[llvm] [TableGen] Split DAGISelMatcherOpt FactorNodes into 2 functions. NFC (PR #125330)

[Craig Topper via llvm-commits]

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@@ -492,6 +480,20 @@ static void FactorNodes(std::unique_ptr<Matcher> &InputMatcherPtr) {
     Scope->resetChild(i, OptionsToMatch[i]);
 }
 
+/// Search a ScopeMatcher to factor with FactorScope.
+static void FactorNodes(std::unique_ptr<Matcher> &InputMatcherPtr) {
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topperc wrote:

The code change the contents of the unique_ptr by calling unique_ptr::reset in several places. It replaces the ScopeMatcher with a SwitchOpcodeMatcher/SwitchType matcher by changing what the owner of ScopeMatcher is pointing to. This requires being able to modify the unique_ptr inside the owner.

https://github.com/llvm/llvm-project/pull/125330