diff --git a/src/cmd/compile/internal/gc/builtin.go b/src/cmd/compile/internal/gc/builtin.go
index 9f8aa2697b..c1506f7874 100644
--- a/src/cmd/compile/internal/gc/builtin.go
+++ b/src/cmd/compile/internal/gc/builtin.go
@@ -49,7 +49,19 @@ var runtimeDecls = [...]struct {
 	{"slicestringcopy", funcTag, 51},
 	{"convI2I", funcTag, 52},
 	{"convT2E", funcTag, 53},
+	{"convT2E16", funcTag, 53},
+	{"convT2E32", funcTag, 53},
+	{"convT2E64", funcTag, 53},
+	{"convT2Estring", funcTag, 53},
+	{"convT2Eslice", funcTag, 53},
+	{"convT2Enoptr", funcTag, 53},
 	{"convT2I", funcTag, 53},
+	{"convT2I16", funcTag, 53},
+	{"convT2I32", funcTag, 53},
+	{"convT2I64", funcTag, 53},
+	{"convT2Istring", funcTag, 53},
+	{"convT2Islice", funcTag, 53},
+	{"convT2Inoptr", funcTag, 53},
 	{"assertE2I", funcTag, 52},
 	{"assertE2I2", funcTag, 54},
 	{"assertI2I", funcTag, 52},
diff --git a/src/cmd/compile/internal/gc/builtin/runtime.go b/src/cmd/compile/internal/gc/builtin/runtime.go
index fc55104ef8..2bc974387a 100644
--- a/src/cmd/compile/internal/gc/builtin/runtime.go
+++ b/src/cmd/compile/internal/gc/builtin/runtime.go
@@ -61,8 +61,22 @@ func slicestringcopy(to any, fr any) int
 
 // interface conversions
 func convI2I(typ *byte, elem any) (ret any)
+
 func convT2E(typ *byte, elem *any) (ret any)
+func convT2E16(typ *byte, elem *any) (ret any)
+func convT2E32(typ *byte, elem *any) (ret any)
+func convT2E64(typ *byte, elem *any) (ret any)
+func convT2Estring(typ *byte, elem *any) (ret any)
+func convT2Eslice(typ *byte, elem *any) (ret any)
+func convT2Enoptr(typ *byte, elem *any) (ret any)
+
 func convT2I(tab *byte, elem *any) (ret any)
+func convT2I16(tab *byte, elem *any) (ret any)
+func convT2I32(tab *byte, elem *any) (ret any)
+func convT2I64(tab *byte, elem *any) (ret any)
+func convT2Istring(tab *byte, elem *any) (ret any)
+func convT2Islice(tab *byte, elem *any) (ret any)
+func convT2Inoptr(tab *byte, elem *any) (ret any)
 
 // interface type assertions  x.(T)
 func assertE2I(typ *byte, iface any) (ret any)
diff --git a/src/cmd/compile/internal/gc/walk.go b/src/cmd/compile/internal/gc/walk.go
index 072c0ac69c..96f66148a5 100644
--- a/src/cmd/compile/internal/gc/walk.go
+++ b/src/cmd/compile/internal/gc/walk.go
@@ -417,8 +417,36 @@ func convFuncName(from, to *Type) string {
 	case 'T':
 		switch tkind {
 		case 'E':
+			switch {
+			case from.Size() == 2 && from.Align == 2:
+				return "convT2E16"
+			case from.Size() == 4 && from.Align == 4 && !haspointers(from):
+				return "convT2E32"
+			case from.Size() == 8 && from.Align == Types[TUINT64].Align && !haspointers(from):
+				return "convT2E64"
+			case from.IsString():
+				return "convT2Estring"
+			case from.IsSlice():
+				return "convT2Eslice"
+			case !haspointers(from):
+				return "convT2Enoptr"
+			}
 			return "convT2E"
 		case 'I':
+			switch {
+			case from.Size() == 2 && from.Align == 2:
+				return "convT2I16"
+			case from.Size() == 4 && from.Align == 4 && !haspointers(from):
+				return "convT2I32"
+			case from.Size() == 8 && from.Align == Types[TUINT64].Align && !haspointers(from):
+				return "convT2I64"
+			case from.IsString():
+				return "convT2Istring"
+			case from.IsSlice():
+				return "convT2Islice"
+			case !haspointers(from):
+				return "convT2Inoptr"
+			}
 			return "convT2I"
 		}
 	}
diff --git a/src/runtime/iface.go b/src/runtime/iface.go
index f043724a56..58ed61e3aa 100644
--- a/src/runtime/iface.go
+++ b/src/runtime/iface.go
@@ -205,19 +205,124 @@ func convT2E(t *_type, elem unsafe.Pointer) (e eface) {
 	if msanenabled {
 		msanread(elem, t.size)
 	}
-	if isDirectIface(t) {
-		// This case is implemented directly by the compiler.
