[dev.typeparams] cmd/compile: simplify interface conversions

Simplify the implementation of interface conversions in the compiler.
Don't pass fields that aren't needed (the data word, usually) to the runtime.

For generics, we need to put a dynamic type in an interface. The new
dataWord function is exactly what we need (the type word will come
from a dictionary).

Change-Id: Iade5de5c174854b65ad248f35c7893c603f7be3d
Reviewed-on: https://go-review.googlesource.com/c/go/+/340029
Trust: Keith Randall <khr@golang.org>
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>

10 files changed, 395 insertions, 462 deletions

diff --git a/src/cmd/compile/internal/typecheck/builtin.go b/src/cmd/compile/internal/typecheck/builtin.go
index 833b17b414..3f177d9173 100644
--- a/src/cmd/compile/internal/typecheck/builtin.go
+++ b/src/cmd/compile/internal/typecheck/builtin.go
@@ -71,137 +71,135 @@ var runtimeDecls = [...]struct {
 	{"slicecopy", funcTag, 54},
 	{"decoderune", funcTag, 55},
 	{"countrunes", funcTag, 56},
-	{"convI2I", funcTag, 57},
-	{"convT16", funcTag, 59},
-	{"convT32", funcTag, 61},
-	{"convT64", funcTag, 62},
-	{"convTstring", funcTag, 63},
-	{"convTslice", funcTag, 66},
-	{"convT2E", funcTag, 67},
-	{"convT2Enoptr", funcTag, 67},
-	{"convT2I", funcTag, 67},
-	{"convT2Inoptr", funcTag, 67},
-	{"assertE2I", funcTag, 68},
-	{"assertE2I2", funcTag, 57},
-	{"assertI2I", funcTag, 68},
-	{"assertI2I2", funcTag, 57},
-	{"panicdottypeE", funcTag, 69},
-	{"panicdottypeI", funcTag, 69},
-	{"panicnildottype", funcTag, 70},
-	{"ifaceeq", funcTag, 72},
-	{"efaceeq", funcTag, 72},
-	{"fastrand", funcTag, 73},
-	{"makemap64", funcTag, 75},
-	{"makemap", funcTag, 76},
-	{"makemap_small", funcTag, 77},
-	{"mapaccess1", funcTag, 78},
-	{"mapaccess1_fast32", funcTag, 79},
-	{"mapaccess1_fast64", funcTag, 80},
-	{"mapaccess1_faststr", funcTag, 81},
-	{"mapaccess1_fat", funcTag, 82},
-	{"mapaccess2", funcTag, 83},
-	{"mapaccess2_fast32", funcTag, 84},
-	{"mapaccess2_fast64", funcTag, 85},
-	{"mapaccess2_faststr", funcTag, 86},
-	{"mapaccess2_fat", funcTag, 87},
-	{"mapassign", funcTag, 78},
-	{"mapassign_fast32", funcTag, 79},
-	{"mapassign_fast32ptr", funcTag, 88},
-	{"mapassign_fast64", funcTag, 80},
-	{"mapassign_fast64ptr", funcTag, 88},
-	{"mapassign_faststr", funcTag, 81},
-	{"mapiterinit", funcTag, 89},
-	{"mapdelete", funcTag, 89},
-	{"mapdelete_fast32", funcTag, 90},
-	{"mapdelete_fast64", funcTag, 91},
-	{"mapdelete_faststr", funcTag, 92},
-	{"mapiternext", funcTag, 93},
-	{"mapclear", funcTag, 94},
-	{"makechan64", funcTag, 96},
-	{"makechan", funcTag, 97},
-	{"chanrecv1", funcTag, 99},
-	{"chanrecv2", funcTag, 100},
-	{"chansend1", funcTag, 102},
+	{"convI2I", funcTag, 58},
+	{"convT", funcTag, 59},
+	{"convTnoptr", funcTag, 59},
+	{"convT16", funcTag, 61},
+	{"convT32", funcTag, 63},
+	{"convT64", funcTag, 64},
+	{"convTstring", funcTag, 65},
+	{"convTslice", funcTag, 68},
+	{"assertE2I", funcTag, 69},
+	{"assertE2I2", funcTag, 70},
+	{"assertI2I", funcTag, 69},
+	{"assertI2I2", funcTag, 70},
+	{"panicdottypeE", funcTag, 71},
+	{"panicdottypeI", funcTag, 71},
+	{"panicnildottype", funcTag, 72},
+	{"ifaceeq", funcTag, 73},
+	{"efaceeq", funcTag, 73},
+	{"fastrand", funcTag, 74},
+	{"makemap64", funcTag, 76},
+	{"makemap", funcTag, 77},
+	{"makemap_small", funcTag, 78},
+	{"mapaccess1", funcTag, 79},
+	{"mapaccess1_fast32", funcTag, 80},
+	{"mapaccess1_fast64", funcTag, 81},
+	{"mapaccess1_faststr", funcTag, 82},
+	{"mapaccess1_fat", funcTag, 83},
+	{"mapaccess2", funcTag, 84},
+	{"mapaccess2_fast32", funcTag, 85},
+	{"mapaccess2_fast64", funcTag, 86},
+	{"mapaccess2_faststr", funcTag, 87},
+	{"mapaccess2_fat", funcTag, 88},
+	{"mapassign", funcTag, 79},
+	{"mapassign_fast32", funcTag, 80},
+	{"mapassign_fast32ptr", funcTag, 89},
+	{"mapassign_fast64", funcTag, 81},
+	{"mapassign_fast64ptr", funcTag, 89},
+	{"mapassign_faststr", funcTag, 82},
+	{"mapiterinit", funcTag, 90},
+	{"mapdelete", funcTag, 90},
+	{"mapdelete_fast32", funcTag, 91},
+	{"mapdelete_fast64", funcTag, 92},
+	{"mapdelete_faststr", funcTag, 93},
+	{"mapiternext", funcTag, 94},
+	{"mapclear", funcTag, 95},
+	{"makechan64", funcTag, 97},
+	{"makechan", funcTag, 98},
+	{"chanrecv1", funcTag, 100},
+	{"chanrecv2", funcTag, 101},
+	{"chansend1", funcTag, 103},
 	{"closechan", funcTag, 30},
-	{"writeBarrier", varTag, 104},
-	{"typedmemmove", funcTag, 105},
-	{"typedmemclr", funcTag, 106},
-	{"typedslicecopy", funcTag, 107},
-	{"selectnbsend", funcTag, 108},
-	{"selectnbrecv", funcTag, 109},
-	{"selectsetpc", funcTag, 110},
-	{"selectgo", funcTag, 111},
+	{"writeBarrier", varTag, 105},
+	{"typedmemmove", funcTag, 106},
+	{"typedmemclr", funcTag, 107},
+	{"typedslicecopy", funcTag, 108},
+	{"selectnbsend", funcTag, 109},
+	{"selectnbrecv", funcTag, 110},
+	{"selectsetpc", funcTag, 111},
