",-"CLZ\t"
// s390x:"FLOGR","OR\t\\$65536"