-		throw("direct convT2E")
-	}
-	x := newobject(t)
-	// TODO: We allocate a zeroed object only to overwrite it with
-	// actual data. Figure out how to avoid zeroing. Also below in convT2I.
+	x := mallocgc(t.size, t, true)
+	// TODO: We allocate a zeroed object only to overwrite it with actual data.
+	// Figure out how to avoid zeroing. Also below in convT2Eslice, convT2I, convT2Islice.
 	typedmemmove(t, x, elem)
 	e._type = t
 	e.data = x
 	return
 }
 
+func convT2E16(t *_type, elem unsafe.Pointer) (e eface) {
+	if raceenabled {
+		raceReadObjectPC(t, elem, getcallerpc(unsafe.Pointer(&t)), funcPC(convT2E16))
+	}
+	if msanenabled {
+		msanread(elem, t.size)
+	}
+	var x unsafe.Pointer
+	if *(*uint16)(elem) == 0 {
+		x = unsafe.Pointer(&zeroVal[0])
+	} else {
+		x = mallocgc(2, t, false)
+		*(*uint16)(x) = *(*uint16)(elem)
+	}
+	e._type = t
+	e.data = x
+	return
+}
+
+func convT2E32(t *_type, elem unsafe.Pointer) (e eface) {
+	if raceenabled {
+		raceReadObjectPC(t, elem, getcallerpc(unsafe.Pointer(&t)), funcPC(convT2E32))
+	}
+	if msanenabled {
+		msanread(elem, t.size)
+	}
+	var x unsafe.Pointer
+	if *(*uint32)(elem) == 0 {
+		x = unsafe.Pointer(&zeroVal[0])
+	} else {
+		x = mallocgc(4, t, false)
+		*(*uint32)(x) = *(*uint32)(elem)
+	}
+	e._type = t
+	e.data = x
+	return
+}
+
+func convT2E64(t *_type, elem unsafe.Pointer) (e eface) {
+	if raceenabled {
+		raceReadObjectPC(t, elem, getcallerpc(unsafe.Pointer(&t)), funcPC(convT2E64))
+	}
+	if msanenabled {
+		msanread(elem, t.size)
+	}
+	var x unsafe.Pointer
+	if *(*uint64)(elem) == 0 {
+		x = unsafe.Pointer(&zeroVal[0])
+	} else {
+		x = mallocgc(8, t, false)
+		*(*uint64)(x) = *(*uint64)(elem)
+	}
+	e._type = t
+	e.data = x
+	return
+}
+
+func convT2Estring(t *_type, elem unsafe.Pointer) (e eface) {
+	if raceenabled {
+		raceReadObjectPC(t, elem, getcallerpc(unsafe.Pointer(&t)), funcPC(convT2Estring))
+	}
+	if msanenabled {
+		msanread(elem, t.size)
+	}
+	var x unsafe.Pointer
+	if *(*string)(elem) == "" {
+		x = unsafe.Pointer(&zeroVal[0])
+	} else {
+		x = mallocgc(t.size, t, true)
+		*(*string)(x) = *(*string)(elem)
+	}
+	e._type = t
+	e.data = x
+	return
+}
+
+func convT2Eslice(t *_type, elem unsafe.Pointer) (e eface) {
+	if raceenabled {
+		raceReadObjectPC(t, elem, getcallerpc(unsafe.Pointer(&t)), funcPC(convT2Eslice))
+	}
+	if msanenabled {
+		msanread(elem, t.size)
+	}
+	var x unsafe.Pointer
+	if v := *(*slice)(elem); uintptr(v.array) == 0 {
+		x = unsafe.Pointer(&zeroVal[0])
+	} else {
+		x = mallocgc(t.size, t, true)
+		*(*slice)(x) = *(*slice)(elem)
+	}
+	e._type = t
+	e.data = x
+	return
+}
+
+func convT2Enoptr(t *_type, elem unsafe.Pointer) (e eface) {
+	if raceenabled {
+		raceReadObjectPC(t, elem, getcallerpc(unsafe.Pointer(&t)), funcPC(convT2Enoptr))
