[Mlir-commits] [mlir] [mlir][Vector] Add constant folding for vector.from_elements operation (PR #145849)

[Yang Bai]

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@@ -2459,8 +2459,30 @@ static OpFoldResult foldFromElementsToElements(FromElementsOp fromElementsOp) {
   return {};
 }
 
+/// Fold vector.from_elements to a constant when all operands are constants.
+/// Example:
+///   %c1 = arith.constant 1 : i32
+///   %c2 = arith.constant 2 : i32
+///   %v = vector.from_elements %c1, %c2 : vector<2xi32>
+/// =>
+///   %v = arith.constant dense<[1, 2]> : vector<2xi32>
+///
+static OpFoldResult foldFromElementsToConstant(FromElementsOp fromElementsOp,
+                                               ArrayRef<Attribute> elements) {
+  if (llvm::any_of(elements, [](Attribute attr) { return !attr; }))
+    return {};
+
+  auto destType = cast<VectorType>(fromElementsOp.getType());
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yangtetris wrote:

Cool, learned! I'll use getDest to replace the cast.

https://github.com/llvm/llvm-project/pull/145849