[Mlir-commits] [mlir] [mlir][scf] Align `scf.while` `before` block args in canonicalizer (PR #76195)

[Matthias Springer]

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@@ -3872,14 +3872,89 @@ struct WhileRemoveDuplicatedResults : public OpRewritePattern<WhileOp> {
     return success();
   }
 };
+
+/// If both ranges contain same values return mappping indices from args1 to
+/// args2. Otherwise return std::nullopt
+static std::optional<SmallVector<unsigned>> getArgsMapping(ValueRange args1,
+                                                           ValueRange args2) {
+  if (args1.size() != args2.size())
+    return std::nullopt;
+
+  SmallVector<unsigned> ret(args1.size());
+  for (auto &&[i, arg1] : llvm::enumerate(args1)) {
+    auto it = llvm::find(args2, arg1);
+    if (it == args2.end())
+      return std::nullopt;
+
+    auto j = it - args2.begin();
+    ret[j] = static_cast<unsigned>(i);
+  }
+
+  return ret;
+}
+
+/// If `before` block args are directly forwarded to `scf.condition`, rearrange
+/// `scf.condition` args into same order as block args. Update `after` block
+// args and results values accordingly.
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matthias-springer wrote:

`result values`, a `/` is missing

https://github.com/llvm/llvm-project/pull/76195