+	{"selectgo", funcTag, 112},
 	{"block", funcTag, 9},
-	{"makeslice", funcTag, 112},
-	{"makeslice64", funcTag, 113},
-	{"makeslicecopy", funcTag, 114},
-	{"growslice", funcTag, 116},
-	{"unsafeslice", funcTag, 117},
-	{"unsafeslice64", funcTag, 118},
-	{"unsafeslicecheckptr", funcTag, 118},
-	{"memmove", funcTag, 119},
-	{"memclrNoHeapPointers", funcTag, 120},
-	{"memclrHasPointers", funcTag, 120},
-	{"memequal", funcTag, 121},
-	{"memequal0", funcTag, 122},
-	{"memequal8", funcTag, 122},
-	{"memequal16", funcTag, 122},
-	{"memequal32", funcTag, 122},
-	{"memequal64", funcTag, 122},
-	{"memequal128", funcTag, 122},
-	{"f32equal", funcTag, 123},
-	{"f64equal", funcTag, 123},
-	{"c64equal", funcTag, 123},
-	{"c128equal", funcTag, 123},
-	{"strequal", funcTag, 123},
-	{"interequal", funcTag, 123},
-	{"nilinterequal", funcTag, 123},
-	{"memhash", funcTag, 124},
-	{"memhash0", funcTag, 125},
-	{"memhash8", funcTag, 125},
-	{"memhash16", funcTag, 125},
-	{"memhash32", funcTag, 125},
-	{"memhash64", funcTag, 125},
-	{"memhash128", funcTag, 125},
-	{"f32hash", funcTag, 125},
-	{"f64hash", funcTag, 125},
-	{"c64hash", funcTag, 125},
-	{"c128hash", funcTag, 125},
-	{"strhash", funcTag, 125},
-	{"interhash", funcTag, 125},
-	{"nilinterhash", funcTag, 125},
-	{"int64div", funcTag, 126},
-	{"uint64div", funcTag, 127},
-	{"int64mod", funcTag, 126},
-	{"uint64mod", funcTag, 127},
-	{"float64toint64", funcTag, 128},
-	{"float64touint64", funcTag, 129},
-	{"float64touint32", funcTag, 130},
-	{"int64tofloat64", funcTag, 131},
-	{"uint64tofloat64", funcTag, 132},
-	{"uint32tofloat64", funcTag, 133},
-	{"complex128div", funcTag, 134},
-	{"getcallerpc", funcTag, 135},
-	{"getcallersp", funcTag, 135},
+	{"makeslice", funcTag, 113},
+	{"makeslice64", funcTag, 114},
+	{"makeslicecopy", funcTag, 115},
+	{"growslice", funcTag, 117},
+	{"unsafeslice", funcTag, 118},
+	{"unsafeslice64", funcTag, 119},
+	{"unsafeslicecheckptr", funcTag, 119},
+	{"memmove", funcTag, 120},
+	{"memclrNoHeapPointers", funcTag, 121},
+	{"memclrHasPointers", funcTag, 121},
+	{"memequal", funcTag, 122},
+	{"memequal0", funcTag, 123},
+	{"memequal8", funcTag, 123},
+	{"memequal16", funcTag, 123},
+	{"memequal32", funcTag, 123},
+	{"memequal64", funcTag, 123},
+	{"memequal128", funcTag, 123},
+	{"f32equal", funcTag, 124},
+	{"f64equal", funcTag, 124},
+	{"c64equal", funcTag, 124},
+	{"c128equal", funcTag, 124},
+	{"strequal", funcTag, 124},
+	{"interequal", funcTag, 124},
+	{"nilinterequal", funcTag, 124},
+	{"memhash", funcTag, 125},
+	{"memhash0", funcTag, 126},
+	{"memhash8", funcTag, 126},
+	{"memhash16", funcTag, 126},
+	{"memhash32", funcTag, 126},
+	{"memhash64", funcTag, 126},
+	{"memhash128", funcTag, 126},
+	{"f32hash", funcTag, 126},
+	{"f64hash", funcTag, 126},
+	{"c64hash", funcTag, 126},
+	{"c128hash", funcTag, 126},
+	{"strhash", funcTag, 126},
+	{"interhash", funcTag, 126},
+	{"nilinterhash", funcTag, 126},
+	{"int64div", funcTag, 127},
+	{"uint64div", funcTag, 128},
+	{"int64mod", funcTag, 127},
+	{"uint64mod", funcTag, 128},
+	{"float64toint64", funcTag, 129},
+	{"float64touint64", funcTag, 130},
+	{"float64touint32", funcTag, 131},
+	{"int64tofloat64", funcTag, 132},
+	{"uint64tofloat64", funcTag, 133},
+	{"uint32tofloat64", funcTag, 134},
+	{"complex128div", funcTag, 135},
+	{"getcallerpc", funcTag, 136},
+	{"getcallersp", funcTag, 136},
 	{"racefuncenter", funcTag, 31},
 	{"racefuncexit", funcTag, 9},
 	{"raceread", funcTag, 31},
 	{"racewrite", funcTag, 31},
-	{"racereadrange", funcTag, 136},
-	{"racewriterange", funcTag, 136},
-	{"msanread", funcTag, 136},
-	{"msanwrite", funcTag, 136},
-	{"msanmove", funcTag, 137},
-	{"checkptrAlignment", funcTag, 138},
-	{"checkptrArithmetic", funcTag, 140},
-	{"libfuzzerTraceCmp1", funcTag, 141},
-	{"libfuzzerTraceCmp2", funcTag, 142},
-	{"libfuzzerTraceCmp4", funcTag, 143},
-	{"libfuzzerTraceCmp8", funcTag, 144},
-	{"libfuzzerTraceConstCmp1", funcTag, 141},
-	{"libfuzzerTraceConstCmp2", funcTag, 142},
-	{"libfuzzerTraceConstCmp4", funcTag, 143},
-	{"libfuzzerTraceConstCmp8", funcTag, 144},
+	{"racereadrange", funcTag, 137},
+	{"racewriterange", funcTag, 137},
+	{"msanread", funcTag, 137},
+	{"msanwrite", funcTag, 137},
+	{"msanmove", funcTag, 138},
+	{"checkptrAlignment", funcTag, 139},
+	{"checkptrArithmetic", funcTag, 141},
+	{"libfuzzerTraceCmp1", funcTag, 142},
+	{"libfuzzerTraceCmp2", funcTag, 143},
+	{"libfuzzerTraceCmp4", funcTag, 144},
+	{"libfuzzerTraceCmp8", funcTag, 145},
+	{"libfuzzerTraceConstCmp1", funcTag, 142},
+	{"libfuzzerTraceConstCmp2", funcTag, 143},
+	{"libfuzzerTraceConstCmp4", funcTag, 144},
+	{"libfuzzerTraceConstCmp8", funcTag, 145},
 	{"x86HasPOPCNT", varTag, 6},
 	{"x86HasSSE41", varTag, 6},
 	{"x86HasFMA", varTag, 6},
@@ -224,7 +222,7 @@ func params(tlist ...*types.Type) []*types.Field {
 }
 
