Early exit with rounding mode

Author: jacquesguan

mlir/lib/Conversion/ArithToEmitC/ArithToEmitC.cpp

@@ -748,6 +748,12 @@ class FpCastOpConversion : public OpConversionPattern<CastOp> {
     if (!emitc::isSupportedFloatType(operandType))
       return rewriter.notifyMatchFailure(castOp,
                                          "unsupported cast source type");
+    if (auto roundingModeOp =
+            dyn_cast<arith::ArithRoundingModeInterface>(*castOp)) {
+      // Only supporting default rounding mode as of now.
+      if (roundingModeOp.getRoundingModeAttr())
+        return rewriter.notifyMatchFailure(castOp, "unsupported rounding mode");
+    }
 
     Type dstType = this->getTypeConverter()->convertType(castOp.getType());
     if (!dstType)

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

@@ -149,3 +149,11 @@ func.func @arith_remui_vector(%arg0: vector<5xi32>, %arg1: vector<5xi32>) -> vec
   %divui = arith.remui %arg0, %arg1 : vector<5xi32>
   return %divui: vector<5xi32>
 }
+
+// -----
+
+func.func @arith_truncf(%arg0: f64) -> f32 {
+  // expected-error @+1 {{failed to legalize operation 'arith.truncf'}}
+  %truncd = arith.truncf %arg0 to_nearest_away : f64 to f32
+  return %truncd : f32
+}

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

@@ -764,4 +764,4 @@ func.func @arith_truncf(%arg0: f64) -> f16 {
   %truncd1 = arith.truncf %truncd0 : f32 to f16
 
   return %truncd1 : f16
-}
+}