+	}
+	if msanenabled {
+		msanread(elem, t.size)
+	}
+	x := mallocgc(t.size, t, false)
+	memmove(x, elem, t.size)
+	e._type = t
+	e.data = x
+	return
+}
+
 func convT2I(tab *itab, elem unsafe.Pointer) (i iface) {
 	t := tab._type
 	if raceenabled {
@@ -226,17 +331,128 @@ func convT2I(tab *itab, elem unsafe.Pointer) (i iface) {
 	if msanenabled {
 		msanread(elem, t.size)
 	}
-	if isDirectIface(t) {
-		// This case is implemented directly by the compiler.
-		throw("direct convT2I")
-	}
-	x := newobject(t)
+	x := mallocgc(t.size, t, true)
 	typedmemmove(t, x, elem)
 	i.tab = tab
 	i.data = x
 	return
 }
 
+func convT2I16(tab *itab, elem unsafe.Pointer) (i iface) {
+	t := tab._type
+	if raceenabled {
+		raceReadObjectPC(t, elem, getcallerpc(unsafe.Pointer(&tab)), funcPC(convT2I16))
+	}
+	if msanenabled {
+		msanread(elem, t.size)
+	}
+	var x unsafe.Pointer
+	if *(*uint16)(elem) == 0 {
+		x = unsafe.Pointer(&zeroVal[0])
+	} else {
+		x = mallocgc(2, t, false)
+		*(*uint16)(x) = *(*uint16)(elem)
+	}
+	i.tab = tab
+	i.data = x
+	return
+}
+
+func convT2I32(tab *itab, elem unsafe.Pointer) (i iface) {
+	t := tab._type
+	if raceenabled {
+		raceReadObjectPC(t, elem, getcallerpc(unsafe.Pointer(&tab)), funcPC(convT2I32))
+	}
+	if msanenabled {
+		msanread(elem, t.size)
+	}
+	var x unsafe.Pointer
+	if *(*uint32)(elem) == 0 {
+		x = unsafe.Pointer(&zeroVal[0])
+	} else {
+		x = mallocgc(4, t, false)
+		*(*uint32)(x) = *(*uint32)(elem)
+	}
+	i.tab = tab
+	i.data = x
+	return
+}
+
+func convT2I64(tab *itab, elem unsafe.Pointer) (i iface) {
+	t := tab._type
+	if raceenabled {
+		raceReadObjectPC(t, elem, getcallerpc(unsafe.Pointer(&tab)), funcPC(convT2I64))
+	}
+	if msanenabled {
+		msanread(elem, t.size)
+	}
+	var x unsafe.Pointer
+	if *(*uint64)(elem) == 0 {
+		x = unsafe.Pointer(&zeroVal[0])
+	} else {
+		x = mallocgc(8, t, false)
+		*(*uint64)(x) = *(*uint64)(elem)
+	}
+	i.tab = tab
+	i.data = x
+	return
+}
+
+func convT2Istring(tab *itab, elem unsafe.Pointer) (i iface) {
+	t := tab._type
+	if raceenabled {
+		raceReadObjectPC(t, elem, getcallerpc(unsafe.Pointer(&tab)), funcPC(convT2Istring))
+	}
+	if msanenabled {
+		msanread(elem, t.size)
+	}
+	var x unsafe.Pointer
+	if *(*string)(elem) == "" {
+		x = unsafe.Pointer(&zeroVal[0])
+	} else {
+		x = mallocgc(t.size, t, true)
+		*(*string)(x) = *(*string)(elem)
+	}
+	i.tab = tab
+	i.data = x
+	return
+}
+
+func convT2Islice(tab *itab, elem unsafe.Pointer) (i iface) {
+	t := tab._type
+	if raceenabled {
+		raceReadObjectPC(t, elem, getcallerpc(unsafe.Pointer(&tab)), funcPC(convT2Islice))
+	}
+	if msanenabled {
+		msanread(elem, t.size)
+	}
+	var x unsafe.Pointer
+	if v := *(*slice)(elem); uintptr(v.array) == 0 {
+		x = unsafe.Pointer(&zeroVal[0])
+	} else {
+		x = mallocgc(t.size, t, true)