 func runtimeTypes() []*types.Type {
-	var typs [145]*types.Type
+	var typs [146]*types.Type
 	typs[0] = types.ByteType
 	typs[1] = types.NewPtr(typs[0])
 	typs[2] = types.Types[types.TANY]
@@ -282,93 +280,94 @@ func runtimeTypes() []*types.Type {
 	typs[54] = newSig(params(typs[3], typs[15], typs[3], typs[15], typs[5]), params(typs[15]))
 	typs[55] = newSig(params(typs[28], typs[15]), params(typs[46], typs[15]))
 	typs[56] = newSig(params(typs[28]), params(typs[15]))
-	typs[57] = newSig(params(typs[1], typs[2]), params(typs[2]))
-	typs[58] = types.Types[types.TUINT16]
-	typs[59] = newSig(params(typs[58]), params(typs[7]))
-	typs[60] = types.Types[types.TUINT32]
+	typs[57] = types.NewPtr(typs[5])
+	typs[58] = newSig(params(typs[1], typs[57]), params(typs[57]))
+	typs[59] = newSig(params(typs[1], typs[3]), params(typs[7]))
+	typs[60] = types.Types[types.TUINT16]
 	typs[61] = newSig(params(typs[60]), params(typs[7]))
-	typs[62] = newSig(params(typs[24]), params(typs[7]))
-	typs[63] = newSig(params(typs[28]), params(typs[7]))
-	typs[64] = types.Types[types.TUINT8]
-	typs[65] = types.NewSlice(typs[64])
-	typs[66] = newSig(params(typs[65]), params(typs[7]))
-	typs[67] = newSig(params(typs[1], typs[3]), params(typs[2]))
-	typs[68] = newSig(params(typs[1], typs[1]), params(typs[1]))
-	typs[69] = newSig(params(typs[1], typs[1], typs[1]), nil)
-	typs[70] = newSig(params(typs[1]), nil)
-	typs[71] = types.NewPtr(typs[5])
-	typs[72] = newSig(params(typs[71], typs[7], typs[7]), params(typs[6]))
-	typs[73] = newSig(nil, params(typs[60]))
-	typs[74] = types.NewMap(typs[2], typs[2])
-	typs[75] = newSig(params(typs[1], typs[22], typs[3]), params(typs[74]))
-	typs[76] = newSig(params(typs[1], typs[15], typs[3]), params(typs[74]))
-	typs[77] = newSig(nil, params(typs[74]))
-	typs[78] = newSig(params(typs[1], typs[74], typs[3]), params(typs[3]))
-	typs[79] = newSig(params(typs[1], typs[74], typs[60]), params(typs[3]))
-	typs[80] = newSig(params(typs[1], typs[74], typs[24]), params(typs[3]))
-	typs[81] = newSig(params(typs[1], typs[74], typs[28]), params(typs[3]))
-	typs[82] = newSig(params(typs[1], typs[74], typs[3], typs[1]), params(typs[3]))
-	typs[83] = newSig(params(typs[1], typs[74], typs[3]), params(typs[3], typs[6]))
-	typs[84] = newSig(params(typs[1], typs[74], typs[60]), params(typs[3], typs[6]))
-	typs[85] = newSig(params(typs[1], typs[74], typs[24]), params(typs[3], typs[6]))
-	typs[86] = newSig(params(typs[1], typs[74], typs[28]), params(typs[3], typs[6]))
-	typs[87] = newSig(params(typs[1], typs[74], typs[3], typs[1]), params(typs[3], typs[6]))
-	typs[88] = newSig(params(typs[1], typs[74], typs[7]), params(typs[3]))
-	typs[89] = newSig(params(typs[1], typs[74], typs[3]), nil)
-	typs[90] = newSig(params(typs[1], typs[74], typs[60]), nil)
-	typs[91] = newSig(params(typs[1], typs[74], typs[24]), nil)
-	typs[92] = newSig(params(typs[1], typs[74], typs[28]), nil)
-	typs[93] = newSig(params(typs[3]), nil)
-	typs[94] = newSig(params(typs[1], typs[74]), nil)
-	typs[95] = types.NewChan(typs[2], types.Cboth)
-	typs[96] = newSig(params(typs[1], typs[22]), params(typs[95]))
-	typs[97] = newSig(params(typs[1], typs[15]), params(typs[95]))
-	typs[98] = types.NewChan(typs[2], types.Crecv)
-	typs[99] = newSig(params(typs[98], typs[3]), nil)
-	typs[100] = newSig(params(typs[98], typs[3]), params(typs[6]))
-	typs[101] = types.NewChan(typs[2], types.Csend)
-	typs[102] = newSig(params(typs[101], typs[3]), nil)
-	typs[103] = types.NewArray(typs[0], 3)
-	typs[104] = types.NewStruct(types.NoPkg, []*types.Field{types.NewField(src.NoXPos, Lookup("enabled"), typs[6]), types.NewField(src.NoXPos, Lookup("pad"), typs[103]), types.NewField(src.NoXPos, Lookup("needed"), typs[6]), types.NewField(src.NoXPos, Lookup("cgo"), typs[6]), types.NewField(src.NoXPos, Lookup("alignme"), typs[24])})
-	typs[105] = newSig(params(typs[1], typs[3], typs[3]), nil)
-	typs[106] = newSig(params(typs[1], typs[3]), nil)
-	typs[107] = newSig(params(typs[1], typs[3], typs[15], typs[3], typs[15]), params(typs[15]))
-	typs[108] = newSig(params(typs[101], typs[3]), params(typs[6]))
-	typs[109] = newSig(params(typs[3], typs[98]), params(typs[6], typs[6]))
-	typs[110] = newSig(params(typs[71]), nil)
-	typs[111] = newSig(params(typs[1], typs[1], typs[71], typs[15], typs[15], typs[6]), params(typs[15], typs[6]))
-	typs[112] = newSig(params(typs[1], typs[15], typs[15]), params(typs[7]))
-	typs[113] = newSig(params(typs[1], typs[22], typs[22]), params(typs[7]))
-	typs[114] = newSig(params(typs[1], typs[15], typs[15], typs[7]), params(typs[7]))
-	typs[115] = types.NewSlice(typs[2])
-	typs[116] = newSig(params(typs[1], typs[115], typs[15]), params(typs[115]))
-	typs[117] = newSig(params(typs[1], typs[7], typs[15]), nil)
-	typs[118] = newSig(params(typs[1], typs[7], typs[22]), nil)
-	typs[119] = newSig(params(typs[3], typs[3], typs[5]), nil)
-	typs[120] = newSig(params(typs[7], typs[5]), nil)
-	typs[121] = newSig(params(typs[3], typs[3], typs[5]), params(typs[6]))
-	typs[122] = newSig(params(typs[3], typs[3]), params(typs[6]))
-	typs[123] = newSig(params(typs[7], typs[7]), params(typs[6]))
-	typs[124] = newSig(params(typs[7], typs[5], typs[5]), params(typs[5]))
-	typs[125] = newSig(params(typs[7], typs[5]), params(typs[5]))
-	typs[126] = newSig(params(typs[22], typs[22]), params(typs[22]))
-	typs[127] = newSig(params(typs[24], typs[24]), params(typs[24]))
-	typs[128] = newSig(params(typs[20]), params(typs[22]))
-	typs[129] = newSig(params(typs[20]), params(typs[24]))
-	typs[130] = newSig(params(typs[20]), params(typs[60]))
-	typs[131] = newSig(params(typs[22]), params(typs[20]))
-	typs[132] = newSig(params(typs[24]), params(typs[20]))
-	typs[133] = newSig(params(typs[60]), params(typs[20]))
-	typs[134] = newSig(params(typs[26], typs[26]), params(typs[26]))
-	typs[135] = newSig(nil, params(typs[5]))
-	typs[136] = newSig(params(typs[5], typs[5]), nil)
-	typs[137] = newSig(params(typs[5], typs[5], typs[5]), nil)
-	typs[138] = newSig(params(typs[7], typs[1], typs[5]), nil)
-	typs[139] = types.NewSlice(typs[7])
