[PATCH] D18644: [SystemZ] Support ATOMIC_FENCE

[Bryan Chan via llvm-commits]

bryanpkc created this revision.
bryanpkc added a reviewer: uweigand.
bryanpkc added a subscriber: llvm-commits.

A call to the __sync_synchronize() built-in should be lowered into z/Architecture's BCR serialization instruction, instead of causing a fatal error in the back-end.

http://reviews.llvm.org/D18644

Files:
  lib/Target/SystemZ/SystemZISelLowering.cpp
  lib/Target/SystemZ/SystemZISelLowering.h
  test/CodeGen/SystemZ/atomic-fence.ll

Index: test/CodeGen/SystemZ/atomic-fence.ll
===================================================================
--- /dev/null
+++ test/CodeGen/SystemZ/atomic-fence.ll
@@ -0,0 +1,16 @@
+; Test (fast) serialization.
+;
+; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s --check-prefix=Z10
+; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z196  | FileCheck %s --check-prefix=Z196
+; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=zEC12 | FileCheck %s --check-prefix=ZEC12
+; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z13   | FileCheck %s --check-prefix=Z13
+
+define void @test() {
+; Z10:   bcr 15, %r0
+; Z196:  bcr 14, %r0
+; ZEC12: bcr 14, %r0
+; Z13:   bcr 14, %r0
+  fence seq_cst
+  ret void
+}
+
Index: lib/Target/SystemZ/SystemZISelLowering.h
===================================================================
--- lib/Target/SystemZ/SystemZISelLowering.h
+++ lib/Target/SystemZ/SystemZISelLowering.h
@@ -479,6 +479,7 @@
   SDValue lowerBITCAST(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerOR(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerCTPOP(SDValue Op, SelectionDAG &DAG) const;
+  SDValue lowerATOMIC_FENCE(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerATOMIC_LOAD(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerATOMIC_STORE(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerATOMIC_LOAD_OP(SDValue Op, SelectionDAG &DAG,
Index: lib/Target/SystemZ/SystemZISelLowering.cpp
===================================================================
--- lib/Target/SystemZ/SystemZISelLowering.cpp
+++ lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -216,6 +216,8 @@
   setOperationAction(ISD::ATOMIC_LOAD_UMAX, MVT::i32, Custom);
   setOperationAction(ISD::ATOMIC_CMP_SWAP,  MVT::i32, Custom);
 
+  setOperationAction(ISD::ATOMIC_FENCE, MVT::Other, Custom);
+
   // z10 has instructions for signed but not unsigned FP conversion.
   // Handle unsigned 32-bit types as signed 64-bit types.
   if (!Subtarget.hasFPExtension()) {
@@ -3118,6 +3120,12 @@
   return Op;
 }
 
+SDValue SystemZTargetLowering::lowerATOMIC_FENCE(SDValue Op,
+                                                 SelectionDAG &DAG) const {
+  SDLoc DL(Op);
+  return SDValue(DAG.getMachineNode(SystemZ::Serialize, DL, MVT::Other), 0);
+}
+
 // Op is an atomic load.  Lower it into a normal volatile load.
 SDValue SystemZTargetLowering::lowerATOMIC_LOAD(SDValue Op,
                                                 SelectionDAG &DAG) const {
@@ -4444,6 +4452,8 @@
   case ISD::CTTZ_ZERO_UNDEF:
     return DAG.getNode(ISD::CTTZ, SDLoc(Op),
                        Op.getValueType(), Op.getOperand(0));
+  case ISD::ATOMIC_FENCE:
+    return lowerATOMIC_FENCE(Op, DAG);
   case ISD::ATOMIC_SWAP:
     return lowerATOMIC_LOAD_OP(Op, DAG, SystemZISD::ATOMIC_SWAPW);
   case ISD::ATOMIC_STORE:


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