+		*(*slice)(x) = *(*slice)(elem)
+	}
+	i.tab = tab
+	i.data = x
+	return
+}
+
+func convT2Inoptr(tab *itab, elem unsafe.Pointer) (i iface) {
+	t := tab._type
+	if raceenabled {
+		raceReadObjectPC(t, elem, getcallerpc(unsafe.Pointer(&tab)), funcPC(convT2Inoptr))
+	}
+	if msanenabled {
+		msanread(elem, t.size)
+	}
+	x := mallocgc(t.size, t, false)
+	memmove(x, elem, t.size)
+	i.tab = tab
+	i.data = x
+	return
+}
+
 func convI2I(inter *interfacetype, i iface) (r iface) {
 	tab := i.tab
 	if tab == nil {
diff --git a/src/runtime/iface_test.go b/src/runtime/iface_test.go
index 7f27baa61f..6d8f8614d9 100644
--- a/src/runtime/iface_test.go
+++ b/src/runtime/iface_test.go
@@ -29,6 +29,20 @@ func (TM) Method2() {}
 func (TL) Method1() {}
 func (TL) Method2() {}
 
+type T8 uint8
+type T16 uint16
+type T32 uint32
+type T64 uint64
+type Tstr string
+type Tslice []byte
+
+func (T8) Method1()     {}
+func (T16) Method1()    {}
+func (T32) Method1()    {}
+func (T64) Method1()    {}
+func (Tstr) Method1()   {}
+func (Tslice) Method1() {}
+
 var (
 	e  interface{}
 	e_ interface{}
@@ -261,3 +275,129 @@ func TestNonEscapingConvT2I(t *testing.T) {
 		t.Fatalf("want 0 allocs, got %v", n)
 	}
 }
+
+func TestZeroConvT2x(t *testing.T) {
+	tests := []struct {
+		name string
+		fn   func()
+	}{
+		{name: "E8", fn: func() { e = eight8 }},  // any byte-sized value does not allocate
+		{name: "E16", fn: func() { e = zero16 }}, // zero values do not allocate
+		{name: "E32", fn: func() { e = zero32 }},
+		{name: "E64", fn: func() { e = zero64 }},
+		{name: "Estr", fn: func() { e = zerostr }},
+		{name: "Eslice", fn: func() { e = zeroslice }},
+		{name: "Econstflt", fn: func() { e = 99.0 }}, // constants do not allocate
+		{name: "Econststr", fn: func() { e = "change" }},
+		{name: "I8", fn: func() { i1 = eight8I }},
+		{name: "I16", fn: func() { i1 = zero16I }},
+		{name: "I32", fn: func() { i1 = zero32I }},
+		{name: "I64", fn: func() { i1 = zero64I }},
+		{name: "Istr", fn: func() { i1 = zerostrI }},
+		{name: "Islice", fn: func() { i1 = zerosliceI }},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			n := testing.AllocsPerRun(1000, test.fn)
+			if n != 0 {
+				t.Errorf("want zero allocs, got %v", n)
+			}
+		})
+	}
+}
+
+var (
+	eight8  uint8 = 8
+	eight8I T8    = 8
+
+	zero16  uint16 = 0
+	zero16I T16    = 0
+	one16   uint16 = 1
+
+	zero32  uint32 = 0
+	zero32I T32    = 0
+	one32   uint32 = 1
+
+	zero64  uint64 = 0
+	zero64I T64    = 0
+	one64   uint64 = 1
+
+	zerostr  string = ""
+	zerostrI Tstr   = ""
+	nzstr    string = "abc"
+
+	zeroslice  []byte = nil
+	zerosliceI Tslice = nil
+	nzslice    []byte = []byte("abc")
+
+	zerobig [512]byte
+	nzbig   [512]byte = [512]byte{511: 1}
+)
+
+func BenchmarkConvT2Ezero(b *testing.B) {
