Mark X86::RET and RETI instructions as variadic.

There is special magic happening when returning floating point values on
the x87 stack. The RET instructions get extra f80 operands.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162592 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86InstrControl.td b/lib/Target/X86/X86InstrControl.td
index b0c27c8..bfe9541 100644
--- a/lib/Target/X86/X86InstrControl.td
+++ b/lib/Target/X86/X86InstrControl.td
@@ -16,15 +16,18 @@
 //
 
 // Return instructions.
+//
+// The X86retflag return instructions are variadic because we may add ST0 and
+// ST1 arguments when returning values on the x87 stack.
 let isTerminator = 1, isReturn = 1, isBarrier = 1,
     hasCtrlDep = 1, FPForm = SpecialFP in {
-  def RET    : I   <0xC3, RawFrm, (outs), (ins),
+  def RET    : I   <0xC3, RawFrm, (outs), (ins variable_ops),
                     "ret",
                     [(X86retflag 0)], IIC_RET>;
   def RETW   : I   <0xC3, RawFrm, (outs), (ins),
                     "ret{w}",
                     [], IIC_RET>, OpSize;
-  def RETI   : Ii16<0xC2, RawFrm, (outs), (ins i16imm:$amt),
+  def RETI   : Ii16<0xC2, RawFrm, (outs), (ins i16imm:$amt, variable_ops),
                     "ret\t$amt",
                     [(X86retflag timm:$amt)], IIC_RET_IMM>;
   def RETIW  : Ii16<0xC2, RawFrm, (outs), (ins i16imm:$amt),