[PATCH] D150505: [cmake] Disable GCC lifetime DSE

[Xi Ruoyao via Phabricator via llvm-commits]

xry111 added inline comments.


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Comment at: llvm/cmake/modules/HandleLLVMOptions.cmake:597
 
+if ( LLVM_COMPILER_IS_GCC_COMPATIBLE )
+  # LLVM data structures like llvm::User and llvm::MDNode rely on
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jhuber6 wrote:
> Maybe we could restrict this to `LLVM_ENABLE_LTO`?
No, generally we are invoking undefined behavior and generally we need to tell GCC not to consider it undefined.  LTO just exploited it.

During our field test `-flifetime-dse=1` is enough to cover up the issue, but we decided to "do things correctly" instead of just "make it work".


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D150505/new/

https://reviews.llvm.org/D150505