Add test case & make arith-to-spirv use emulation flag.

Author: mshahneo

mlir/lib/Conversion/ArithToSPIRV/ArithToSPIRV.cpp

@@ -306,7 +306,9 @@ struct ConstantCompositeOpPattern final
         for (FloatAttr srcAttr : dstElementsAttr.getValues<FloatAttr>()) {
           Attribute dstAttr = nullptr;
           // Handle 8-bit float conversion to 8-bit integer.
-          if (srcElemType.getIntOrFloatBitWidth() == 8 &&
+          auto *typeConverter = getTypeConverter<SPIRVTypeConverter>();
+          if (typeConverter->getOptions().emulateUnsupportedFloatTypes &&
+              srcElemType.getIntOrFloatBitWidth() == 8 &&
               isa<IntegerType>(dstElemType)) {
             dstAttr =
                 getIntegerAttrFromFloatAttr(srcAttr, dstElemType, rewriter);
@@ -381,7 +383,9 @@ struct ConstantScalarOpPattern final
 
       // Floating-point types not supported in the target environment are all
       // converted to float type.
-      if (srcType.getIntOrFloatBitWidth() == 8 && isa<IntegerType>(dstType) &&
+      auto *typeConverter = getTypeConverter<SPIRVTypeConverter>();
+      if (typeConverter->getOptions().emulateUnsupportedFloatTypes &&
+          srcType.getIntOrFloatBitWidth() == 8 && isa<IntegerType>(dstType) &&
           dstType.getIntOrFloatBitWidth() == 8) {
         // If the source is an 8-bit float, convert it to a 8-bit integer.
         dstAttr = getIntegerAttrFromFloatAttr(srcAttr, dstType, rewriter);
@@ -1374,6 +1378,7 @@ struct ConvertArithToSPIRVPass
 
     SPIRVConversionOptions options;
     options.emulateLT32BitScalarTypes = this->emulateLT32BitScalarTypes;
+    options.emulateUnsupportedFloatTypes = this->emulateUnsupportedFloatTypes;
     SPIRVTypeConverter typeConverter(targetAttr, options);
 
     // Use UnrealizedConversionCast as the bridge so that we don't need to pull

mlir/lib/Dialect/SPIRV/Transforms/SPIRVConversion.cpp

@@ -345,12 +345,12 @@ static Type convert8BitFloatType(const SPIRVConversionOptions &options,
 
 /// Returns a type with the same shape but with any 8-bit float element type
 /// converted to the same bit width integer type. This is a noop when the
-/// element type is not the 8-bit float type.
+/// element type is not the 8-bit float type or emulation flag is set to false.
 static ShapedType
 convertShaped8BitFloatType(ShapedType type,
                            const SPIRVConversionOptions &options) {
   if (!options.emulateUnsupportedFloatTypes)
-    return nullptr;
+    return type;
   auto srcElementType = type.getElementType();
   Type convertedElementType = nullptr;
   // F8 types are converted to integer types with the same bit width.

mlir/test/Conversion/ArithToSPIRV/arith-to-spirv.mlir

@@ -559,6 +559,17 @@ func.func @constant() {
   return
 }
 
+// CHECK-LABEL: @constant_8bit_float
+func.func @constant_8bit_float() {
+  // CHECK: spirv.Constant 56 : i8
+  %cst = arith.constant 1.0 : f8E4M3
+  // CHECK: spirv.Constant dense<56> : vector<4xi8>
+  %cst_vector = arith.constant dense<1.0> : vector<4xf8E4M3>
+  // CHECK: spirv.Constant dense<60> : tensor<4xi8> : !spirv.array<4 x i8>
+  %cst_tensor = arith.constant dense<1.0> : tensor<4xf8E5M2>
+  return
+}
+
 // CHECK-LABEL: @constant_16bit
 func.func @constant_16bit() {
   // CHECK: spirv.Constant 4 : i16

mlir/test/Conversion/FuncToSPIRV/types-to-spirv.mlir

@@ -1,6 +1,8 @@
 // RUN: mlir-opt -split-input-file -convert-func-to-spirv %s -o - | FileCheck %s
 // RUN: mlir-opt -split-input-file -convert-func-to-spirv="emulate-lt-32-bit-scalar-types=false" %s | \
 // RUN:   FileCheck %s --check-prefix=NOEMU
+// RUN: mlir-opt -split-input-file -convert-func-to-spirv="emulate-unsupported-float-types=false" %s | \
+// RUN:   FileCheck %s --check-prefix=UNSUPPORTED_FLOAT
 
