cmd/compile: remove traces of old register allocator

Only added lines are moving amd64 and x86's ginsnop functions from
gsubr.go to ggen.go to match other architectures, so all of the
gsubr.go files can go away.

Change-Id: Ib2292460c155ae6d9dcf5c9801f178031d8eea7a
Reviewed-on: https://go-review.googlesource.com/29240
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>

src/cmd/compile/internal/amd64/galign.go

@@ -18,13 +18,6 @@ func betypeinit() {
 	if obj.GOARCH == "amd64p32" {
 		leaptr = x86.ALEAL
 	}
-	if gc.Ctxt.Flag_dynlink || obj.GOOS == "nacl" {
-		resvd = append(resvd, x86.REG_R15)
-	}
-	if gc.Ctxt.Framepointer_enabled || obj.GOOS == "nacl" {
-		resvd = append(resvd, x86.REG_BP)
-	}
-	gc.Thearch.ReservedRegs = resvd
 }
 
 func Main() {
@@ -34,13 +27,6 @@ func Main() {
 	}
 	gc.Thearch.REGSP = x86.REGSP
 	gc.Thearch.REGCTXT = x86.REGCTXT
-	gc.Thearch.REGCALLX = x86.REG_BX
-	gc.Thearch.REGCALLX2 = x86.REG_AX
-	gc.Thearch.REGRETURN = x86.REG_AX
-	gc.Thearch.REGMIN = x86.REG_AX
-	gc.Thearch.REGMAX = x86.REG_R15
-	gc.Thearch.FREGMIN = x86.REG_X0
-	gc.Thearch.FREGMAX = x86.REG_X15
 	gc.Thearch.MAXWIDTH = 1 << 50
 
 	gc.Thearch.Betypeinit = betypeinit

src/cmd/compile/internal/amd64/ggen.go

@@ -165,3 +165,14 @@ func zerorange(p *obj.Prog, frame int64, lo int64, hi int64, ax *uint32, x0 *uin
 
 	return p
 }
+
+func ginsnop() {
+	// This is actually not the x86 NOP anymore,
+	// but at the point where it gets used, AX is dead
+	// so it's okay if we lose the high bits.
+	p := gc.Prog(x86.AXCHGL)
+	p.From.Type = obj.TYPE_REG
+	p.From.Reg = x86.REG_AX
+	p.To.Type = obj.TYPE_REG
+	p.To.Reg = x86.REG_AX
+}

src/cmd/compile/internal/amd64/gsubr.go

-// Derived from Inferno utils/6c/txt.c
-// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6c/txt.c
-//
-//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
-//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
-//	Portions Copyright © 1997-1999 Vita Nuova Limited
-//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
-//	Portions Copyright © 2004,2006 Bruce Ellis
-//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
-//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
-//	Portions Copyright © 2009 The Go Authors. All rights reserved.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-
-package amd64
-
-import (
-	"cmd/compile/internal/gc"
-	"cmd/internal/obj"
-	"cmd/internal/obj/x86"
-)
-
-var resvd = []int{
-	x86.REG_DI, // for movstring
-	x86.REG_SI, // for movstring
-
-	x86.REG_AX, // for divide
-	x86.REG_CX, // for shift
-	x86.REG_DX, // for divide
-	x86.REG_SP, // for stack
-}
-
-func ginsnop() {
-	// This is actually not the x86 NOP anymore,
-	// but at the point where it gets used, AX is dead
-	// so it's okay if we lose the high bits.
-	p := gc.Prog(x86.AXCHGL)
-	p.From.Type = obj.TYPE_REG
-	p.From.Reg = x86.REG_AX
-	p.To.Type = obj.TYPE_REG
-	p.To.Reg = x86.REG_AX
-}

src/cmd/compile/internal/arm/galign.go

@@ -17,15 +17,7 @@ func Main() {
 	gc.Thearch.LinkArch = &arm.Linkarm
 	gc.Thearch.REGSP = arm.REGSP
 	gc.Thearch.REGCTXT = arm.REGCTXT
-	gc.Thearch.REGCALLX = arm.REG_R1
-	gc.Thearch.REGCALLX2 = arm.REG_R2
-	gc.Thearch.REGRETURN = arm.REG_R0
-	gc.Thearch.REGMIN = arm.REG_R0
-	gc.Thearch.REGMAX = arm.REGEXT
-	gc.Thearch.FREGMIN = arm.REG_F0
-	gc.Thearch.FREGMAX = arm.FREGEXT
 	gc.Thearch.MAXWIDTH = (1 << 32) - 1
-	gc.Thearch.ReservedRegs = resvd
 
