[SystemZ] Add support for sibling calls

This first cut is pretty conservative.  The final argument register (R6)
is call-saved, so we would need to make sure that the R6 argument to a
sibling call is the same as the R6 argument to the calling function,
which seems worth keeping as a separate patch.

Saying that integer truncations are free means that we no longer
use the extending instructions LGF and LLGF for spills in int-conv-09.ll
and int-conv-10.ll.  Instead we treat the registers as 64 bits wide and
truncate them to 32-bits where necessary.  I think it's unlikely we'd
use LGF and LLGF for spills in other situations for the same reason,
so I'm removing the tests rather than replacing them.  The associated
code is generic and applies to many more instructions than just
LGF and LLGF, so there is no corresponding code removal.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188669 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 0 deletions

diff --git a/lib/Target/SystemZ/SystemZOperators.td b/lib/Target/SystemZ/SystemZOperators.td
index 1a3d45e..8d6c619 100644
--- a/lib/Target/SystemZ/SystemZOperators.td
+++ b/lib/Target/SystemZ/SystemZOperators.td
@@ -82,6 +82,9 @@ def z_retflag           : SDNode<"SystemZISD::RET_FLAG", SDTNone,
 def z_call              : SDNode<"SystemZISD::CALL", SDT_ZCall,
                                  [SDNPHasChain, SDNPOutGlue, SDNPOptInGlue,
                                   SDNPVariadic]>;
+def z_sibcall           : SDNode<"SystemZISD::SIBCALL", SDT_ZCall,
+                                 [SDNPHasChain, SDNPOutGlue, SDNPOptInGlue,
+                                  SDNPVariadic]>;
 def z_pcrel_wrapper     : SDNode<"SystemZISD::PCREL_WRAPPER", SDT_ZWrapPtr, []>;
 def z_cmp               : SDNode<"SystemZISD::CMP", SDT_ZCmp, [SDNPOutGlue]>;
 def z_ucmp              : SDNode<"SystemZISD::UCMP", SDT_ZCmp, [SDNPOutGlue]>;