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

Sat May 13 23:12:59 PDT 2023

thesamesam added a comment.

I can only reproduce it with a GCC-built LLVM.

Anyway, given `LLVM_COMPILER_IS_GCC_COMPATIBLE` is true for Clang (see `llvm/cmake/modules/DetermineGCCCompatible.cmake`), it seems easiest for us to just check `CMAKE_COMPILER_IS_GNUCXX` instead (given Clang doesn't acknowledge `-fno-lifetime-dse` at all).

I'll test that now.

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Comment at: llvm/cmake/modules/HandleLLVMOptions.cmake:597-603
+if ( LLVM_COMPILER_IS_GCC_COMPATIBLE )
+  # LLVM data structures like llvm::User and llvm::MDNode rely on
+  # the value of object storage persisting beyond the lifetime of the
+  # object (#24952).  This is not standard compliant and causes a runtime
+  # crash if LLVM is built with GCC and LTO enabled (#57740).  Until
+  # these bugs are fixed, we need to disable dead store eliminations
+  # based on object lifetime.
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bi

Repository:
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  https://reviews.llvm.org/D150505/new/

https://reviews.llvm.org/D150505