[FXML-4281] Remove flag for rounding mode of casting ops

Author: cferry-AMD

mlir/include/mlir/Conversion/ArithToEmitC/ArithToEmitC.h

@@ -14,8 +14,7 @@ class RewritePatternSet;
 class TypeConverter;
 
 void populateArithToEmitCPatterns(TypeConverter &typeConverter,
-                                  RewritePatternSet &patterns,
-                                  bool optionFloatToIntTruncates);
+                                  RewritePatternSet &patterns);
 } // namespace mlir
 
 #endif // MLIR_CONVERSION_ARITHTOEMITC_ARITHTOEMITC_H

mlir/include/mlir/Conversion/Passes.td

@@ -139,24 +139,7 @@ def ArithToAMDGPUConversionPass : Pass<"convert-arith-to-amdgpu"> {
 
 def ConvertArithToEmitC : Pass<"convert-arith-to-emitc"> {
   let summary = "Convert Arith dialect to EmitC dialect";
-  let description = [{
-    This pass converts `arith` dialect operations to `emitc`.
-
-    The semantics of floating-point to integer conversions `arith.fptosi`, 
-    `arith.fptoui` require rounding towards zero. Typical C++ implementations
-    use this behavior for float-to-integer casts, but that is not mandated by 
-    C++ and there are implementation-defined means to change the default behavior.
-    
-    If casts can be guaranteed to use round-to-zero, use the 
-    `float-to-int-truncates` flag to allow conversion of `arith.fptosi` and
-    `arith.fptoui` operations.
-  }];
   let dependentDialects = ["emitc::EmitCDialect"];
-  let options = [
-    Option<"floatToIntTruncates", "float-to-int-truncates", "bool",
-           /*default=*/"false",
-           "Whether the behavior of float-to-int cast in emitc is truncation">,
-  ];
 }
 
 //===----------------------------------------------------------------------===//

mlir/lib/Conversion/ArithToEmitC/ArithToEmitC.cpp

@@ -366,14 +366,9 @@ class SelectOpConversion : public OpConversionPattern<arith::SelectOp> {
 // Floating-point to integer conversions.
 template <typename CastOp>
 class FtoICastOpConversion : public OpConversionPattern<CastOp> {
-private:
-  bool floatToIntTruncates;
-
 public:
-  FtoICastOpConversion(const TypeConverter &typeConverter, MLIRContext *context,
-                       bool optionFloatToIntTruncates)
-      : OpConversionPattern<CastOp>(typeConverter, context),
-        floatToIntTruncates(optionFloatToIntTruncates) {}
+  FtoICastOpConversion(const TypeConverter &typeConverter, MLIRContext *context)
+      : OpConversionPattern<CastOp>(typeConverter, context) {}
 
   LogicalResult
   matchAndRewrite(CastOp castOp, typename CastOp::Adaptor adaptor,
@@ -384,16 +379,13 @@ class FtoICastOpConversion : public OpConversionPattern<CastOp> {
       return rewriter.notifyMatchFailure(castOp,
                                          "unsupported cast source type");
 
-    if (!floatToIntTruncates)
-      return rewriter.notifyMatchFailure(
-          castOp, "conversion currently requires EmitC casts to use truncation "
-                  "as rounding mode");
-
     Type dstType = this->getTypeConverter()->convertType(castOp.getType());
     if (!dstType)
       return rewriter.notifyMatchFailure(castOp, "type conversion failed");
 
-    if (!emitc::isSupportedIntegerType(dstType))
+    // Float-to-i1 casts are not supported: any value with 0 < value < 1 must be
+    // truncated to 0, whereas a boolean conversion would return true.
+    if (!emitc::isSupportedIntegerType(dstType) || dstType.isInteger(1))
       return rewriter.notifyMatchFailure(castOp,
                                          "unsupported cast destination type");
 
@@ -468,8 +460,7 @@ class ItoFCastOpConversion : public OpConversionPattern<CastOp> {
 //===----------------------------------------------------------------------===//
 
 void mlir::populateArithToEmitCPatterns(TypeConverter &typeConverter,
-                                        RewritePatternSet &patterns,
-                                        bool optionFloatToIntTruncates) {
+                                        RewritePatternSet &patterns) {
   MLIRContext *ctx = patterns.getContext();
 
   // clang-format off
@@ -488,11 +479,9 @@ void mlir::populateArithToEmitCPatterns(TypeConverter &typeConverter,
     CmpIOpConversion,
     SelectOpConversion,
     ItoFCastOpConversion<arith::SIToFPOp>,
-    ItoFCastOpConversion<arith::UIToFPOp>
-  >(typeConverter, ctx)
-  .add<
+    ItoFCastOpConversion<arith::UIToFPOp>,
     FtoICastOpConversion<arith::FPToSIOp>,
     FtoICastOpConversion<arith::FPToUIOp>
-  >(typeConverter, ctx, optionFloatToIntTruncates);
+  >(typeConverter, ctx);
   // clang-format on
 }

mlir/lib/Conversion/ArithToEmitC/ArithToEmitCPass.cpp

@@ -45,7 +45,7 @@ void ConvertArithToEmitC::runOnOperation() {
   TypeConverter typeConverter;
   typeConverter.addConversion([](Type type) { return type; });
 
-  populateArithToEmitCPatterns(typeConverter, patterns, floatToIntTruncates);
+  populateArithToEmitCPatterns(typeConverter, patterns);
 
   if (failed(
           applyPartialConversion(getOperation(), target, std::move(patterns))))

mlir/test/Conversion/ArithToEmitC/arith-to-emitc-cast-truncate.mlir

@@ -16,8 +16,66 @@ func.func @arith_cmpf_vector(%arg0: vector<5xf32>, %arg1: vector<5xf32>) -> vect
 