-	typs[140] = newSig(params(typs[7], typs[139]), nil)
-	typs[141] = newSig(params(typs[64], typs[64]), nil)
-	typs[142] = newSig(params(typs[58], typs[58]), nil)
+	typs[62] = types.Types[types.TUINT32]
+	typs[63] = newSig(params(typs[62]), params(typs[7]))
+	typs[64] = newSig(params(typs[24]), params(typs[7]))
+	typs[65] = newSig(params(typs[28]), params(typs[7]))
+	typs[66] = types.Types[types.TUINT8]
+	typs[67] = types.NewSlice(typs[66])
+	typs[68] = newSig(params(typs[67]), params(typs[7]))
+	typs[69] = newSig(params(typs[1], typs[1]), params(typs[1]))
+	typs[70] = newSig(params(typs[1], typs[2]), params(typs[2]))
+	typs[71] = newSig(params(typs[1], typs[1], typs[1]), nil)
+	typs[72] = newSig(params(typs[1]), nil)
+	typs[73] = newSig(params(typs[57], typs[7], typs[7]), params(typs[6]))
+	typs[74] = newSig(nil, params(typs[62]))
+	typs[75] = types.NewMap(typs[2], typs[2])
+	typs[76] = newSig(params(typs[1], typs[22], typs[3]), params(typs[75]))
+	typs[77] = newSig(params(typs[1], typs[15], typs[3]), params(typs[75]))
+	typs[78] = newSig(nil, params(typs[75]))
+	typs[79] = newSig(params(typs[1], typs[75], typs[3]), params(typs[3]))
+	typs[80] = newSig(params(typs[1], typs[75], typs[62]), params(typs[3]))
+	typs[81] = newSig(params(typs[1], typs[75], typs[24]), params(typs[3]))
+	typs[82] = newSig(params(typs[1], typs[75], typs[28]), params(typs[3]))
+	typs[83] = newSig(params(typs[1], typs[75], typs[3], typs[1]), params(typs[3]))
+	typs[84] = newSig(params(typs[1], typs[75], typs[3]), params(typs[3], typs[6]))
+	typs[85] = newSig(params(typs[1], typs[75], typs[62]), params(typs[3], typs[6]))
+	typs[86] = newSig(params(typs[1], typs[75], typs[24]), params(typs[3], typs[6]))
+	typs[87] = newSig(params(typs[1], typs[75], typs[28]), params(typs[3], typs[6]))
+	typs[88] = newSig(params(typs[1], typs[75], typs[3], typs[1]), params(typs[3], typs[6]))
+	typs[89] = newSig(params(typs[1], typs[75], typs[7]), params(typs[3]))
+	typs[90] = newSig(params(typs[1], typs[75], typs[3]), nil)
+	typs[91] = newSig(params(typs[1], typs[75], typs[62]), nil)
+	typs[92] = newSig(params(typs[1], typs[75], typs[24]), nil)
+	typs[93] = newSig(params(typs[1], typs[75], typs[28]), nil)
+	typs[94] = newSig(params(typs[3]), nil)
+	typs[95] = newSig(params(typs[1], typs[75]), nil)
+	typs[96] = types.NewChan(typs[2], types.Cboth)
+	typs[97] = newSig(params(typs[1], typs[22]), params(typs[96]))
+	typs[98] = newSig(params(typs[1], typs[15]), params(typs[96]))
+	typs[99] = types.NewChan(typs[2], types.Crecv)
+	typs[100] = newSig(params(typs[99], typs[3]), nil)
+	typs[101] = newSig(params(typs[99], typs[3]), params(typs[6]))
+	typs[102] = types.NewChan(typs[2], types.Csend)
+	typs[103] = newSig(params(typs[102], typs[3]), nil)
+	typs[104] = types.NewArray(typs[0], 3)
+	typs[105] = types.NewStruct(types.NoPkg, []*types.Field{types.NewField(src.NoXPos, Lookup("enabled"), typs[6]), types.NewField(src.NoXPos, Lookup("pad"), typs[104]), types.NewField(src.NoXPos, Lookup("needed"), typs[6]), types.NewField(src.NoXPos, Lookup("cgo"), typs[6]), types.NewField(src.NoXPos, Lookup("alignme"), typs[24])})
+	typs[106] = newSig(params(typs[1], typs[3], typs[3]), nil)
+	typs[107] = newSig(params(typs[1], typs[3]), nil)
+	typs[108] = newSig(params(typs[1], typs[3], typs[15], typs[3], typs[15]), params(typs[15]))
+	typs[109] = newSig(params(typs[102], typs[3]), params(typs[6]))
+	typs[110] = newSig(params(typs[3], typs[99]), params(typs[6], typs[6]))
+	typs[111] = newSig(params(typs[57]), nil)
+	typs[112] = newSig(params(typs[1], typs[1], typs[57], typs[15], typs[15], typs[6]), params(typs[15], typs[6]))
+	typs[113] = newSig(params(typs[1], typs[15], typs[15]), params(typs[7]))
+	typs[114] = newSig(params(typs[1], typs[22], typs[22]), params(typs[7]))
+	typs[115] = newSig(params(typs[1], typs[15], typs[15], typs[7]), params(typs[7]))
+	typs[116] = types.NewSlice(typs[2])
+	typs[117] = newSig(params(typs[1], typs[116], typs[15]), params(typs[116]))
+	typs[118] = newSig(params(typs[1], typs[7], typs[15]), nil)
+	typs[119] = newSig(params(typs[1], typs[7], typs[22]), nil)
+	typs[120] = newSig(params(typs[3], typs[3], typs[5]), nil)
+	typs[121] = newSig(params(typs[7], typs[5]), nil)
+	typs[122] = newSig(params(typs[3], typs[3], typs[5]), params(typs[6]))
+	typs[123] = newSig(params(typs[3], typs[3]), params(typs[6]))
+	typs[124] = newSig(params(typs[7], typs[7]), params(typs[6]))
+	typs[125] = newSig(params(typs[7], typs[5], typs[5]), params(typs[5]))
+	typs[126] = newSig(params(typs[7], typs[5]), params(typs[5]))
+	typs[127] = newSig(params(typs[22], typs[22]), params(typs[22]))
+	typs[128] = newSig(params(typs[24], typs[24]), params(typs[24]))
+	typs[129] = newSig(params(typs[20]), params(typs[22]))
+	typs[130] = newSig(params(typs[20]), params(typs[24]))
+	typs[131] = newSig(params(typs[20]), params(typs[62]))
+	typs[132] = newSig(params(typs[22]), params(typs[20]))
+	typs[133] = newSig(params(typs[24]), params(typs[20]))
+	typs[134] = newSig(params(typs[62]), params(typs[20]))
+	typs[135] = newSig(params(typs[26], typs[26]), params(typs[26]))
+	typs[136] = newSig(nil, params(typs[5]))
+	typs[137] = newSig(params(typs[5], typs[5]), nil)
+	typs[138] = newSig(params(typs[5], typs[5], typs[5]), nil)
+	typs[139] = newSig(params(typs[7], typs[1], typs[5]), nil)
+	typs[140] = types.NewSlice(typs[7])
+	typs[141] = newSig(params(typs[7], typs[140]), nil)
+	typs[142] = newSig(params(typs[66], typs[66]), nil)
 	typs[143] = newSig(params(typs[60], typs[60]), nil)
-	typs[144] = newSig(params(typs[24], typs[24]), nil)
+	typs[144] = newSig(params(typs[62], typs[62]), nil)
+	typs[145] = newSig(params(typs[24], typs[24]), nil)
 	return typs[:]
 }
diff --git a/src/cmd/compile/internal/typecheck/builtin/runtime.go b/src/cmd/compile/internal/typecheck/builtin/runtime.go
index 2b29ea3c08..605b904288 100644
--- a/src/cmd/compile/internal/typecheck/builtin/runtime.go
+++ b/src/cmd/compile/internal/typecheck/builtin/runtime.go
@@ -84,10 +84,15 @@ func decoderune(string, int) (retv rune, retk int)
 func countrunes(string) int
 
