diff --git a/src/cmd/asm/internal/asm/endtoend_test.go b/src/cmd/asm/internal/asm/endtoend_test.go
index 5c7a024..0759b7d 100644
--- a/src/cmd/asm/internal/asm/endtoend_test.go
+++ b/src/cmd/asm/internal/asm/endtoend_test.go
@@ -390,7 +390,12 @@
 }
 
 func TestAMD64EndToEnd(t *testing.T) {
-	testEndToEnd(t, "amd64", "amd64")
+	defer func(old string) { objabi.GOAMD64 = old }(objabi.GOAMD64)
+	for _, goamd64 := range []string{"normaljumps", "alignedjumps"} {
+		t.Logf("GOAMD64=%s", goamd64)
+		objabi.GOAMD64 = goamd64
+		testEndToEnd(t, "amd64", "amd64")
+	}
 }
 
 func Test386Encoder(t *testing.T) {
diff --git a/src/cmd/dist/build.go b/src/cmd/dist/build.go
index 9e2b4f3..d22ee1d 100644
--- a/src/cmd/dist/build.go
+++ b/src/cmd/dist/build.go
@@ -31,6 +31,7 @@
 	goos             string
 	goarm            string
 	go386            string
+	goamd64          string
 	gomips           string
 	gomips64         string
 	goppc64          string
@@ -151,6 +152,12 @@
 	}
 	go386 = b
 
+	b = os.Getenv("GOAMD64")
+	if b == "" {
+		b = "alignedjumps"
+	}
+	goamd64 = b
+
 	b = os.Getenv("GOMIPS")
 	if b == "" {
 		b = "hardfloat"
@@ -223,6 +230,7 @@
 
 	// For tools being invoked but also for os.ExpandEnv.
 	os.Setenv("GO386", go386)
+	os.Setenv("GOAMD64", goamd64)
 	os.Setenv("GOARCH", goarch)
 	os.Setenv("GOARM", goarm)
 	os.Setenv("GOHOSTARCH", gohostarch)
@@ -1163,6 +1171,9 @@
 	if goarch == "386" {
 		xprintf(format, "GO386", go386)
 	}
+	if goarch == "amd64" {
+		xprintf(format, "GOAMD64", goamd64)
+	}
 	if goarch == "mips" || goarch == "mipsle" {
 		xprintf(format, "GOMIPS", gomips)
 	}
diff --git a/src/cmd/dist/buildruntime.go b/src/cmd/dist/buildruntime.go
index 2744951..f11933c 100644
--- a/src/cmd/dist/buildruntime.go
+++ b/src/cmd/dist/buildruntime.go
@@ -42,6 +42,7 @@
 //
 //	const defaultGOROOT = <goroot>
 //	const defaultGO386 = <go386>
+//	const defaultGOAMD64 = <goamd64>
 //	const defaultGOARM = <goarm>
 //	const defaultGOMIPS = <gomips>
 //	const defaultGOMIPS64 = <gomips64>
@@ -71,6 +72,7 @@
 	fmt.Fprintf(&buf, "import \"runtime\"\n")
 	fmt.Fprintln(&buf)
 	fmt.Fprintf(&buf, "const defaultGO386 = `%s`\n", go386)
+	fmt.Fprintf(&buf, "const defaultGOAMD64 = `%s`\n", goamd64)
 	fmt.Fprintf(&buf, "const defaultGOARM = `%s`\n", goarm)
 	fmt.Fprintf(&buf, "const defaultGOMIPS = `%s`\n", gomips)
 	fmt.Fprintf(&buf, "const defaultGOMIPS64 = `%s`\n", gomips64)
diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go
index 8fe4881..81b4687 100644
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@@ -1754,6 +1754,9 @@
 // 	GO386
 // 		For GOARCH=386, the floating point instruction set.
 // 		Valid values are 387, sse2.
+// 	GOAMD64
+// 		For GOARCH=amd64, jumps can be optionally be aligned such that they do not end on
+// 		or cross 32 byte boundaries.  Valid values are alignedjumps (default), normaljumps.
 // 	GOMIPS
 // 		For GOARCH=mips{,le}, whether to use floating point instructions.
 // 		Valid values are hardfloat (default), softfloat.
diff --git a/src/cmd/go/internal/cfg/cfg.go b/src/cmd/go/internal/cfg/cfg.go
index 7f8f8e9..21f55e8 100644
--- a/src/cmd/go/internal/cfg/cfg.go
+++ b/src/cmd/go/internal/cfg/cfg.go
@@ -241,6 +241,7 @@
 	// Used in envcmd.MkEnv and build ID computations.
 	GOARM    = envOr("GOARM", fmt.Sprint(objabi.GOARM))
 	GO386    = envOr("GO386", objabi.GO386)
+	GOAMD64  = envOr("GOAMD64", objabi.GOAMD64)
 	GOMIPS   = envOr("GOMIPS", objabi.GOMIPS)
 	GOMIPS64 = envOr("GOMIPS64", objabi.GOMIPS64)
 	GOPPC64  = envOr("GOPPC64", fmt.Sprintf("%s%d", "power", objabi.GOPPC64))
@@ -266,6 +267,8 @@
 		return "GOARM", GOARM
 	case "386":
 		return "GO386", GO386
+	case "amd64":
+		return "GOAMD64", GOAMD64
 	case "mips", "mipsle":
 		return "GOMIPS", GOMIPS
 	case "mips64", "mips64le":
diff --git a/src/cmd/go/internal/help/helpdoc.go b/src/cmd/go/internal/help/helpdoc.go
index 693de8f..9583b3f 100644
--- a/src/cmd/go/internal/help/helpdoc.go
+++ b/src/cmd/go/internal/help/helpdoc.go
@@ -582,6 +582,9 @@
 	GO386
 		For GOARCH=386, the floating point instruction set.
 		Valid values are 387, sse2.
+	GOAMD64
+		For GOARCH=amd64, jumps can be optionally be aligned such that they do not end on
+		or cross 32 byte boundaries.  Valid values are alignedjumps (default), normaljumps.
 	GOMIPS
 		For GOARCH=mips{,le}, whether to use floating point instructions.
 		Valid values are hardfloat (default), softfloat.
diff --git a/src/cmd/internal/obj/x86/asm6.go b/src/cmd/internal/obj/x86/asm6.go
index 5597aab..3eaed2a 100644
--- a/src/cmd/internal/obj/x86/asm6.go
+++ b/src/cmd/internal/obj/x86/asm6.go
@@ -1838,6 +1838,12 @@
 	}
 }
 
