implement backend lowering for cksm instruction

llvm/include/llvm/IR/IntrinsicsSystemZ.td

@@ -462,3 +462,9 @@ let TargetPrefix = "s390" in {
   def int_s390_tdc : Intrinsic<[llvm_i32_ty], [llvm_anyfloat_ty, llvm_i64_ty],
                                [IntrNoMem]>;
 }
+
+let TargetPrefix = "s390" in {
+  def int_s390_cksm : Intrinsic<[llvm_i32_ty, llvm_ptr_ty, llvm_i64_ty],
+                                [llvm_i32_ty],
+                                [IntrReadMem]>;
+}

llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp

@@ -362,6 +362,18 @@ void SystemZAsmPrinter::emitInstruction(const MachineInstr *MI) {
 
     return;
   }
+  case SystemZ::CKSMLoop: {
+    MCSymbol *DotSym = OutContext.createTempSymbol();
+    OutStreamer->emitLabel(DotSym);
+    EmitToStreamer(*OutStreamer, MCInstBuilder(SystemZ::CKSM))
+                                    .addReg(MI->getOperand(1).getReg()
+                                    .addReg(MI->getOperand(2).getReg()));
+    // Emit jo to label
+    LoweredMI = MCInstBuilder(SystemZ::BRC)
+                    .addImm(MI->getOperand(0).getImm())
+                    .addImm(MI->getOperand(1).getImm())
+                    .addExpr(MCSymbolRefExpr::create(DotSym, Outcontext));
+  } break;
   case SystemZ::CallBRASL:
     LoweredMI = MCInstBuilder(SystemZ::BRASL)
       .addReg(SystemZ::R14D)

llvm/lib/Target/SystemZ/SystemZISelLowering.h

@@ -295,6 +295,14 @@ enum NodeType : unsigned {
   // Operand 1: the bit mask
   TDC,
 
+  // CheckSum Class
+  //
+  // Operand 0: output checksum 
+  // Operand 1: input checksum
+  // Operand 2: memory of buffer
+  // Operand 3: length
+  CKSM,
+
   // z/OS XPLINK ADA Entry
   // Wraps a TargetGlobalAddress that should be loaded from a function's
   // AssociatedData Area (ADA). Tha ADA is passed to the function by the

llvm/lib/Target/SystemZ/SystemZInstrInfo.td

@@ -2103,7 +2103,14 @@ let mayLoad = 1, mayStore = 1, Defs = [CC, R0D, R1D, R2D, R3D, R5D],
 
 // Checksum.
 let mayLoad = 1, Defs = [CC] in
-  def CKSM : SideEffectBinaryMemMemRRE<"cksm", 0xB241, GR64, GR128>;
+  def CKSM : SideEffectBinaryMemMemRRE<"cksm", 0xB241, GR32, GR128>;
+
+let usesCustomInserter = 1, mayLoad = 1, hasNoSchedulingInfo = 1, Defs = [CC] in
+  def CKSMLoop : Pseudo<(outs GR32:$cksmout),
+                        (ins GR32:cksmin, GR128:$ptr_len)>;
+  // Look for intrinsic and replace with pseudo instruction
+  def Pat<(int_s390_cksm GR32:$cksmin, ADDR64:$ptr, GR64:$len),
+          (CKSMLoop GR32:$cksmin, PAIR128(ADDR64:$ptr, GR64:$len))>
 
 // Compression call.
 let mayLoad = 1, mayStore = 1, Defs = [CC, R1D], Uses = [R0L, R1D] in

llvm/lib/Target/SystemZ/SystemZOperators.td

@@ -237,6 +237,11 @@ def SDT_ZVecQuaternaryIntCC : SDTypeProfile<2, 4,
 def SDT_ZTest               : SDTypeProfile<1, 2,
                                             [SDTCisVT<0, i32>,
                                              SDTCisVT<2, i64>]>;
+def SDT_ZCKSM               : SDTypeProfile<1, 3,
+                                            [SDTCisInt<0>,
+                                             SDTCisInt<1>,
+                                             SDTCisPtrTy<2>,
+                                             SDTCisInt<3>]>;
 
 //===----------------------------------------------------------------------===//
 // Node definitions
@@ -314,6 +319,9 @@ def z_stckf            : SDNode<"SystemZISD::STCKF", SDT_ZStoreInherent,
 
 def z_tdc               : SDNode<"SystemZISD::TDC", SDT_ZTest>;
 
+def z_cksm              : SDNode<"SystemZISD::CKSM", SDT_ZCKSM,
+                                 [SDNPHasChain, SDNMayLoad]>
+
 // Defined because the index is an i32 rather than a pointer.
 def z_vector_insert     : SDNode<"ISD::INSERT_VECTOR_ELT",
                                  SDT_ZInsertVectorElt>;

llvm/test/CodeGen/SystemZ/cksm-intrinsic-01.ll

@@ -0,0 +1,6 @@
+; RUN llc < %s -mtriple=s390x-ibm-zos -mcpu=z10 --stop-after=systemz-isel | FileCheck %s
+
+define i32 @get_checksum(i32 %cksmin, ptr %mem, i64 %len) {
+    %res = call i32 @llvm.s390.cksm(i32 %cksmin, ptr %mem, i64 %len)
+    ret i32 %res
+}