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[BugFix] Fix FP4 related vectorized cast #1741

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Merged
LeiWang1999 merged 1 commit into from
Jan 27, 2026
Merged

[BugFix] Fix FP4 related vectorized cast #1741

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11 changes: 7 additions & 4 deletions src/target/codegen_cuda.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -1244,7 +1244,8 @@ void CodeGenTileLangCUDA::VisitExpr_(const CastNode *op, std::ostream &os) {
}

// Handle conversion from float8 (E4M3/E5M2) to float32
if (tl::IsCudaVectorizableFP8(from_ty) && target_ty.is_float()) {
if (tl::IsCudaVectorizableFP8(from_ty) && target_ty.is_float() &&
target_ty.bits() == 32) {
bool from_type_is_e4m3 =
from_ty.is_float8_e4m3() || from_ty.is_float8_e4m3fn();
std::string type_suffix = from_type_is_e4m3 ? "__NV_E4M3" : "__NV_E5M2";
Expand Down Expand Up @@ -1280,7 +1281,7 @@ void CodeGenTileLangCUDA::VisitExpr_(const CastNode *op, std::ostream &os) {
}
}

// Handle conversion from float to float8 (E8M0)
// Handle conversion from float32 to float8 (E8M0)
if (from_ty.is_float() && from_ty.bits() == 32 &&
target_ty.is_float8_e8m0fnu()) {
// Use __tl_cvt_float2_to_e8m0x2 for vectorized conversion (float2 ->
Expand Down Expand Up @@ -1315,7 +1316,8 @@ void CodeGenTileLangCUDA::VisitExpr_(const CastNode *op, std::ostream &os) {
}

// Handle conversion from float32 to float4 (E2M1)
if (from_ty.is_float() && target_ty.is_float4_e2m1fn()) {
if (from_ty.is_float() && from_ty.bits() == 32 &&
target_ty.is_float4_e2m1fn()) {
// Use __tl_cvt_float2_to_fp4x2 for vectorized conversion (float2 -> fp4x2)
if (lanes == 2 || lanes == 4 || lanes == 8) {
PrintVectorizedCast("__tl_cvt_float2_to_fp4x2", "float2", "uint8_t", "",
Expand All @@ -1335,7 +1337,8 @@ void CodeGenTileLangCUDA::VisitExpr_(const CastNode *op, std::ostream &os) {
}

// Handle conversion from float4 (E2M1) to float32
if (from_ty.is_float4_e2m1fn() && target_ty.is_float()) {
if (from_ty.is_float4_e2m1fn() && target_ty.is_float() &&
target_ty.bits() == 32) {
// Use __tl_cvt_fp4x2_to_float2 for vectorized conversion (fp4x2 -> float2)
if (lanes == 2 || lanes == 4 || lanes == 8) {
PrintVectorizedCast("__tl_cvt_fp4x2_to_float2", "uint8_t", "float2", "",
Expand Down
68 changes: 58 additions & 10 deletions src/target/utils.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -162,29 +162,43 @@ bool IsCudaVectorizableFP8(DataType dtype) {

bool IsCudaVectorizableCast(DataType from_ty, DataType target_ty) {
// float16 -> float32
if (from_ty.is_float16() && target_ty.is_float())
if (from_ty.is_float16() && target_ty.is_float() && target_ty.bits() == 32)
return true;

// float32 -> float16
if (from_ty.is_float() && target_ty.is_float16())
if (from_ty.is_float() && from_ty.bits() == 32 && target_ty.is_float16())
return true;

// bfloat16 -> float32
if (from_ty.is_bfloat16() && target_ty.is_float())
if (from_ty.is_bfloat16() && target_ty.is_float() && target_ty.bits() == 32)
return true;

// float32 -> bfloat16
if (from_ty.is_float() && target_ty.is_bfloat16())
if (from_ty.is_float() && from_ty.bits() == 32 && target_ty.is_bfloat16())
return true;

// float32 -> float8 (E4M3/E5M2)
if (from_ty.is_float() && IsCudaVectorizableFP8(target_ty))
if (from_ty.is_float() && from_ty.bits() == 32 &&
IsCudaVectorizableFP8(target_ty))
return true;

// float8 (E4M3/E5M2) -> float32
if (IsCudaVectorizableFP8(from_ty) && target_ty.is_float())
if (IsCudaVectorizableFP8(from_ty) && target_ty.is_float() &&
target_ty.bits() == 32)
return true;

// Not implemented for now

// float64(double) -> float8 (E4M3/E5M2)
// if (from_ty.is_float() && from_ty.bits() == 64 &&
// IsCudaVectorizableFP8(target_ty))
// return true;

