[clang] [CodeGen] Implement post-opt linking option for builtin bitocdes (PR #69371)

[Joseph Huber via cfe-commits]

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@@ -98,6 +100,11 @@ extern cl::opt<bool> PrintPipelinePasses;
 static cl::opt<bool> ClSanitizeOnOptimizerEarlyEP(
     "sanitizer-early-opt-ep", cl::Optional,
     cl::desc("Insert sanitizers on OptimizerEarlyEP."), cl::init(false));
+
+// Re-link builtin bitcodes after optimization
+static cl::opt<bool> ClRelinkBuiltinBitcodePostop(
+    "relink-builtin-bitcode-postop", cl::Optional,
+    cl::desc("Re-link builtin bitcodes after optimization."), cl::init(false));
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jhuber6 wrote:

That's a clang flag, this is presumably more of an LLVM one because this added a new pass that lives in Clang. I still think the solution to this was to just stop the backend from doing this optimization if it will obviously break it, but supposedly that caused performance regressions.

https://github.com/llvm/llvm-project/pull/69371