+func noppad(ctxt *obj.Link, s *obj.LSym, c int32, pad int32) int32 {
+	s.Grow(int64(c) + int64(pad))
+	fillnop(s.P[c:], int(pad))
+	return c + pad
+}
+
 func spadjop(ctxt *obj.Link, l, q obj.As) obj.As {
 	if ctxt.Arch.Family != sys.AMD64 || ctxt.Arch.PtrSize == 4 {
 		return l
@@ -1845,7 +1851,197 @@
 	return q
 }
 
+// If the environment variable GOAMD64=alignedjumps the assembler will ensure that
+// no standalone or macro-fused jump will straddle or end on a 32 byte boundary
+// by inserting NOPs before the jumps
+func isJump(p *obj.Prog) bool {
+	return p.Pcond != nil || p.As == obj.AJMP || p.As == obj.ACALL ||
+		p.As == obj.ARET || p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO
+}
+
+// lookForJCC returns the first real instruction starting from p, if that instruction is a conditional
+// jump. Otherwise, nil is returned.
+func lookForJCC(p *obj.Prog) *obj.Prog {
+	// Skip any PCDATA, FUNCDATA or NOP instructions
+	var q *obj.Prog
+	for q = p.Link; q != nil && (q.As == obj.APCDATA || q.As == obj.AFUNCDATA || q.As == obj.ANOP); q = q.Link {
+	}
+
+	if q == nil || q.Pcond == nil || p.As == obj.AJMP || p.As == obj.ACALL {
+		return nil
+	}
+
+	switch q.As {
+	case AJOS, AJOC, AJCS, AJCC, AJEQ, AJNE, AJLS, AJHI,
+		AJMI, AJPL, AJPS, AJPC, AJLT, AJGE, AJLE, AJGT:
+	default:
+		return nil
+	}
+
+	return q
+}
+
+// fusedJump determines whether p can be fused with a subsequent conditional jump instruction.
+// If it can, we return true followed by the total size of the fused jump. If it can't, we return false.
+// Macro fusion rules are derived from the Intel Optimization Manual (April 2019) section 3.4.2.2.
+func fusedJump(p *obj.Prog) (bool, uint8) {
+	var fusedSize uint8
+
+	// The first instruction in a macro fused pair may be preceeded by the LOCK prefix,
+	// or possibly an XACQUIRE/XRELEASE prefix followed by a LOCK prefix. If it is, we
+	// need to be careful to insert any padding before the locks rather than directly after them.
+
+	if p.As == AXRELEASE || p.As == AXACQUIRE {
+		fusedSize += p.Isize
+		for p = p.Link; p != nil && (p.As == obj.APCDATA || p.As == obj.AFUNCDATA); p = p.Link {
+		}
+		if p == nil {
+			return false, 0
+		}
+	}
+	if p.As == ALOCK {
+		fusedSize += p.Isize
+		for p = p.Link; p != nil && (p.As == obj.APCDATA || p.As == obj.AFUNCDATA); p = p.Link {
+		}
+		if p == nil {
+			return false, 0
+		}
+	}
+	cmp := p.As == ACMPB || p.As == ACMPL || p.As == ACMPQ || p.As == ACMPW
+
+	cmpAddSub := p.As == AADDB || p.As == AADDL || p.As == AADDW || p.As == AADDQ ||
+		p.As == ASUBB || p.As == ASUBL || p.As == ASUBW || p.As == ASUBQ || cmp
+
+	testAnd := p.As == ATESTB || p.As == ATESTL || p.As == ATESTQ || p.As == ATESTW ||
+		p.As == AANDB || p.As == AANDL || p.As == AANDQ || p.As == AANDW
+
+	incDec := p.As == AINCB || p.As == AINCL || p.As == AINCQ || p.As == AINCW ||
+		p.As == ADECB || p.As == ADECL || p.As == ADECQ || p.As == ADECW
+
+	if !cmpAddSub && !testAnd && !incDec {
+		return false, 0
+	}
+
+	if !incDec {
+		var argOne obj.AddrType
+		var argTwo obj.AddrType
+		if cmp {
