[llvm] [clang] [clang][llvm][fatlto] Avoid cloning modules in FatLTO (PR #72180)

[Paul Kirth via cfe-commits]

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@@ -810,7 +810,7 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
   // Only enable CGProfilePass when using integrated assembler, since
   // non-integrated assemblers don't recognize .cgprofile section.
   PTO.CallGraphProfile = !CodeGenOpts.DisableIntegratedAS;
-  PTO.UnifiedLTO = CodeGenOpts.UnifiedLTO;
+  PTO.UnifiedLTO = CodeGenOpts.UnifiedLTO || CodeGenOpts.FatLTO;
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ilovepi wrote:

Yeah, this is probably redundant since I made that change earlier in the driver. The assert is also a good suggestion, so I'll update this patch to do that too.

For the module flag, I'll need to check, since I think that it won't be set otherwise, but maybe I can factor it out into a common block.

https://github.com/llvm/llvm-project/pull/72180