 	gc.Thearch.Betypeinit = betypeinit
 	gc.Thearch.Defframe = defframe

src/cmd/compile/internal/arm/gsubr.go

-// Derived from Inferno utils/5c/txt.c
-// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/5c/txt.c
-//
-//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
-//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
-//	Portions Copyright © 1997-1999 Vita Nuova Limited
-//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
-//	Portions Copyright © 2004,2006 Bruce Ellis
-//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
-//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
-//	Portions Copyright © 2009 The Go Authors. All rights reserved.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-
-package arm
-
-import "cmd/internal/obj/arm"
-
-var resvd = []int{
-	arm.REG_R9,  // formerly reserved for m; might be okay to reuse now; not sure about NaCl
-	arm.REG_R10, // reserved for g
-}

src/cmd/compile/internal/arm64/galign.go

@@ -17,16 +17,7 @@ func Main() {
 	gc.Thearch.LinkArch = &arm64.Linkarm64
 	gc.Thearch.REGSP = arm64.REGSP
 	gc.Thearch.REGCTXT = arm64.REGCTXT
-	gc.Thearch.REGCALLX = arm64.REGRT1
-	gc.Thearch.REGCALLX2 = arm64.REGRT2
-	gc.Thearch.REGRETURN = arm64.REG_R0
-	gc.Thearch.REGMIN = arm64.REG_R0
-	gc.Thearch.REGMAX = arm64.REG_R31
-	gc.Thearch.REGZERO = arm64.REGZERO
-	gc.Thearch.FREGMIN = arm64.REG_F0
-	gc.Thearch.FREGMAX = arm64.REG_F31
 	gc.Thearch.MAXWIDTH = 1 << 50
-	gc.Thearch.ReservedRegs = resvd
 
 	gc.Thearch.Betypeinit = betypeinit
 	gc.Thearch.Defframe = defframe

src/cmd/compile/internal/arm64/gsubr.go

-// Derived from Inferno utils/6c/txt.c
-// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6c/txt.c
-//
-//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
-//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
-//	Portions Copyright © 1997-1999 Vita Nuova Limited
-//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
-//	Portions Copyright © 2004,2006 Bruce Ellis
-//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
-//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
-//	Portions Copyright © 2009 The Go Authors. All rights reserved.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-
-package arm64
-
-import "cmd/internal/obj/arm64"
-
-var resvd = []int{
-	arm64.REGTMP,
-	arm64.REGG,
-	arm64.REGRT1,
-	arm64.REGRT2,
-	arm64.REG_R31, // REGZERO and REGSP
-}

src/cmd/compile/internal/gc/go.go

@@ -357,16 +357,7 @@ type Arch struct {
 
 	REGSP    int
 	REGCTXT  int
-	REGCALLX     int // BX
-	REGCALLX2    int // AX
-	REGRETURN    int // AX
-	REGMIN       int
-	REGMAX       int
-	REGZERO      int // architectural zero register, if available
-	FREGMIN      int
-	FREGMAX      int
 	MAXWIDTH int64
-	ReservedRegs []int
 
 	Betypeinit func()
 	Defframe   func(*obj.Prog)

src/cmd/compile/internal/mips64/galign.go

@@ -21,15 +21,7 @@ func Main() {
 	}
 	gc.Thearch.REGSP = mips.REGSP
 	gc.Thearch.REGCTXT = mips.REGCTXT
-	gc.Thearch.REGCALLX = mips.REG_R1
-	gc.Thearch.REGCALLX2 = mips.REG_R2
-	gc.Thearch.REGRETURN = mips.REGRET
-	gc.Thearch.REGMIN = mips.REG_R0
-	gc.Thearch.REGMAX = mips.REG_R31
-	gc.Thearch.FREGMIN = mips.REG_F0
-	gc.Thearch.FREGMAX = mips.REG_F31
 	gc.Thearch.MAXWIDTH = 1 << 50
-	gc.Thearch.ReservedRegs = resvd
 