+			argOne = p.From.Type
+			argTwo = p.To.Type
+		} else {
+			argOne = p.To.Type
+			argTwo = p.From.Type
+		}
+		if argOne == obj.TYPE_REG {
+			if argTwo != obj.TYPE_REG && argTwo != obj.TYPE_CONST && argTwo != obj.TYPE_MEM {
+				return false, 0
+			}
+		} else if argOne == obj.TYPE_MEM {
+			if argTwo != obj.TYPE_REG {
+				return false, 0
+			}
+		} else {
+			return false, 0
+		}
+	}
+
+	fusedSize += p.Isize
+	jmp := lookForJCC(p)
+	if jmp == nil {
+		return false, 0
+	}
+
+	fusedSize += jmp.Isize
+
+	if testAnd {
+		return true, fusedSize
+	}
+
+	if jmp.As == AJOC || jmp.As == AJOS || jmp.As == AJMI ||
+		jmp.As == AJPL || jmp.As == AJPS || jmp.As == AJPC {
+		return false, 0
+	}
+
+	if cmpAddSub {
+		return true, fusedSize
+	}
+
+	if jmp.As == AJCS || jmp.As == AJCC || jmp.As == AJHI || jmp.As == AJLS {
+		return false, 0
+	}
+
+	return true, fusedSize
+}
+
+type padJumpsCtx int32
+
+func makePjcCtx(ctxt *obj.Link) padJumpsCtx {
+	// Disable jump padding on 32 bit builds by settting
+	// padJumps to 0.
+	if ctxt.Arch.Family == sys.I386 {
+		return padJumpsCtx(0)
+	}
+
+	// Disable jump padding for hand written assembly code.
+	if ctxt.IsAsm {
+		return padJumpsCtx(0)
+	}
+
+	if objabi.GOAMD64 != "alignedjumps" {
+		return padJumpsCtx(0)
+
+	}
+
+	return padJumpsCtx(32)
+}
+
+// padJump detects whether the instruction being assembled is a standalone or a macro-fused
+// jump that needs to be padded. If it is, NOPs are inserted to ensure that the jump does
+// not cross or end on a 32 byte boundary.
+func (pjc padJumpsCtx) padJump(ctxt *obj.Link, s *obj.LSym, p *obj.Prog, c int32) int32 {
+	if pjc == 0 {
+		return c
+	}
+
+	var toPad int32
+	fj, fjSize := fusedJump(p)
+	mask := int32(pjc - 1)
+	if fj {
+		if (c&mask)+int32(fjSize) >= int32(pjc) {
+			toPad = int32(pjc) - (c & mask)
+		}
+	} else if isJump(p) {
+		if (c&mask)+int32(p.Isize) >= int32(pjc) {
+			toPad = int32(pjc) - (c & mask)
+		}
+	}
+	if toPad <= 0 {
+		return c
+	}
+
+	return noppad(ctxt, s, c, toPad)
+}
+
+// reAssemble is called if an instruction's size changes during assembly. If
+// it does and the instruction is a standalone or a macro-fused jump we need to
+// reassemble.
+func (pjc padJumpsCtx) reAssemble(p *obj.Prog) bool {
+	if pjc == 0 {
+		return false
+	}
+
+	fj, _ := fusedJump(p)
+	return fj || isJump(p)
+}
+
+type nopPad struct {
+	p *obj.Prog // Instruction before the pad
+	n int32     // Size of the pad
+}
+
 func span6(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
+	pjc := makePjcCtx(ctxt)
+
 	if s.P != nil {
 		return
 	}
@@ -1903,6 +2099,7 @@
 	var n int
 	var c int32
 	errors := ctxt.Errors
+	var nops []nopPad // Padding for a particular assembly (reuse slice storage if multiple assemblies)
 	for {
 		// This loop continues while there are reasons to re-assemble
 		// whole block, like the presence of long forward jumps.
@@ -1913,9 +2110,13 @@
 		s.R = s.R[:0]
 		s.P = s.P[:0]
 		c = 0
+		var pPrev *obj.Prog
+		nops = nops[:0]
 		for p := s.Func.Text; p != nil; p = p.Link {
+			c0 := c
+			c = pjc.padJump(ctxt, s, p, c)
 