+	b.Run("zero", func(b *testing.B) {
+		b.Run("16", func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				e = zero16
+			}
+		})
+		b.Run("32", func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				e = zero32
+			}
+		})
+		b.Run("64", func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				e = zero64
+			}
+		})
+		b.Run("str", func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				e = zerostr
+			}
+		})
+		b.Run("slice", func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				e = zeroslice
+			}
+		})
+		b.Run("big", func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				e = zerobig
+			}
+		})
+	})
+	b.Run("nonzero", func(b *testing.B) {
+		b.Run("16", func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				e = one16
+			}
+		})
+		b.Run("32", func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				e = one32
+			}
+		})
+		b.Run("64", func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				e = one64
+			}
+		})
+		b.Run("str", func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				e = nzstr
+			}
+		})
+		b.Run("slice", func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				e = nzslice
+			}
+		})
+		b.Run("big", func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				e = nzbig
+			}
+		})
+	})
+}
diff --git a/test/live.go b/test/live.go
index 0466956254..708786339d 100644
--- a/test/live.go
+++ b/test/live.go
@@ -141,7 +141,7 @@ var i9 interface{}
 func f9() bool {
 	g8()
 	x := i9
-	y := interface{}(str()) // ERROR "live at call to convT2E: .autotmp_[0-9]+ x.data x.type$" "live at call to str: x.data x.type$"
+	y := interface{}(str()) // ERROR "live at call to convT2Estring: .autotmp_[0-9]+ x.data x.type$" "live at call to str: x.data x.type$"
 	i9 = y                  // make y escape so the line above has to call convT2E
 	return x != y
 }
@@ -494,13 +494,13 @@ func f30(b bool) {
 
 func f31(b1, b2, b3 bool) {
 	if b1 {
-		g31(str()) // ERROR "live at call to convT2E: .autotmp_[0-9]+$" "live at call to g31: .autotmp_[0-9]+$"
+		g31(str()) // ERROR "live at call to convT2Estring: .autotmp_[0-9]+$" "live at call to g31: .autotmp_[0-9]+$"
 	}
 	if b2 {
-		h31(str()) // ERROR "live at call to convT2E: .autotmp_[0-9]+ .autotmp_[0-9]+$" "live at call to h31: .autotmp_[0-9]+$" "live at call to newobject: .autotmp_[0-9]+$"
+		h31(str()) // ERROR "live at call to convT2Estring: .autotmp_[0-9]+ .autotmp_[0-9]+$" "live at call to h31: .autotmp_[0-9]+$" "live at call to newobject: .autotmp_[0-9]+$"
 	}
 	if b3 {
-		panic(str()) // ERROR "live at call to convT2E: .autotmp_[0-9]+$" "live at call to gopanic: .autotmp_[0-9]+$"
+		panic(str()) // ERROR "live at call to convT2Estring: .autotmp_[0-9]+$" "live at call to gopanic: .autotmp_[0-9]+$"
 	}
 	print(b3)
 }