[Mlir-commits] [mlir] [mlir][Vector] add vector.insert canonicalization pattern for vectors created from ub.poison (PR #142944)

[Yang Bai]

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@@ -3191,6 +3227,114 @@ class InsertSplatToSplat final : public OpRewritePattern<InsertOp> {
   }
 };
 
+/// Pattern to optimize a chain of constant insertions into a poison vector.
+///
+/// This pattern identifies chains of vector.insert operations that:
+/// 1. Start from an ub.poison operation.
+/// 2. Insert only constant values at static positions.
+/// 3. Completely initialize all elements in the resulting vector.
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yangtetris wrote:

> It shouldn't matter at all if the start is a ub.poison.

After a second thought, I think it indeed makes sense. We don’t need to worry about whether a canonicalization pattern may overlap with a folder in some cases. I'll remove the check for `ub.poison`.

https://github.com/llvm/llvm-project/pull/142944