[PATCH] D150332: [SystemZ][z/OS] Save (and restore) R3 to avoid clobbering parameter when call stack frame extension is invoked

[Ulrich Weigand via Phabricator via llvm-commits]

uweigand added inline comments.


================
Comment at: llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp:1354
+          .addReg(SystemZ::R3D)
+          .addReg(SystemZ::R0D)
+          .addImm(SaveSlotR3)
----------------
%r0 cannot be used as base register.  Is this really supposed to store to the low core?  (On Linux, that might be unsafe as it could be clobbered if we're e.g. interrupted by an async signal handler - not sure if there are similar concerns on z/OS.)  If yes, you need to use `addReg(0)` here.   If no, I guess some other changes are required.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D150332/new/

https://reviews.llvm.org/D150332