[clang] [Clang] Track alloca element types to avoid getAllocatedType() calls (PR #181740)

[Oliver Hunt via cfe-commits]

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@@ -119,7 +119,17 @@ enum TypeEvaluationKind {
 /// Helper class with most of the code for saving a value for a
 /// conditional expression cleanup.
 struct DominatingLLVMValue {
-  typedef llvm::PointerIntPair<llvm::Value *, 1, bool> saved_type;
+  struct saved_type {
+    llvm::Value *Value; // Original value if not saved, alloca if saved
+    llvm::Type *Type;   // nullptr if not saved, element type if saved
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ojhunt wrote:

This seems like it would have a significant impact on memory use based on the use in dominating sets - @mizvekov I'm not sufficiently familiar with this level of codegen, is this something you know? or know who would?

https://github.com/llvm/llvm-project/pull/181740