 // Non-empty-interface to non-empty-interface conversion.
-func convI2I(typ *byte, elem any) (ret any)
+func convI2I(typ *byte, itab *uintptr) (ret *uintptr)
 
-// Specialized type-to-interface conversion.
-// These return only a data pointer.
+// Convert non-interface type to the data word of a (empty or nonempty) interface.
+func convT(typ *byte, elem *any) unsafe.Pointer
+
+// Same as convT, for types with no pointers in them.
+func convTnoptr(typ *byte, elem *any) unsafe.Pointer
+
+// Specialized versions of convT for specific types.
 // These functions take concrete types in the runtime. But they may
 // be used for a wider range of types, which have the same memory
 // layout as the parameter type. The compiler converts the
@@ -99,14 +104,6 @@ func convT64(val uint64) unsafe.Pointer
 func convTstring(val string) unsafe.Pointer
 func convTslice(val []uint8) unsafe.Pointer
 
-// Type to empty-interface conversion.
-func convT2E(typ *byte, elem *any) (ret any)
-func convT2Enoptr(typ *byte, elem *any) (ret any)
-
-// Type to non-empty-interface conversion.
-func convT2I(tab *byte, elem *any) (ret any)
-func convT2Inoptr(tab *byte, elem *any) (ret any)
-
 // interface type assertions x.(T)
 func assertE2I(inter *byte, typ *byte) *byte
 func assertE2I2(inter *byte, eface any) (ret any)
diff --git a/src/cmd/compile/internal/walk/convert.go b/src/cmd/compile/internal/walk/convert.go
index d15575f643..27a07ce4b6 100644
--- a/src/cmd/compile/internal/walk/convert.go
+++ b/src/cmd/compile/internal/walk/convert.go
@@ -39,56 +39,100 @@ func walkConv(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
 	return typecheck.Conv(mkcall(fn, types.Types[result], init, typecheck.Conv(n.X, types.Types[param])), n.Type())
 }
 
-// walkConvInterface walks an OCONVIFACE or OCONVIDATA node.
+// walkConvInterface walks an OCONVIFACE node.
 func walkConvInterface(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
 
 	n.X = walkExpr(n.X, init)
 
 	fromType := n.X.Type()
 	toType := n.Type()
-	if n.Op() == ir.OCONVIDATA {
-		// Just convert to empty interface, to make it easy.
-		// The caller throws away the type word.
-		toType = types.NewInterface(types.LocalPkg, nil)
-		// Note: don't pass fromType to MarkTypeUsedInInterface because it is likely
-		// a shape type. The appropriate call to MarkTypeUsedInInterface will come
-		// when building the dictionary (from which the matching type word will come).
-	} else if !fromType.IsInterface() && !ir.IsBlank(ir.CurFunc.Nname) {
+	if !fromType.IsInterface() && !ir.IsBlank(ir.CurFunc.Nname) {
 		// skip unnamed functions (func _())
 		reflectdata.MarkTypeUsedInInterface(fromType, ir.CurFunc.LSym)
 	}
 
-	// typeword generates the type word of the interface value.
-	typeword := func() ir.Node {
+	if !fromType.IsInterface() {
+		var typeWord ir.Node
 		if toType.IsEmptyInterface() {
-			return reflectdata.TypePtr(fromType)
+			typeWord = reflectdata.TypePtr(fromType)
+		} else {
+			typeWord = reflectdata.ITabAddr(fromType, toType)
 		}
-		return reflectdata.ITabAddr(fromType, toType)
-	}
-
-	// Optimize convT2E or convT2I as a two-word copy when T is pointer-shaped.
-	if types.IsDirectIface(fromType) {
-		l := ir.NewBinaryExpr(base.Pos, ir.OEFACE, typeword(), n.X)
+		l := ir.NewBinaryExpr(base.Pos, ir.OEFACE, typeWord, dataWord(n.X, init, n.Esc() != ir.EscNone))
 		l.SetType(toType)
 		l.SetTypecheck(n.Typecheck())
 		return l
 	}
+	if fromType.IsEmptyInterface() {
+		base.Fatalf("OCONVIFACE can't operate on an empty interface")
+	}
+
+	// Evaluate the input interface.
+	c := typecheck.Temp(fromType)
+	init.Append(ir.NewAssignStmt(base.Pos, c, n.X))
+
+	// Grab its parts.
+	itab := ir.NewUnaryExpr(base.Pos, ir.OITAB, c)
+	itab.SetType(types.Types[types.TUINTPTR].PtrTo())
+	itab.SetTypecheck(1)
+	data := ir.NewUnaryExpr(base.Pos, ir.OIDATA, c)
+	data.SetType(types.Types[types.TUINT8].PtrTo()) // Type is generic pointer - we're just passing it through.
+	data.SetTypecheck(1)
+
+	var typeWord ir.Node
+	if toType.IsEmptyInterface() {
+		// Implement interface to empty interface conversion.
+		// res = itab
+		// if res != nil {
+		//    res = res.type
+		// }
+		typeWord = typecheck.Temp(types.NewPtr(types.Types[types.TUINT8]))
+		init.Append(ir.NewAssignStmt(base.Pos, typeWord, itab))
+		nif := ir.NewIfStmt(base.Pos, typecheck.Expr(ir.NewBinaryExpr(base.Pos, ir.ONE, typeWord, typecheck.NodNil())), nil, nil)
+		nif.Body = []ir.Node{ir.NewAssignStmt(base.Pos, typeWord, itabType(typeWord))}
+		init.Append(nif)
+	} else {
+		// Must be converting I2I (more specific to less specific interface).
+		// res = convI2I(toType, itab)
+		fn := typecheck.LookupRuntime("convI2I")
+		types.CalcSize(fn.Type())
+		call := ir.NewCallExpr(base.Pos, ir.OCALL, fn, nil)
+		call.Args = []ir.Node{reflectdata.TypePtr(toType), itab}
+		typeWord = walkExpr(typecheck.Expr(call), init)
+	}
+
+	// Build the result.
+	// e = iface{typeWord, data}
+	e := ir.NewBinaryExpr(base.Pos, ir.OEFACE, typeWord, data)
+	e.SetType(toType) // assign type manually, typecheck doesn't understand OEFACE.
+	e.SetTypecheck(1)
+	return e
+}
+
+// Returns the data word (the second word) used to represent n in an interface.
+// n must not be of interface type.
+// esc describes whether the result escapes.
+func dataWord(n ir.Node, init *ir.Nodes, escapes bool) ir.Node {
+	fromType := n.Type()
+
+	// If it's a pointer, it is its own representation.
+	if types.IsDirectIface(fromType) {
+		return n
+	}
 
