diff --git a/src/cmd/asm/internal/asm/testdata/amd64enc_extra.s b/src/cmd/asm/internal/asm/testdata/amd64enc_extra.s
index d7afecc230..a7d9bdac54 100644
--- a/src/cmd/asm/internal/asm/testdata/amd64enc_extra.s
+++ b/src/cmd/asm/internal/asm/testdata/amd64enc_extra.s
@@ -1049,5 +1049,11 @@ TEXT asmtest(SB),DUPOK|NOSPLIT,$0
 	VADDPD Z2, Z9, Z21 // 62e1b54858ea
 	VADDPD Z21, Z2, Z9 // 6231ed4858cd
 	VADDPD Z9, Z21, Z2 // 62d1d54058d1
+
+	CLWB (BX) // 660fae33
+	CLDEMOTE (BX) // 0f1c03
+	TPAUSE BX // 660faef3
+	UMONITOR BX // f30faef3
+	UMWAIT BX // f20faef3
 	// End of tests.
 	RET
diff --git a/src/cmd/asm/internal/asm/testdata/amd64error.s b/src/cmd/asm/internal/asm/testdata/amd64error.s
index 93272e39d5..7e91fb4e97 100644
--- a/src/cmd/asm/internal/asm/testdata/amd64error.s
+++ b/src/cmd/asm/internal/asm/testdata/amd64error.s
@@ -132,4 +132,12 @@ TEXT errors(SB),$0
 	VADDPD.BCST X3, X2, K1, X1       // ERROR "illegal broadcast without memory argument"
 	VADDPD.BCST X3, X2, K1, X1       // ERROR "illegal broadcast without memory argument"
 	VADDPD.BCST X3, X2, K1, X1       // ERROR "illegal broadcast without memory argument"
+	// CLWB instuctions:
+	CLWB BX                          // ERROR "invalid instruction"
+	// CLDEMOTE instructions:
+	CLDEMOTE BX                      // ERROR "invalid instruction"
+	// WAITPKG instructions:
+	TPAUSE (BX)                      // ERROR "invalid instruction"
+	UMONITOR (BX)                    // ERROR "invalid instruction"
+	UMWAIT (BX)                      // ERROR "invalid instruction"
 	RET
diff --git a/src/cmd/internal/obj/x86/aenum.go b/src/cmd/internal/obj/x86/aenum.go
index 0377b39a41..2c035641f5 100644
--- a/src/cmd/internal/obj/x86/aenum.go
+++ b/src/cmd/internal/obj/x86/aenum.go
@@ -90,10 +90,12 @@ const (
 	ACLAC
 	ACLC
 	ACLD
+	ACLDEMOTE
 	ACLFLUSH
 	ACLFLUSHOPT
 	ACLI
 	ACLTS
+	ACLWB
 	ACMC
 	ACMOVLCC
 	ACMOVLCS
@@ -877,6 +879,7 @@ const (
 	ATESTL
 	ATESTQ
 	ATESTW
+	ATPAUSE
 	ATZCNTL
 	ATZCNTQ
 	ATZCNTW
@@ -884,10 +887,12 @@ const (
 	AUCOMISS
 	AUD1
 	AUD2
+	AUMWAIT
 	AUNPCKHPD
 	AUNPCKHPS
 	AUNPCKLPD
 	AUNPCKLPS
+	AUMONITOR
 	AV4FMADDPS
 	AV4FMADDSS
 	AV4FNMADDPS
diff --git a/src/cmd/internal/obj/x86/anames.go b/src/cmd/internal/obj/x86/anames.go
index a928f67bae..e6c00bdbe0 100644
--- a/src/cmd/internal/obj/x86/anames.go
+++ b/src/cmd/internal/obj/x86/anames.go
@@ -88,10 +88,12 @@ var Anames = []string{
 	"CLAC",
 	"CLC",
 	"CLD",
+	"CLDEMOTE",
 	"CLFLUSH",
 	"CLFLUSHOPT",
 	"CLI",
 	"CLTS",
+	"CLWB",
 	"CMC",
 	"CMOVLCC",
 	"CMOVLCS",
@@ -875,6 +877,7 @@ var Anames = []string{
 	"TESTL",
 	"TESTQ",
 	"TESTW",
+	"TPAUSE",
 	"TZCNTL",
 	"TZCNTQ",
 	"TZCNTW",