 // -----
 
-func.func @arith_cast_f32(%arg0: f32) -> i32 {
+func.func @arith_cast_tensor(%arg0: tensor<5xf32>) -> tensor<5xi32> {
   // expected-error @+1 {{failed to legalize operation 'arith.fptosi'}}
-  %t = arith.fptosi %arg0 : f32 to i32
+  %t = arith.fptosi %arg0 : tensor<5xf32> to tensor<5xi32>
+  return %t: tensor<5xi32>
+}
+
+// -----
+
+func.func @arith_cast_vector(%arg0: vector<5xf32>) -> vector<5xi32> {
+  // expected-error @+1 {{failed to legalize operation 'arith.fptosi'}}
+  %t = arith.fptosi %arg0 : vector<5xf32> to vector<5xi32>
+  return %t: vector<5xi32>
+}
+
+// -----
+
+func.func @arith_cast_bf16(%arg0: bf16) -> i32 {
+  // expected-error @+1 {{failed to legalize operation 'arith.fptosi'}}
+  %t = arith.fptosi %arg0 : bf16 to i32
   return %t: i32
 }
+
+// -----
+
+func.func @arith_cast_f16(%arg0: f16) -> i32 {
+  // expected-error @+1 {{failed to legalize operation 'arith.fptosi'}}
+  %t = arith.fptosi %arg0 : f16 to i32
+  return %t: i32
+}
+
+
+// -----
+
+func.func @arith_cast_to_bf16(%arg0: i32) -> bf16 {
+  // expected-error @+1 {{failed to legalize operation 'arith.sitofp'}}
+  %t = arith.sitofp %arg0 : i32 to bf16
+  return %t: bf16
+}
+
+// -----
+
+func.func @arith_cast_to_f16(%arg0: i32) -> f16 {
+  // expected-error @+1 {{failed to legalize operation 'arith.sitofp'}}
+  %t = arith.sitofp %arg0 : i32 to f16
+  return %t: f16
+}
+
+// -----
+
+func.func @arith_cast_fptosi_i1(%arg0: f32) -> i1 {
+  // expected-error @+1 {{failed to legalize operation 'arith.fptosi'}}
+  %t = arith.fptosi %arg0 : f32 to i1
+  return %t: i1
+}
+
+// -----
+
+func.func @arith_cast_fptoui_i1(%arg0: f32) -> i1 {
+  // expected-error @+1 {{failed to legalize operation 'arith.fptoui'}}
+  %t = arith.fptoui %arg0 : f32 to i1
+  return %t: i1
+}
+

mlir/test/Conversion/ArithToEmitC/arith-to-emitc-cast-unsupported.mlir

@@ -309,22 +309,6 @@ func.func @arith_cmpf_true(%arg0: f32, %arg1: f32) -> i1 {
 
 // -----
 
-func.func @arith_int_to_float_cast_ops(%arg0: i8, %arg1: i64) {
-  // CHECK: emitc.cast %arg0 : i8 to f32
-  %0 = arith.sitofp %arg0 : i8 to f32
-
-  // CHECK: emitc.cast %arg1 : i64 to f32
-  %1 = arith.sitofp %arg1 : i64 to f32
-
-  // CHECK: %[[CAST_UNS:.*]] = emitc.cast %arg0 : i8 to ui8
-  // CHECK: emitc.cast %[[CAST_UNS]] : ui8 to f32
-  %2 = arith.uitofp %arg0 : i8 to f32
-
-  return
-}
-
-// -----
-
 func.func @arith_cmpi_eq(%arg0: i32, %arg1: i32) -> i1 {
   // CHECK-LABEL: arith_cmpi_eq
   // CHECK-SAME: ([[Arg0:[^ ]*]]: i32, [[Arg1:[^ ]*]]: i32)
@@ -370,3 +354,39 @@ func.func @arith_cmpi_predicates(%arg0: i32, %arg1: i32) {
 
   return
 }
+
+// -----
+
+func.func @arith_float_to_int_cast_ops(%arg0: f32, %arg1: f64) {
+  // CHECK: emitc.cast %arg0 : f32 to i32
+  %0 = arith.fptosi %arg0 : f32 to i32
+
+  // CHECK: emitc.cast %arg1 : f64 to i32
+  %1 = arith.fptosi %arg1 : f64 to i32
+
+  // CHECK: emitc.cast %arg0 : f32 to i16
+  %2 = arith.fptosi %arg0 : f32 to i16
+
+  // CHECK: emitc.cast %arg1 : f64 to i16
+  %3 = arith.fptosi %arg1 : f64 to i16
+
+  // CHECK: %[[CAST0:.*]] = emitc.cast %arg0 : f32 to ui32
+  // CHECK: emitc.cast %[[CAST0]] : ui32 to i32
+  %4 = arith.fptoui %arg0 : f32 to i32
+
+  return
+}
+
+func.func @arith_int_to_float_cast_ops(%arg0: i8, %arg1: i64) {
+  // CHECK: emitc.cast %arg0 : i8 to f32
+  %0 = arith.sitofp %arg0 : i8 to f32
+
+  // CHECK: emitc.cast %arg1 : i64 to f32
+  %1 = arith.sitofp %arg1 : i64 to f32
+
+  // CHECK: %[[CAST_UNS:.*]] = emitc.cast %arg0 : i8 to ui8
+  // CHECK: emitc.cast %[[CAST_UNS]] : ui8 to f32
+  %2 = arith.uitofp %arg0 : i8 to f32
+
+  return
+}