[TORCH] Add f8 support in getConstantWithGivenDtypeAndValue utility (#4148)

Fixes iree-org/iree#20570.

---------

Signed-off-by: Vivek Khandelwal <vivekkhandelwal1424@gmail.com>

Author: vivekkhandelwal1

lib/Dialect/Torch/Utils/Utils.cpp

@@ -338,7 +338,9 @@ Value Torch::getConstantWithGivenDtypeAndValue(PatternRewriter &rewriter,
       dtype.isInteger(8) || dtype.isInteger(1))
     return rewriter.create<ConstantIntOp>(
         loc, rewriter.getI64IntegerAttr((int64_t)value));
-  if (dtype.isF64() || dtype.isF32() || dtype.isF16() || dtype.isBF16())
+  if (dtype.isF64() || dtype.isF32() || dtype.isF16() || dtype.isBF16() ||
+      isa<Float8E5M2Type, Float8E4M3FNType, Float8E5M2FNUZType,
+          Float8E4M3FNUZType>(dtype))
     return rewriter.create<ConstantFloatOp>(loc,
                                             rewriter.getF64FloatAttr(value));
   llvm::report_fatal_error(

test/Dialect/Torch/torch-function-to-torch-backend-pipeline.mlir

@@ -25,3 +25,13 @@ func.func @torch.uint8(%arg0: !torch.tensor {torch.type_bound = !torch.vtensor<[
   %1 = torch.aten.reshape %arg0, %0 : !torch.tensor, !torch.list<int> -> !torch.tensor
   return %1 : !torch.tensor
 }
+
+// CHECK-LABEL: func.func @torch.f8type
+func.func @torch.f8type(%arg0: !torch.vtensor<[5,3],f8E4M3FNUZ>) -> !torch.vtensor<[5,3],f8E4M3FNUZ> {
+  // CHECK: torch.aten.exp
+  // CHECK: torch.aten.log1p
+  // CHECK: torch.aten.tanh
+  // CHECK-SAME: !torch.vtensor<[5,3],f8E4M3FNUZ>
+  %0 = torch.aten.mish %arg0 : !torch.vtensor<[5,3],f8E4M3FNUZ> -> !torch.vtensor<[5,3],f8E4M3FNUZ>
+  return %0 : !torch.vtensor<[5,3],f8E4M3FNUZ>
+}