[mlir] [mlir][linalg] Support subtracting accumulation in partial reduction … (PR #214033)

[Andrzej Warzyński]

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@@ -534,6 +534,36 @@ static InitSliceInfo getInitSliceInfo(MLIRContext *context,
       partialReductionMap, initOperandShape);
 }
 
+/// Returns true if `combinerOp` accumulates into `accumulator` by subtracting
+/// the reduced value from it, i.e. it reduces the negated inputs.
+///
+/// Subtraction is not commutative, so this is a reduction only when the
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banach-space wrote:

What is "this" in this comment? The function merely consumes `combinerOp` and accumlator.

https://github.com/llvm/llvm-project/pull/214033