[Mlir-commits] [mlir] [mlir][tosa][tosa-to-linalg] Add NaN Mode Lowering (PR #125668)

[Suraj Sudhir]

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@@ -36,6 +36,47 @@
 using namespace mlir;
 using namespace mlir::tosa;
 
+// Helper function to materialize the semantically correct compare and select
+// operations a binary operation with a specific NaN propagation mode.
+//
+// In the case of "PROPAGATE" semantics no compare and selection is required and
+// this function does nothing.
+//
+// In the case of "IGNORE" semantics this function materializes a comparison of
+// the current operands to the op which will return true for any NaN
+// argument and then selects between the non-NaN operation argument and the
+// calculated result based on whether the lhs or rhs is NaN or not. In pseudo
+// code:
+//
+// binary<op>(lhs, rhs):
+//   result = op(lhs, rhs)
+//   if lhs == NaN return rhs
+//   if rhs == NaN return lhs
+//   return result
+static Value materializeBinaryNanCheckIfRequired(Operation *op,
+                                                 PatternRewriter &rewriter,
+                                                 Value lhs, Value rhs,
+                                                 Value result) {
+  const auto nanMode = getNanMode(op, rewriter);
+  if (!nanMode)
+    return {};
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sjarus wrote:

Isn't the absence of the parameter equivalent to PROPAGATE generally ? Also, {} ought to return the default initialized value. Is that what makes sense to return rather than std::optional<Value> ? 

https://github.com/llvm/llvm-project/pull/125668