[Mlir-commits] [mlir] [mlir][VectorOps] Add fold `ExtractOp(CreateMask) -> CreateMask` (PR #69456)

[Benjamin Maxwell]

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@@ -100,6 +100,20 @@ static MaskFormat getMaskFormat(Value mask) {
       return MaskFormat::AllTrue;
     if (allFalse)
       return MaskFormat::AllFalse;
+  } else if (auto m = mask.getDefiningOp<CreateMaskOp>()) {
+    // Finds all-false create_masks. An all-true create_mask requires all
+    // dims to be constants, so that'll be folded to a constant_mask, then
+    // detected in the constant_mask case.
+    auto maskOperands = m.getOperands();
+    for (Value operand : maskOperands) {
+      if (auto constantOp = operand.getDefiningOp<arith::ConstantOp>()) {
+        int64_t dimSize =
+            llvm::cast<IntegerAttr>(constantOp.getValue()).getInt();
+        if (dimSize <= 0)
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MacDue wrote:

I don't think so, the docs say:
> If operand-value is negative, it is treated as if it were zero

https://github.com/llvm/llvm-project/pull/69456