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

[Kunwar Grover]

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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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Groverkss wrote:

It shouldn't matter at all if the start is a ub.poison. If you think that the pattern isn't a canonicalization if the start is something else, then it shouldn't be a canonicalization at all. Personally, this seems like a cleanup and we could live with this in cleanup before lowering to backends.

But the initial start shouldn't matter at all whatever the case.

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