-			if (p.Back&branchLoopHead != 0) && c&(loopAlign-1) != 0 {
+			if maxLoopPad > 0 && p.Back&branchLoopHead != 0 && c&(loopAlign-1) != 0 {
 				// pad with NOPs
 				v := -c & (loopAlign - 1)
 
@@ -1954,11 +2155,21 @@
 			m := ab.Len()
 			if int(p.Isize) != m {
 				p.Isize = uint8(m)
+				if pjc.reAssemble(p) {
+					// We need to re-assemble here to check for jumps and fused jumps
+					// that span or end on 32 byte boundaries.
+					reAssemble = true
+				}
 			}
 
 			s.Grow(p.Pc + int64(m))
 			copy(s.P[p.Pc:], ab.Bytes())
+			// If there was padding, remember it.
+			if pPrev != nil && !ctxt.IsAsm && c > c0 {
+				nops = append(nops, nopPad{p: pPrev, n: c - c0})
+			}
 			c += int32(m)
+			pPrev = p
 		}
 
 		n++
@@ -1973,6 +2184,12 @@
 			return
 		}
 	}
+	// splice padding nops into Progs
+	for _, n := range nops {
+		pp := n.p
+		np := &obj.Prog{Link: pp.Link, Ctxt: pp.Ctxt, As: obj.ANOP, Pos: pp.Pos.WithNotStmt(), Pc: pp.Pc + int64(pp.Isize), Isize: uint8(n.n)}
+		pp.Link = np
+	}
 
 	s.Size = int64(c)
 
diff --git a/src/cmd/internal/objabi/util.go b/src/cmd/internal/objabi/util.go
index 8d05a6b..72dd585 100644
--- a/src/cmd/internal/objabi/util.go
+++ b/src/cmd/internal/objabi/util.go
@@ -25,6 +25,7 @@
 	GOARCH   = envOr("GOARCH", defaultGOARCH)
 	GOOS     = envOr("GOOS", defaultGOOS)
 	GO386    = envOr("GO386", defaultGO386)
+	GOAMD64  = goamd64()
 	GOARM    = goarm()
 	GOMIPS   = gomips()
 	GOMIPS64 = gomips64()
@@ -39,6 +40,15 @@
 	MachoRelocOffset = 2048 // reserve enough space for ELF relocations
 )
 
+func goamd64() string {
+	switch v := envOr("GOAMD64", defaultGOAMD64); v {
+	case "normaljumps", "alignedjumps":
+		return v
+	}
+	log.Fatalf("Invalid GOAMD64 value. Must be normaljumps or alignedjumps.")
+	panic("unreachable")
+}
+
 func goarm() int {
 	switch v := envOr("GOARM", defaultGOARM); v {
 	case "5":
diff --git a/src/cmd/link/internal/amd64/obj.go b/src/cmd/link/internal/amd64/obj.go
index 645547c..1fa8cbb 100644
--- a/src/cmd/link/internal/amd64/obj.go
+++ b/src/cmd/link/internal/amd64/obj.go
@@ -39,8 +39,13 @@
 func Init() (*sys.Arch, ld.Arch) {
 	arch := sys.ArchAMD64
 
+	fa := funcAlign
+	if objabi.GOAMD64 == "alignedjumps" {
+		fa = 32
+	}
+
 	theArch := ld.Arch{
-		Funcalign:  funcAlign,
+		Funcalign:  fa,
 		Maxalign:   maxAlign,
 		Minalign:   minAlign,
 		Dwarfregsp: dwarfRegSP,
diff --git a/src/internal/cfg/cfg.go b/src/internal/cfg/cfg.go
index bdbe9df..e40b7b4 100644
--- a/src/internal/cfg/cfg.go
+++ b/src/internal/cfg/cfg.go
@@ -33,6 +33,7 @@
 	GCCGO
 	GO111MODULE
 	GO386
+	GOAMD64
 	GOARCH
 	GOARM
 	GOBIN