Author: Juneyoung Lee Date: 2020-09-08T11:40:24+09:00 New Revision: e7e6335763cafe06988a6c06ed50af0b4ec28d8b
URL: https://github.com/llvm/llvm-project/commit/e7e6335763cafe06988a6c06ed50af0b4ec28d8b DIFF: https://github.com/llvm/llvm-project/commit/e7e6335763cafe06988a6c06ed50af0b4ec28d8b.diff LOG: ReleaseNotes: Add updates in LangRef related with undef/poison Added: Modified: llvm/docs/ReleaseNotes.rst Removed: ################################################################################ diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst index cbc8c0859c7b..0d5e0137bbc4 100644 --- a/llvm/docs/ReleaseNotes.rst +++ b/llvm/docs/ReleaseNotes.rst @@ -101,6 +101,18 @@ Changes to the LLVM IR where ``uint64_t`` was used to denote the size in bits of a IR type we have partially migrated the codebase to using ``llvm::TypeSize``. +* Branching on ``undef``/``poison`` is undefined behavior. It is needed for + correctly analyzing value ranges based on branch conditions. This is + consistent with MSan's behavior as well. + +* ``memset``/``memcpy``/``memmove`` can take ``undef``/``poison`` pointer(s) + if the size to fill is zero. + +* Passing ``undef``/``poison`` to a standard I/O library function call + (`printf`/`fputc`/...) is undefined behavior. The new ``noundef`` attribute + is attached to the functions' arguments. The full list is available at + ``llvm::inferLibFuncAttributes``. + Changes to building LLVM ------------------------ @@ -305,6 +317,10 @@ Changes to the Go bindings Changes to the DAG infrastructure --------------------------------- +* A SelDag-level freeze instruction has landed. It is simply lowered as a copy + operation to MachineIR, but to make it fully correct either IMPLICIT_DEF + should be fixed or the equivalent FREEZE operation should be added to + MachineIR. Changes to the Debug Info --------------------------------- _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