 	gc.Thearch.Betypeinit = betypeinit
 	gc.Thearch.Defframe = defframe

src/cmd/compile/internal/mips64/gsubr.go

-// Derived from Inferno utils/6c/txt.c
-// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6c/txt.c
-//
-//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
-//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
-//	Portions Copyright © 1997-1999 Vita Nuova Limited
-//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
-//	Portions Copyright © 2004,2006 Bruce Ellis
-//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
-//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
-//	Portions Copyright © 2009 The Go Authors. All rights reserved.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-
-package mips64
-
-import "cmd/internal/obj/mips"
-
-var resvd = []int{
-	mips.REGZERO,
-	mips.REGSP,   // reserved for SP
-	mips.REGSB,   // reserved for SB
-	mips.REGLINK, // reserved for link
-	mips.REGG,
-	mips.REGTMP,
-	mips.REG_R26, // kernel
-	mips.REG_R27, // kernel
-}

src/cmd/compile/internal/ppc64/galign.go

@@ -11,10 +11,6 @@ import (
 )
 
 func betypeinit() {
-	if gc.Ctxt.Flag_shared {
-		gc.Thearch.ReservedRegs = append(gc.Thearch.ReservedRegs, ppc64.REG_R2)
-		gc.Thearch.ReservedRegs = append(gc.Thearch.ReservedRegs, ppc64.REG_R12)
-	}
 }
 
 func Main() {
@@ -24,15 +20,7 @@ func Main() {
 	}
 	gc.Thearch.REGSP = ppc64.REGSP
 	gc.Thearch.REGCTXT = ppc64.REGCTXT
-	gc.Thearch.REGCALLX = ppc64.REG_R3
-	gc.Thearch.REGCALLX2 = ppc64.REG_R4
-	gc.Thearch.REGRETURN = ppc64.REG_R3
-	gc.Thearch.REGMIN = ppc64.REG_R0
-	gc.Thearch.REGMAX = ppc64.REG_R31
-	gc.Thearch.FREGMIN = ppc64.REG_F0
-	gc.Thearch.FREGMAX = ppc64.REG_F31
 	gc.Thearch.MAXWIDTH = 1 << 50
-	gc.Thearch.ReservedRegs = resvd
 
 	gc.Thearch.Betypeinit = betypeinit
 	gc.Thearch.Defframe = defframe

src/cmd/compile/internal/ppc64/gsubr.go

-// Derived from Inferno utils/6c/txt.c
-// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6c/txt.c
-//
-//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
-//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
-//	Portions Copyright © 1997-1999 Vita Nuova Limited
-//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
-//	Portions Copyright © 2004,2006 Bruce Ellis
-//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
-//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
-//	Portions Copyright © 2009 The Go Authors. All rights reserved.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-
-package ppc64
-
-import "cmd/internal/obj/ppc64"
-
-var resvd = []int{
-	ppc64.REGZERO,
-	ppc64.REGSP, // reserved for SP
-	// We need to preserve the C ABI TLS pointer because sigtramp
-	// may happen during C code and needs to access the g. C
-	// clobbers REGG, so if Go were to clobber REGTLS, sigtramp
-	// won't know which convention to use. By preserving REGTLS,
-	// we can just retrieve g from TLS when we aren't sure.
-	ppc64.REGTLS,
-
-	// TODO(austin): Consolidate REGTLS and REGG?
-	ppc64.REGG,
-	ppc64.REGTMP, // REGTMP
-}

src/cmd/compile/internal/s390x/galign.go

@@ -16,15 +16,7 @@ func Main() {
 	gc.Thearch.LinkArch = &s390x.Links390x
 	gc.Thearch.REGSP = s390x.REGSP
 	gc.Thearch.REGCTXT = s390x.REGCTXT
-	gc.Thearch.REGCALLX = s390x.REG_R3
-	gc.Thearch.REGCALLX2 = s390x.REG_R4
-	gc.Thearch.REGRETURN = s390x.REG_R3
-	gc.Thearch.REGMIN = s390x.REG_R0
-	gc.Thearch.REGMAX = s390x.REG_R15
-	gc.Thearch.FREGMIN = s390x.REG_F0
-	gc.Thearch.FREGMAX = s390x.REG_F15
 	gc.Thearch.MAXWIDTH = 1 << 50
-	gc.Thearch.ReservedRegs = resvd
 
