cmd/compile: remove bit operations that modify memory directly

These operations (BT{S,R,C}{Q,L}modify) are quite a bit slower than
other ways of doing the same thing.

Without the BTxmodify operations, there are two fallback ways the compiler
performs these operations: AND/OR/XOR operations directly on memory, or
load-BTx-write sequences. The compiler kinda chooses one arbitrarily
depending on rewrite rule application order. Currently, it uses
load-BTx-write for the Const benchmarks and AND/OR/XOR directly to memory
for the non-Const benchmarks. TBD, someone might investigate which of
the two fallback strategies is really better. For now, they are both
better than BTx ops.

name              old time/op  new time/op  delta
BitSet-8          1.09µs ± 2%  0.64µs ± 5%  -41.60%  (p=0.000 n=9+10)
BitClear-8        1.15µs ± 3%  0.68µs ± 6%  -41.00%  (p=0.000 n=10+10)
BitToggle-8       1.18µs ± 4%  0.73µs ± 2%  -38.36%  (p=0.000 n=10+8)
BitSetConst-8     37.0ns ± 7%  25.8ns ± 2%  -30.24%  (p=0.000 n=10+10)
BitClearConst-8   30.7ns ± 2%  25.0ns ±12%  -18.46%  (p=0.000 n=10+10)
BitToggleConst-8  36.9ns ± 1%  23.8ns ± 3%  -35.46%  (p=0.000 n=9+10)

Fixes #45790
Update #45242

Change-Id: Ie33a72dc139f261af82db15d446cd0855afb4e59
Reviewed-on: https://go-review.googlesource.com/c/go/+/318149
Trust: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ben Shi <powerman1st@163.com>

1 files changed, 0 insertions, 186 deletions

diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index 51cb0881b8..1c37fbe0db 100644
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -692,18 +692,6 @@ const (
 	OpAMD64BTRQconst
 	OpAMD64BTSLconst
 	OpAMD64BTSQconst
-	OpAMD64BTCQmodify
-	OpAMD64BTCLmodify
-	OpAMD64BTSQmodify
-	OpAMD64BTSLmodify
-	OpAMD64BTRQmodify
-	OpAMD64BTRLmodify
-	OpAMD64BTCQconstmodify
-	OpAMD64BTCLconstmodify
-	OpAMD64BTSQconstmodify
-	OpAMD64BTSLconstmodify
-	OpAMD64BTRQconstmodify
-	OpAMD64BTRLconstmodify
 	OpAMD64TESTQ
 	OpAMD64TESTL
 	OpAMD64TESTW
@@ -8522,180 +8510,6 @@ var opcodeTable = [...]opInfo{
 		},
 	},
 	{
-		name:           "BTCQmodify",
-		auxType:        auxSymOff,
-		argLen:         3,
-		clobberFlags:   true,
-		faultOnNilArg0: true,
-		symEffect:      SymRead | SymWrite,
-		asm:            x86.ABTCQ,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{1, 49151},      // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 R15
-				{0, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 g R15 SB
-			},
-		},
-	},
-	{
-		name:           "BTCLmodify",
-		auxType:        auxSymOff,
-		argLen:         3,
-		clobberFlags:   true,
-		faultOnNilArg0: true,
-		symEffect:      SymRead | SymWrite,
-		asm:            x86.ABTCL,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{1, 49151},      // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 R15
-				{0, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 g R15 SB
-			},
-		},
-	},
-	{
-		name:           "BTSQmodify",
-		auxType:        auxSymOff,
-		argLen:         3,
-		clobberFlags:   true,
-		faultOnNilArg0: true,
-		symEffect:      SymRead | SymWrite,
-		asm:            x86.ABTSQ,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{1, 49151},      // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 R15
-				{0, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 g R15 SB
-			},
-		},
-	},
-	{
-		name:           "BTSLmodify",
-		auxType:        auxSymOff,
-		argLen:         3,
-		clobberFlags:   true,
-		faultOnNilArg0: true,
-		symEffect:      SymRead | SymWrite,
-		asm:            x86.ABTSL,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{1, 49151},      // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 R15
-				{0, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 g R15 SB
-			},
-		},
-	},
-	{
-		name:           "BTRQmodify",
-		auxType:        auxSymOff,
-		argLen:         3,
-		clobberFlags:   true,
-		faultOnNilArg0: true,
-		symEffect:      SymRead | SymWrite,
-		asm:            x86.ABTRQ,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{1, 49151},      // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 R15
-				{0, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 g R15 SB
-			},
-		},
-	},
-	{
-		name:           "BTRLmodify",
-		auxType:        auxSymOff,
-		argLen:         3,
-		clobberFlags:   true,
-		faultOnNilArg0: true,
-		symEffect:      SymRead | SymWrite,
-		asm:            x86.ABTRL,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{1, 49151},      // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 R15
-				{0, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 g R15 SB
-			},
-		},
-	},
-	{
-		name:           "BTCQconstmodify",
-		auxType:        auxSymValAndOff,
-		argLen:         2,
-		clobberFlags:   true,
-		faultOnNilArg0: true,
-		symEffect:      SymRead | SymWrite,
-		asm:            x86.ABTCQ,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{0, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 g R15 SB
-			},
-		},
-	},
-	{
-		name:           "BTCLconstmodify",
-		auxType:        auxSymValAndOff,
-		argLen:         2,
-		clobberFlags:   true,
-		faultOnNilArg0: true,
-		symEffect:      SymRead | SymWrite,
-		asm:            x86.ABTCL,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{0, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 g R15 SB
-			},
-		},
-	},
-	{
-		name:           "BTSQconstmodify",
-		auxType:        auxSymValAndOff,
-		argLen:         2,
-		clobberFlags:   true,
-		faultOnNilArg0: true,
-		symEffect:      SymRead | SymWrite,
-		asm:            x86.ABTSQ,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{0, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 g R15 SB
-			},
-		},
-	},
-	{
-		name:           "BTSLconstmodify",
-		auxType:        auxSymValAndOff,
-		argLen:         2,
-		clobberFlags:   true,
-		faultOnNilArg0: true,
-		symEffect:      SymRead | SymWrite,
-		asm:            x86.ABTSL,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{0, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 g R15 SB
-			},
-		},
-	},
-	{
-		name:           "BTRQconstmodify",
-		auxType:        auxSymValAndOff,
-		argLen:         2,
-		clobberFlags:   true,
-		faultOnNilArg0: true,
-		symEffect:      SymRead | SymWrite,
-		asm:            x86.ABTRQ,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{0, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 g R15 SB
-			},
-		},
-	},
-	{
-		name:           "BTRLconstmodify",
-		auxType:        auxSymValAndOff,
-		argLen:         2,
-		clobberFlags:   true,
-		faultOnNilArg0: true,
-		symEffect:      SymRead | SymWrite,
-		asm:            x86.ABTRL,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{0, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 g R15 SB
-			},
-		},
-	},
-	{
 		name:        "TESTQ",
 		argLen:      2,
 		commutative: true,