Add an "is_signed" attribute to the quant_ConstFakeQuant op

Some TensorFlow simulated quantize ops such as QuantizeAndDequantizeV2Op have
attribute for the sign of the quantization, so quant_ConstFakeQuant should be
able to represent it with the new attribute is added.

The method for converting these attributes to an QuantizedType is updated to
handle this new argument.

PiperOrigin-RevId: 258810290

2 files changed, 10 insertions, 4 deletions

diff --git a/mlir/lib/Dialect/QuantOps/Transforms/ConvertSimQuant.cpp b/mlir/lib/Dialect/QuantOps/Transforms/ConvertSimQuant.cpp
index 0c93146a232..32d8c8a81c1 100644
--- a/mlir/lib/Dialect/QuantOps/Transforms/ConvertSimQuant.cpp
+++ b/mlir/lib/Dialect/QuantOps/Transforms/ConvertSimQuant.cpp
@@ -70,7 +70,7 @@ public:
     UniformQuantizedType uniformElementType = fakeQuantAttrsToType(
         fqOp.getLoc(), fqOp.num_bits().getSExtValue(),
         fqOp.min().convertToFloat(), fqOp.max().convertToFloat(),
-        fqOp.narrow_range(), converter.expressedType);
+        fqOp.narrow_range(), converter.expressedType, fqOp.is_signed());
 
     if (!uniformElementType) {
       // Note that the fakeQuantAttrsToType will have emitted the error.
diff --git a/mlir/lib/Dialect/QuantOps/Utils/FakeQuantSupport.cpp b/mlir/lib/Dialect/QuantOps/Utils/FakeQuantSupport.cpp
index 13c622e50d1..2667da98242 100644
--- a/mlir/lib/Dialect/QuantOps/Utils/FakeQuantSupport.cpp
+++ b/mlir/lib/Dialect/QuantOps/Utils/FakeQuantSupport.cpp
@@ -45,9 +45,15 @@ mlir::quant::fakeQuantAttrsToType(Location loc, unsigned numBits, double rmin,
     }
   } else if (numBits <= 16) {
     storageType = IntegerType::get(16, ctx);
-    flags = QuantizationFlags::Signed;
-    qmin = -32768;
-    qmax = 32767;
+    if (isSigned) {
+      flags = QuantizationFlags::Signed;
+      qmin = -32768;
+      qmax = 32767;
+    } else {
+      flags = 0;
+      qmin = 0;
+      qmax = 65535;
+    }
   } else {
     emitError(loc, "unsupported FakeQuant number of bits: ") << numBits;
     return nullptr;