 //===----------------------------------------------------------------------===//
 // Integer types
@@ -944,3 +946,55 @@ func.func @unranked_tensor(%arg0: tensor<*xi32>) { return }
 func.func @dynamic_dim_tensor(%arg0: tensor<8x?xi32>) { return }
 
 } // end module
+
+
+// -----
+
+// Check that 8-bit float types are emulated as i8.
+module attributes {
+  spirv.target_env = #spirv.target_env<#spirv.vce<v1.0, [Int8], []>, #spirv.resource_limits<>>
+} {
+
+  // CHECK: spirv.func @float8_to_integer8
+  // CHECK-SAME: (%arg0: i8
+  // CHECK-SAME: %arg1: i8
+  // CHECK-SAME: %arg2: i8
+  // CHECK-SAME: %arg3: i8
+  // CHECK-SAME: %arg4: i8
+  // CHECK-SAME: %arg5: i8
+  // CHECK-SAME: %arg6: i8
+  // CHECK-SAME: %arg7: i8
+  // CHECK-SAME: %arg8: vector<4xi8>
+  // CHECK-SAME: %arg9: !spirv.ptr<!spirv.struct<(!spirv.array<8 x i8, stride=1> [0])>, StorageBuffer>
+  // CHECK-SAME: %arg10: !spirv.array<4 x i8>
+  // UNSUPPORTED_FLOAT-LABEL: func.func @float8_to_integer8
+  // UNSUPPORTED_FLOAT-SAME: (%arg0: f8E5M2
+  // UNSUPPORTED_FLOAT-SAME: %arg1: f8E4M3
+  // UNSUPPORTED_FLOAT-SAME: %arg2: f8E4M3FN
+  // UNSUPPORTED_FLOAT-SAME: %arg3: f8E5M2FNUZ
+  // UNSUPPORTED_FLOAT-SAME: %arg4: f8E4M3FNUZ
+  // UNSUPPORTED_FLOAT-SAME: %arg5: f8E4M3B11FNUZ
+  // UNSUPPORTED_FLOAT-SAME: %arg6: f8E3M4
+  // UNSUPPORTED_FLOAT-SAME: %arg7: f8E8M0FNU
+  // UNSUPPORTED_FLOAT-SAME: %arg8: vector<4xf8E4M3B11FNUZ>
+  // UNSUPPORTED_FLOAT-SAME: %arg9: memref<8xf8E4M3, #spirv.storage_class<StorageBuffer>>
+  // UNSUPPORTED_FLOAT-SAME: %arg10: tensor<4xf8E5M2>
+  // UNSUPPORTED_FLOAT-SAME: ) {
+
+  func.func @float8_to_integer8(
+    %arg0: f8E5M2,                   // CHECK-NOT: f8E5M2
+    %arg1: f8E4M3,                   // CHECK-NOT: f8E4M3
+    %arg2: f8E4M3FN,                // CHECK-NOT: f8E4M3FN
+    %arg3: f8E5M2FNUZ,              // CHECK-NOT: f8E5M2FNUZ
+    %arg4: f8E4M3FNUZ,              // CHECK-NOT: f8E4M3FNUZ
+    %arg5: f8E4M3B11FNUZ,           // CHECK-NOT: f8E4M3B11FNUZ
+    %arg6: f8E3M4,                  // CHECK-NOT: f8E3M4
+    %arg7: f8E8M0FNU,               // CHECK-NOT: f8E8M0FNU
+    %arg8: vector<4xf8E4M3B11FNUZ>, // CHECK-NOT: vector<4xf8E4M3B11FNUZ>
+    %arg9: memref<8xf8E4M3, #spirv.storage_class<StorageBuffer>>, // CHECK-NOT: memref
+    %arg10: tensor<4xf8E5M2>        // CHECK-NOT: tensor
+  ) {
+    // CHECK: spirv.Return
+    return
+  }
+}