@@ -882,10 +885,12 @@ var Anames = []string{
 	"UCOMISS",
 	"UD1",
 	"UD2",
+	"UMWAIT",
 	"UNPCKHPD",
 	"UNPCKHPS",
 	"UNPCKLPD",
 	"UNPCKLPS",
+	"UMONITOR",
 	"V4FMADDPS",
 	"V4FMADDSS",
 	"V4FNMADDPS",
diff --git a/src/cmd/internal/obj/x86/asm6.go b/src/cmd/internal/obj/x86/asm6.go
index f5359493d0..618e88212c 100644
--- a/src/cmd/internal/obj/x86/asm6.go
+++ b/src/cmd/internal/obj/x86/asm6.go
@@ -983,10 +983,12 @@ var optab =
 	{ACLAC, ynone, Pm, opBytes{01, 0xca}},
 	{ACLC, ynone, Px, opBytes{0xf8}},
 	{ACLD, ynone, Px, opBytes{0xfc}},
+	{ACLDEMOTE, yclflush, Pm, opBytes{0x1c, 00}},
 	{ACLFLUSH, yclflush, Pm, opBytes{0xae, 07}},
 	{ACLFLUSHOPT, yclflush, Pq, opBytes{0xae, 07}},
 	{ACLI, ynone, Px, opBytes{0xfa}},
 	{ACLTS, ynone, Pm, opBytes{0x06}},
+	{ACLWB, yclflush, Pq, opBytes{0xae, 06}},
 	{ACMC, ynone, Px, opBytes{0xf5}},
 	{ACMOVLCC, yml_rl, Pm, opBytes{0x43}},
 	{ACMOVLCS, yml_rl, Pm, opBytes{0x42}},
@@ -1500,6 +1502,7 @@ var optab =
 	{ATESTL, ytestl, Px, opBytes{0xa9, 0xf7, 00, 0x85, 0x85}},
 	{ATESTQ, ytestl, Pw, opBytes{0xa9, 0xf7, 00, 0x85, 0x85}},
 	{ATESTW, ytestl, Pe, opBytes{0xa9, 0xf7, 00, 0x85, 0x85}},
+	{ATPAUSE, ywrfsbase, Pq, opBytes{0xae, 06}},
 	{obj.ATEXT, ytext, Px, opBytes{}},
 	{AUCOMISD, yxm, Pe, opBytes{0x2e}},
 	{AUCOMISS, yxm, Pm, opBytes{0x2e}},
@@ -1507,6 +1510,7 @@ var optab =
 	{AUNPCKHPS, yxm, Pm, opBytes{0x15}},
 	{AUNPCKLPD, yxm, Pe, opBytes{0x14}},
 	{AUNPCKLPS, yxm, Pm, opBytes{0x14}},
+	{AUMONITOR, ywrfsbase, Pf3, opBytes{0xae, 06}},
 	{AVERR, ydivl, Pm, opBytes{0x00, 04}},
 	{AVERW, ydivl, Pm, opBytes{0x00, 05}},
 	{AWAIT, ynone, Px, opBytes{0x9b}},
@@ -1691,11 +1695,11 @@ var optab =
 	{AMOVDDUP, yxm, Pf2, opBytes{0x12}},
 	{AMOVSHDUP, yxm, Pf3, opBytes{0x16}},
 	{AMOVSLDUP, yxm, Pf3, opBytes{0x12}},
-
 	{ARDTSCP, ynone, Pm, opBytes{0x01, 0xf9, 0}},
 	{ASTAC, ynone, Pm, opBytes{0x01, 0xcb, 0}},
 	{AUD1, ynone, Pm, opBytes{0xb9, 0}},
 	{AUD2, ynone, Pm, opBytes{0x0b, 0}},
+	{AUMWAIT, ywrfsbase, Pf2, opBytes{0xae, 06}},
 	{ASYSENTER, ynone, Px, opBytes{0x0f, 0x34, 0}},
 	{ASYSENTER64, ynone, Pw, opBytes{0x0f, 0x34, 0}},
 	{ASYSEXIT, ynone, Px, opBytes{0x0f, 0x35, 0}},
diff --git a/src/cmd/internal/obj/x86/obj6.go b/src/cmd/internal/obj/x86/obj6.go
index 4554d4a525..f28fa65e95 100644
--- a/src/cmd/internal/obj/x86/obj6.go
+++ b/src/cmd/internal/obj/x86/obj6.go
@@ -1136,8 +1136,10 @@ func stacksplit(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, newprog obj.ProgA
 var unaryDst = map[obj.As]bool{
 	ABSWAPL:     true,
 	ABSWAPQ:     true,
+	ACLDEMOTE:   true,
 	ACLFLUSH:    true,
 	ACLFLUSHOPT: true,
+	ACLWB:       true,
 	ACMPXCHG16B: true,
 	ACMPXCHG8B:  true,
 	ADECB:       true,