 	gc.Thearch.Betypeinit = betypeinit
 	gc.Thearch.Defframe = defframe

src/cmd/compile/internal/s390x/gsubr.go

-// Derived from Inferno utils/6c/txt.c
-// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6c/txt.c
-//
-//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
-//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
-//	Portions Copyright © 1997-1999 Vita Nuova Limited
-//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
-//	Portions Copyright © 2004,2006 Bruce Ellis
-//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
-//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
-//	Portions Copyright © 2009 The Go Authors.  All rights reserved.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-
-package s390x
-
-import "cmd/internal/obj/s390x"
-
-var resvd = []int{
-	s390x.REGZERO, // R0
-	s390x.REGTMP,  // R10
-	s390x.REGTMP2, // R11
-	s390x.REGCTXT, // R12
-	s390x.REGG,    // R13
-	s390x.REG_LR,  // R14
-	s390x.REGSP,   // R15
-}

src/cmd/compile/internal/x86/galign.go

@@ -19,25 +19,15 @@ func Main() {
 	gc.Thearch.LinkArch = &x86.Link386
 	gc.Thearch.REGSP = x86.REGSP
 	gc.Thearch.REGCTXT = x86.REGCTXT
-	gc.Thearch.REGCALLX = x86.REG_BX
-	gc.Thearch.REGCALLX2 = x86.REG_AX
-	gc.Thearch.REGRETURN = x86.REG_AX
-	gc.Thearch.REGMIN = x86.REG_AX
-	gc.Thearch.REGMAX = x86.REG_DI
 	switch v := obj.GO386; v {
 	case "387":
-		gc.Thearch.FREGMIN = x86.REG_F0
-		gc.Thearch.FREGMAX = x86.REG_F7
 		gc.Thearch.Use387 = true
 	case "sse2":
-		gc.Thearch.FREGMIN = x86.REG_X0
-		gc.Thearch.FREGMAX = x86.REG_X7
 	default:
 		fmt.Fprintf(os.Stderr, "unsupported setting GO386=%s\n", v)
 		gc.Exit(1)
 	}
 	gc.Thearch.MAXWIDTH = (1 << 32) - 1
-	gc.Thearch.ReservedRegs = resvd
 
 	gc.Thearch.Betypeinit = betypeinit
 	gc.Thearch.Defframe = defframe

src/cmd/compile/internal/x86/ggen.go

@@ -83,3 +83,11 @@ func zerorange(p *obj.Prog, frame int64, lo int64, hi int64, ax *uint32) *obj.Pr
 
 	return p
 }
+
+func ginsnop() {
+	p := gc.Prog(x86.AXCHGL)
+	p.From.Type = obj.TYPE_REG
+	p.From.Reg = x86.REG_AX
+	p.To.Type = obj.TYPE_REG
+	p.To.Reg = x86.REG_AX
+}

src/cmd/compile/internal/x86/gsubr.go

-// Derived from Inferno utils/8c/txt.c
-// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/8c/txt.c
-//
-//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
-//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
-//	Portions Copyright © 1997-1999 Vita Nuova Limited
-//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
-//	Portions Copyright © 2004,2006 Bruce Ellis
-//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
-//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
-//	Portions Copyright © 2009 The Go Authors. All rights reserved.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-
-package x86
-
-import (
-	"cmd/compile/internal/gc"
-	"cmd/internal/obj"
-	"cmd/internal/obj/x86"
-)
-
-var resvd = []int{
-	//	REG_DI,	// for movstring
-	//	REG_SI,	// for movstring
-
-	x86.REG_AX, // for divide
-	x86.REG_CX, // for shift
-	x86.REG_DX, // for divide, context
-	x86.REG_SP, // for stack
-}
-
-func ginsnop() {
-	p := gc.Prog(x86.AXCHGL)
-	p.From.Type = obj.TYPE_REG
-	p.From.Reg = x86.REG_AX
-	p.To.Type = obj.TYPE_REG
-	p.To.Reg = x86.REG_AX
-}