-	// Optimize convT2{E,I} for many cases in which T is not pointer-shaped,
-	// by using an existing addressable value identical to n.Left
-	// or creating one on the stack.
+	// Try a bunch of cases to avoid an allocation.
 	var value ir.Node
 	switch {
 	case fromType.Size() == 0:
-		// n.Left is zero-sized. Use zerobase.
-		cheapExpr(n.X, init) // Evaluate n.Left for side-effects. See issue 19246.
+		// n is zero-sized. Use zerobase.
+		cheapExpr(n, init) // Evaluate n for side-effects. See issue 19246.
 		value = ir.NewLinksymExpr(base.Pos, ir.Syms.Zerobase, types.Types[types.TUINTPTR])
 	case fromType.IsBoolean() || (fromType.Size() == 1 && fromType.IsInteger()):
-		// n.Left is a bool/byte. Use staticuint64s[n.Left * 8] on little-endian
-		// and staticuint64s[n.Left * 8 + 7] on big-endian.
-		n.X = cheapExpr(n.X, init)
-		// byteindex widens n.Left so that the multiplication doesn't overflow.
-		index := ir.NewBinaryExpr(base.Pos, ir.OLSH, byteindex(n.X), ir.NewInt(3))
+		// n is a bool/byte. Use staticuint64s[n * 8] on little-endian
+		// and staticuint64s[n * 8 + 7] on big-endian.
+		n = cheapExpr(n, init)
+		// byteindex widens n so that the multiplication doesn't overflow.
+		index := ir.NewBinaryExpr(base.Pos, ir.OLSH, byteindex(n), ir.NewInt(3))
 		if ssagen.Arch.LinkArch.ByteOrder == binary.BigEndian {
 			index = ir.NewBinaryExpr(base.Pos, ir.OADD, index, ir.NewInt(7))
 		}
@@ -98,118 +142,71 @@ func walkConvInterface(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
 		xe := ir.NewIndexExpr(base.Pos, staticuint64s, index)
 		xe.SetBounded(true)
 		value = xe
-	case n.X.Op() == ir.ONAME && n.X.(*ir.Name).Class == ir.PEXTERN && n.X.(*ir.Name).Readonly():
-		// n.Left is a readonly global; use it directly.
-		value = n.X
-	case !fromType.IsInterface() && n.Esc() == ir.EscNone && fromType.Width <= 1024:
-		// n.Left does not escape. Use a stack temporary initialized to n.Left.
+	case n.Op() == ir.ONAME && n.(*ir.Name).Class == ir.PEXTERN && n.(*ir.Name).Readonly():
+		// n is a readonly global; use it directly.
+		value = n
+	case !escapes && fromType.Width <= 1024:
+		// n does not escape. Use a stack temporary initialized to n.
 		value = typecheck.Temp(fromType)
-		init.Append(typecheck.Stmt(ir.NewAssignStmt(base.Pos, value, n.X)))
+		init.Append(typecheck.Stmt(ir.NewAssignStmt(base.Pos, value, n)))
 	}
-
 	if value != nil {
-		// Value is identical to n.Left.
-		// Construct the interface directly: {type/itab, &value}.
-		l := ir.NewBinaryExpr(base.Pos, ir.OEFACE, typeword(), typecheck.Expr(typecheck.NodAddr(value)))
-		l.SetType(toType)
-		l.SetTypecheck(n.Typecheck())
-		return l
-	}
-
-	// Implement interface to empty interface conversion.
-	// tmp = i.itab
-	// if tmp != nil {
-	//    tmp = tmp.type
-	// }
-	// e = iface{tmp, i.data}
-	if toType.IsEmptyInterface() && fromType.IsInterface() && !fromType.IsEmptyInterface() {
-		// Evaluate the input interface.
-		c := typecheck.Temp(fromType)
-		init.Append(ir.NewAssignStmt(base.Pos, c, n.X))
-
-		// Get the itab out of the interface.
-		tmp := typecheck.Temp(types.NewPtr(types.Types[types.TUINT8]))
-		init.Append(ir.NewAssignStmt(base.Pos, tmp, typecheck.Expr(ir.NewUnaryExpr(base.Pos, ir.OITAB, c))))
-
-		// Get the type out of the itab.
-		nif := ir.NewIfStmt(base.Pos, typecheck.Expr(ir.NewBinaryExpr(base.Pos, ir.ONE, tmp, typecheck.NodNil())), nil, nil)
-		nif.Body = []ir.Node{ir.NewAssignStmt(base.Pos, tmp, itabType(tmp))}
-		init.Append(nif)
-
-		// Build the result.
-		e := ir.NewBinaryExpr(base.Pos, ir.OEFACE, tmp, ifaceData(n.Pos(), c, types.NewPtr(types.Types[types.TUINT8])))
-		e.SetType(toType) // assign type manually, typecheck doesn't understand OEFACE.
-		e.SetTypecheck(1)
-		return e
+		// The interface data word is &value.
+		return typecheck.Expr(typecheck.NodAddr(value))
 	}
 
-	fnname, argType, needsaddr := convFuncName(fromType, toType)
-
-	if !needsaddr && !fromType.IsInterface() {
-		// Use a specialized conversion routine that only returns a data pointer.
-		// ptr = convT2X(val)
-		// e = iface{typ/tab, ptr}
-		fn := typecheck.LookupRuntime(fnname)
-		types.CalcSize(fromType)
+	// Time to do an allocation. We'll call into the runtime for that.
+	fnname, argType, needsaddr := dataWordFuncName(fromType)
+	fn := typecheck.LookupRuntime(fnname)
 
