[PATCH] D101010: [SystemZ] [z/OS] Add XPLINK64 Calling Convention to SystemZ

Thu Apr 22 10:49:58 PDT 2021

Everybody0523 added inline comments.

================
Comment at: llvm/lib/Target/SystemZ/SystemZCallingConv.td:165
 def CSR_SystemZ_XPLINK64 : CalleeSavedRegs<(add (sequence "R%dD", 8, 15),
-                                                (sequence "F%dD", 8, 15))>;
+                                                (sequence "F%dD", 15, 8))>;
+
----------------
uweigand wrote:
> Why are you changing the sequence here?  I didn't think the order of CSRs in that list should make any particular difference ...
The CSR mask is generated in order based on this list. However, FPRs are preserved in the save area in reverse order, which is contrary to the current CSR mask. The previous commit not reversing the order of the callee-saved FPRs was an oversight. 

With all that said and done, if you prefer I can keep the sequence unchanged for now and create a separate patch that fixes this bug. 

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D101010/new/

https://reviews.llvm.org/D101010