llvm-project

fb7a6d1c - [RISCV] Dynamically find unused register for stack protection code (#210992)

[RISCV] Dynamically find unused register for stack protection code (#210992) Previously stack protection used hardcoded registers which could conflict with registers being used by user code. This fixes a bug where clang -fstack-clash-protection would cause local variables to be trashed by the stack probing loop. The implementation is following the pattern of the AArch64 and X86 backends. Utility function getLiveRegsForEntryMBB has been copied from AArch64FrameLowering.cpp and findScratchNonCalleeSaveRegister is loosely based on the AArch64 version. This fixes Github issue #198699