-		arg := n.X
+	var args []ir.Node
+	if needsaddr {
+		// Types of large or unknown size are passed by reference.
+		// Orderexpr arranged for n to be a temporary for all
+		// the conversions it could see. Comparison of an interface
+		// with a non-interface, especially in a switch on interface value
+		// with non-interface cases, is not visible to order.stmt, so we
+		// have to fall back on allocating a temp here.
+		if !ir.IsAddressable(n) {
+			n = copyExpr(n, fromType, init)
+		}
+		fn = typecheck.SubstArgTypes(fn, fromType)
+		args = []ir.Node{reflectdata.TypePtr(fromType), typecheck.NodAddr(n)}
+	} else {
+		// Use a specialized conversion routine that takes the type being
+		// converted by value, not by pointer.
+		var arg ir.Node
 		switch {
 		case fromType == argType:
 			// already in the right type, nothing to do
+			arg = n
 		case fromType.Kind() == argType.Kind(),
 			fromType.IsPtrShaped() && argType.IsPtrShaped():
 			// can directly convert (e.g. named type to underlying type, or one pointer to another)
-			arg = ir.NewConvExpr(n.Pos(), ir.OCONVNOP, argType, arg)
+			// TODO: never happens because pointers are directIface?
+			arg = ir.NewConvExpr(n.Pos(), ir.OCONVNOP, argType, n)
 		case fromType.IsInteger() && argType.IsInteger():
 			// can directly convert (e.g. int32 to uint32)
-			arg = ir.NewConvExpr(n.Pos(), ir.OCONV, argType, arg)
+			arg = ir.NewConvExpr(n.Pos(), ir.OCONV, argType, n)
 		default:
 			// unsafe cast through memory
-			arg = copyExpr(arg, arg.Type(), init)
+			arg = copyExpr(n, fromType, init)
 			var addr ir.Node = typecheck.NodAddr(arg)
 			addr = ir.NewConvExpr(n.Pos(), ir.OCONVNOP, argType.PtrTo(), addr)
 			arg = ir.NewStarExpr(n.Pos(), addr)
 			arg.SetType(argType)
 		}
-
-		call := ir.NewCallExpr(base.Pos, ir.OCALL, fn, nil)
-		call.Args = []ir.Node{arg}
-		e := ir.NewBinaryExpr(base.Pos, ir.OEFACE, typeword(), safeExpr(walkExpr(typecheck.Expr(call), init), init))
-		e.SetType(toType)
-		e.SetTypecheck(1)
-		return e
-	}
-
-	var tab ir.Node
-	if fromType.IsInterface() {
-		// convI2I
-		tab = reflectdata.TypePtr(toType)
-	} else {
-		// convT2x
-		tab = typeword()
-	}
-
-	v := n.X
-	if needsaddr {
-		// Types of large or unknown size are passed by reference.
-		// Orderexpr arranged for n.Left to be a temporary for all
-		// the conversions it could see. Comparison of an interface
-		// with a non-interface, especially in a switch on interface value
-		// with non-interface cases, is not visible to order.stmt, so we
-		// have to fall back on allocating a temp here.
-		if !ir.IsAddressable(v) {
-			v = copyExpr(v, v.Type(), init)
-		}
-		v = typecheck.NodAddr(v)
+		args = []ir.Node{arg}
 	}
-
-	types.CalcSize(fromType)
-	fn := typecheck.LookupRuntime(fnname)
-	fn = typecheck.SubstArgTypes(fn, fromType, toType)
-	types.CalcSize(fn.Type())
 	call := ir.NewCallExpr(base.Pos, ir.OCALL, fn, nil)
-	call.Args = []ir.Node{tab, v}
-	return walkExpr(typecheck.Expr(call), init)
+	call.Args = args
+	return safeExpr(walkExpr(typecheck.Expr(call), init), init)
+}
+
+// walkConvIData walks an OCONVIDATA node.
+func walkConvIData(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
+	n.X = walkExpr(n.X, init)
+	return dataWord(n.X, init, n.Esc() != ir.EscNone)
 }
 
 // walkBytesRunesToString walks an OBYTES2STR or ORUNES2STR node.
@@ -320,50 +317,35 @@ func walkStringToRunes(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
 	return mkcall("stringtoslicerune", n.Type(), init, a, typecheck.Conv(n.X, types.Types[types.TSTRING]))
 }
 
-// convFuncName builds the runtime function name for interface conversion.
-// It also returns the argument type that the runtime function takes, and
-// whether the function expects the data by address.
-// Not all names are possible. For example, we never generate convE2E or convE2I.
-func convFuncName(from, to *types.Type) (fnname string, argType *types.Type, needsaddr bool) {
-	tkind := to.Tie()
-	switch from.Tie() {
-	case 'I':
-		if tkind == 'I' {
-			return "convI2I", types.Types[types.TINTER], false
-		}
-	case 'T':
+// dataWordFuncName returns the name of the function used to convert a value of type "from"
+// to the data word of an interface.
+// argType is the type the argument needs to be coerced to.
+// needsaddr reports whether the value should be passed (needaddr==false) or its address (needsaddr==true).
+func dataWordFuncName(from *types.Type) (fnname string, argType *types.Type, needsaddr bool) {
+	if from.IsInterface() {
+		base.Fatalf("can only handle non-interfaces")
+	}
+	switch {
+	case from.Size() == 2 && from.Align == 2:
+		return "convT16", types.Types[types.TUINT16], false
+	case from.Size() == 4 && from.Align == 4 && !from.HasPointers():
+		return "convT32", types.Types[types.TUINT32], false
+	case from.Size() == 8 && from.Align == types.Types[types.TUINT64].Align && !from.HasPointers():
+		return "convT64", types.Types[types.TUINT64], false
+	}
+	if sc := from.SoleComponent(); sc != nil {
 		switch {
-		case from.Size() == 2 && from.Align == 2:
-			return "convT16", types.Types[types.TUINT16], false
-		case from.Size() == 4 && from.Align == 4 && !from.HasPointers():
-			return "convT32", types.Types[types.TUINT32], false
-		case from.Size() == 8 && from.Align == types.Types[types.TUINT64].Align && !from.HasPointers():
-			return "convT64", types.Types[types.TUINT64], false
-		}
-		if sc := from.SoleComponent(); sc != nil {
-			switch {
-			case sc.IsString():
-				return "convTstring", types.Types[types.TSTRING], false
-			case sc.IsSlice():
-				return "convTslice", types.NewSlice(types.Types[types.TUINT8]), false // the element type doesn't matter
-			}
+		case sc.IsString():
+			return "convTstring", types.Types[types.TSTRING], false
+		case sc.IsSlice():
+			return "convTslice", types.NewSlice(types.Types[types.TUINT8]), false // the element type doesn't matter
 		}
+	}
 
-		switch tkind {
-		case 'E':
-			if !from.HasPointers() {
-				return "convT2Enoptr", types.Types[types.TUNSAFEPTR], true
-			}
-			return "convT2E", types.Types[types.TUNSAFEPTR], true
-		case 'I':
-			if !from.HasPointers() {
-				return "convT2Inoptr", types.Types[types.TUNSAFEPTR], true
-			}
-			return "convT2I", types.Types[types.TUNSAFEPTR], true
-		}
+	if from.HasPointers() {
+		return "convT", types.Types[types.TUNSAFEPTR], true
 	}
-	base.Fatalf("unknown conv func %c2%c", from.Tie(), to.Tie())
-	panic("unreachable")
+	return "convTnoptr", types.Types[types.TUNSAFEPTR], true
 }
 
 // rtconvfn returns the parameter and result types that will be used by a
diff --git a/src/cmd/compile/internal/walk/expr.go b/src/cmd/compile/internal/walk/expr.go
index f95b6f4639..26e225440a 100644
--- a/src/cmd/compile/internal/walk/expr.go
+++ b/src/cmd/compile/internal/walk/expr.go
@@ -212,10 +212,7 @@ func walkExpr1(n ir.Node, init *ir.Nodes) ir.Node {
 
 	case ir.OCONVIDATA:
 		n := n.(*ir.ConvExpr)
-		r := ir.NewUnaryExpr(n.Pos(), ir.OIDATA, walkConvInterface(n, init))
-		r.SetType(types.Types[types.TUNSAFEPTR])
-		r.SetTypecheck(1)
-		return r
+		return walkConvIData(n, init)
 
 	case ir.OCONV, ir.OCONVNOP:
 		n := n.(*ir.ConvExpr)
diff --git a/src/cmd/compile/internal/walk/order.go b/src/cmd/compile/internal/walk/order.go
index c5fd0c1e1d..6e336f565c 100644
--- a/src/cmd/compile/internal/walk/order.go
+++ b/src/cmd/compile/internal/walk/order.go
@@ -1166,11 +1166,7 @@ func (o *orderState) expr1(n, lhs ir.Node) ir.Node {
 		if n.X.Type().IsInterface() {
 			return n
 		}
-		to := n.Type()
-		if n.Op() == ir.OCONVIDATA {
-			to = types.NewInterface(types.LocalPkg, nil)
-		}
-		if _, _, needsaddr := convFuncName(n.X.Type(), to); needsaddr || isStaticCompositeLiteral(n.X) {
+		if _, _, needsaddr := dataWordFuncName(n.X.Type()); needsaddr || isStaticCompositeLiteral(n.X) {
 			// Need a temp if we need to pass the address to the conversion function.
 			// We also process static composite literal node here, making a named static global
 			// whose address we can put directly in an interface (see OCONVIFACE/OCONVIDATA case in walk).
diff --git a/src/runtime/iface.go b/src/runtime/iface.go
index 79a49c0dff..3d1d9d6ba1 100644
--- a/src/runtime/iface.go
+++ b/src/runtime/iface.go
@@ -316,20 +316,30 @@ var (
 // The convXXX functions succeed on a nil input, whereas the assertXXX
 // functions fail on a nil input.
 
