[clang] [llvm] Adding splitdouble HLSL function (PR #109331)

[Farzon Lotfi via cfe-commits]

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@@ -264,6 +265,31 @@ class OpLowerer {
     return lowerToBindAndAnnotateHandle(F);
   }
 
+  Error replaceSplitDoubleCallUsages(CallInst *Intrin, CallInst *Op) {
+    IRBuilder<> &IRB = OpBuilder.getIRB();
+
+    for (Use &U : make_early_inc_range(Intrin->uses())) {
+      if (auto *EVI = dyn_cast<ExtractValueInst>(U.getUser())) {
+
+        assert(EVI->getNumIndices() == 1 &&
+               "splitdouble result should be indexed individually.");
+        if (EVI->getNumIndices() != 1)
+          return make_error<StringError>(
+              "splitdouble result should be indexed individually.",
+              inconvertibleErrorCode());
+
+        unsigned int IndexVal = EVI->getIndices()[0];
+
+        auto *OpEVI = IRB.CreateExtractValue(Op, IndexVal);
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farzonl wrote:

Just going to repeat this comment the `CreateExtractValue` should happen in  CGBuiltins.

https://github.com/llvm/llvm-project/pull/109331