// float8 (E4M3/E5M2) -> float64(double)
// if (IsCudaVectorizableFP8(from_ty) && target_ty.is_float() &&
// target_ty.bits() == 64)
// return true;

// float8 (E8M0) -> bfloat16
if (from_ty.is_float8_e8m0fnu() && target_ty.is_bfloat16())
return true;
Expand All @@ -193,16 +207,50 @@ bool IsCudaVectorizableCast(DataType from_ty, DataType target_ty) {
if (from_ty.is_bfloat16() && target_ty.is_float8_e8m0fnu())
return true;

// float32/double -> float8 (E8M0)
if (from_ty.is_float() && target_ty.is_float8_e8m0fnu())
// float32 -> float8 (E8M0)
if (from_ty.is_float() && from_ty.bits() == 32 &&
target_ty.is_float8_e8m0fnu())
return true;

// float64(double) -> float8 (E8M0)
if (from_ty.is_float() && from_ty.bits() == 64 &&
target_ty.is_float8_e8m0fnu())
return true;

// float4_e2m1fn -> float16
if (from_ty.is_float4_e2m1fn() && target_ty.is_float16())
return true;

// float16 -> float4_e2m1fn
if (from_ty.is_float16() && target_ty.is_float4_e2m1fn())
return true;

// float4_e2m1fn -> float32
if (from_ty.is_float4_e2m1fn() && target_ty.is_float())
if (from_ty.is_float4_e2m1fn() && target_ty.is_float() &&
target_ty.bits() == 32)
return true;

// float32 -> float4_e2m1fn
if (from_ty.is_float() && target_ty.is_float4_e2m1fn())
if (from_ty.is_float() && from_ty.bits() == 32 &&
target_ty.is_float4_e2m1fn())
return true;

// float4_e2m1fn -> float64(double)
if (from_ty.is_float4_e2m1fn() && target_ty.is_float() &&
target_ty.bits() == 64)
return true;

// float64(double) -> float4_e2m1fn
if (from_ty.is_float() && from_ty.bits() == 64 &&
target_ty.is_float4_e2m1fn())
return true;

// float4_e2m1fn -> bfloat16
if (from_ty.is_float4_e2m1fn() && target_ty.is_bfloat16())
return true;

// bfloat16 -> float4_e2m1fn
if (from_ty.is_bfloat16() && target_ty.is_float4_e2m1fn())
return true;

return false;
Expand Down
9 changes: 5 additions & 4 deletions testing/python/language/test_tilelang_language_vectorized_cast.py
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Original file line number Diff line number Diff line change
Expand Up @@ -86,10 +86,6 @@ def run_vectorized_cast(src_dtype: T.dtype, dst_dtype: T.dtype, check_str: str,
(T.float32, T.float16, "__float22half2_rn", 4),
(T.float16, T.float32, "__half22float2", 2),
(T.float16, T.float32, "__half22float2", 4),
(T.float32, T.float8_e4m3fn, "__nv_cvt_float2_to_fp8x2", 2),
(T.float32, T.float8_e4m3fn, "__nv_cvt_float2_to_fp8x2", 4),
(T.float32, T.float8_e5m2, "__nv_cvt_float2_to_fp8x2", 2),
(T.float32, T.float8_e5m2, "__nv_cvt_float2_to_fp8x2", 4),
(T.float32, T.bfloat16, "__float22bfloat162_rn", 2),
(T.float32, T.bfloat16, "__float22bfloat162_rn", 4),
(T.bfloat16, T.float32, "__bfloat1622float2", 2),
Expand All @@ -105,6 +101,11 @@ def test_vectorized_cast(src_dtype, dst_dtype, check_str, lanes):
@pytest.mark.parametrize(
"src_dtype, dst_dtype, check_str, lanes",
[
# FP8 <-> FP32
(T.float32, T.float8_e4m3fn, "__nv_cvt_float2_to_fp8x2", 2),
(T.float32, T.float8_e4m3fn, "__nv_cvt_float2_to_fp8x2", 4),
(T.float32, T.float8_e5m2, "__nv_cvt_float2_to_fp8x2", 2),
(T.float32, T.float8_e5m2, "__nv_cvt_float2_to_fp8x2", 4),
(T.float8_e4m3fn, T.float32, "__tl_cvt_fp8x2_to_float2", 2),
(T.float8_e4m3fn, T.float32, "__tl_cvt_fp8x2_to_float2", 4),
(T.float8_e5m2, T.float32, "__tl_cvt_fp8x2_to_float2", 2),
Expand Down
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