-func convT2E(t *_type, elem unsafe.Pointer) (e eface) {
+// convT converts a value of type t, which is pointed to by v, to a pointer that can
+// be used as the second word of an interface value.
+func convT(t *_type, v unsafe.Pointer) unsafe.Pointer {
 	if raceenabled {
-		raceReadObjectPC(t, elem, getcallerpc(), abi.FuncPCABIInternal(convT2E))
+		raceReadObjectPC(t, v, getcallerpc(), abi.FuncPCABIInternal(convT))
 	}
 	if msanenabled {
-		msanread(elem, t.size)
+		msanread(v, t.size)
 	}
 	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
+	typedmemmove(t, x, v)
+	return x
+}
+func convTnoptr(t *_type, v unsafe.Pointer) unsafe.Pointer {
+	// TODO: maybe take size instead of type?
+	if raceenabled {
+		raceReadObjectPC(t, v, getcallerpc(), abi.FuncPCABIInternal(convTnoptr))
+	}
+	if msanenabled {
+		msanread(v, t.size)
+	}
+	x := mallocgc(t.size, t, false)
+	memmove(x, v, t.size)
+	return x
 }
 
 func convT16(val uint16) (x unsafe.Pointer) {
@@ -389,63 +399,16 @@ func convTslice(val []byte) (x unsafe.Pointer) {
 	return
 }
 
-func convT2Enoptr(t *_type, elem unsafe.Pointer) (e eface) {
-	if raceenabled {
-		raceReadObjectPC(t, elem, getcallerpc(), abi.FuncPCABIInternal(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 {
-		raceReadObjectPC(t, elem, getcallerpc(), abi.FuncPCABIInternal(convT2I))
-	}
-	if msanenabled {
-		msanread(elem, t.size)
-	}
-	x := mallocgc(t.size, t, true)
-	typedmemmove(t, x, 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(), abi.FuncPCABIInternal(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 {
-		return
+// convI2I returns the new itab to be used for the destination value
+// when converting a value with itab src to the dst interface.
+func convI2I(dst *interfacetype, src *itab) *itab {
+	if src == nil {
+		return nil
 	}
-	if tab.inter == inter {
-		r.tab = tab
-		r.data = i.data
-		return
+	if src.inter == dst {
+		return src
 	}
-	r.tab = getitab(inter, tab._type, false)
-	r.data = i.data
-	return
+	return getitab(dst, src._type, false)
 }
 
 func assertI2I(inter *interfacetype, tab *itab) *itab {
diff --git a/test/devirt.go b/test/devirt.go
index e0149d8229..d5c815222e 100644
--- a/test/devirt.go
+++ b/test/devirt.go
@@ -31,9 +31,8 @@ func main() {
 		panic("not 3")
 	}
 
-	// Can't do types that aren't "direct" interfaces (yet).
 	r = indirectiface{3, 4, 5}
-	if r.Value() != 12 {
+	if r.Value() != 12 { // ERROR "de-virtualizing call$"
 		panic("not 12")
 	}
 }
diff --git a/test/fixedbugs/issue20250.go b/test/fixedbugs/issue20250.go
index 1a513bea56..aed7b25d1b 100644
--- a/test/fixedbugs/issue20250.go
+++ b/test/fixedbugs/issue20250.go
@@ -17,7 +17,7 @@ type T struct {
 func f(a T) { // ERROR "live at entry to f: a"
 	var e interface{} // ERROR "stack object e interface \{\}$"
 	func() {          // ERROR "live at entry to f.func1: a &e"
-		e = a.s // ERROR "live at call to convT2E: &e" "stack object a T$"
+		e = a.s // ERROR "live at call to convT: &e" "stack object a T$"
 	}()
 	// Before the fix, both a and e were live at the previous line.
 	_ = e
diff --git a/test/live.go b/test/live.go
index 856e56f3d2..6130f7f069 100644
--- a/test/live.go
+++ b/test/live.go
@@ -144,8 +144,8 @@ var i9 interface{}
 func f9() bool {
 	g8()
 	x := i9
-	y := interface{}(g18()) // ERROR "live at call to convT2E: x.data$" "live at call to g18: x.data$" "stack object .autotmp_[0-9]+ \[2\]string$"
-	i9 = y                  // make y escape so the line above has to call convT2E
+	y := interface{}(g18()) // ERROR "live at call to convT: x.data$" "live at call to g18: x.data$" "stack object .autotmp_[0-9]+ \[2\]string$"
+	i9 = y                  // make y escape so the line above has to call convT
 	return x != y
 }
 
@@ -503,7 +503,7 @@ func f31(b1, b2, b3 bool) {
 		g31(g18()) // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
 	}
 	if b2 {
-		h31(g18()) // ERROR "live at call to convT2E: .autotmp_[0-9]+$" "live at call to newobject: .autotmp_[0-9]+$"
+		h31(g18()) // ERROR "live at call to convT: .autotmp_[0-9]+$" "live at call to newobject: .autotmp_[0-9]+$"
 	}
 	if b3 {
 		panic(g18())
diff --git a/test/live_regabi.go b/test/live_regabi.go
index d362ee287d..2883b83bae 100644
--- a/test/live_regabi.go
+++ b/test/live_regabi.go
@@ -139,8 +139,8 @@ var i9 interface{}
 func f9() bool {
 	g8()
 	x := i9
-	y := interface{}(g18()) // ERROR "live at call to convT2E: x.data$" "live at call to g18: x.data$" "stack object .autotmp_[0-9]+ \[2\]string$"
-	i9 = y                  // make y escape so the line above has to call convT2E
+	y := interface{}(g18()) // ERROR "live at call to convT: x.data$" "live at call to g18: x.data$" "stack object .autotmp_[0-9]+ \[2\]string$"
+	i9 = y                  // make y escape so the line above has to call convT
 	return x != y
 }
 
@@ -498,7 +498,7 @@ func f31(b1, b2, b3 bool) {
 		g31(g18()) // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
 	}
 	if b2 {
-		h31(g18()) // ERROR "live at call to convT2E: .autotmp_[0-9]+$" "live at call to newobject: .autotmp_[0-9]+$"
+		h31(g18()) // ERROR "live at call to convT: .autotmp_[0-9]+$" "live at call to newobject: .autotmp_[0-9]+$"
 	}
 	if b3 {
 		panic(g18())