[SDAG] Introduce a common MEMBARRIER node [nfc]

We have multiple targets which have defined custom instructions and sdag nodes to represent a compiler memory barrier. This patch consolidates the sdag node definition into common code.

This is a companion to D92842, but a bit different in focus. This change consolidates the existing sdag node definitions; that patch skipped defining a sdag node by instead going straight to a target node. That patch is also not NFC - as being so is quite hard for commoning up the instruction definitions.

I started with two backends to ensure the new common code was reusable while not having a massive diff. Once this lands, I'll submit a series of NFCs for backends where the changes are obvious, or reviews if more discussion is needed.

Differential Revision: https://reviews.llvm.org/D141317

diff --git a/llvm/include/llvm/CodeGen/ISDOpcodes.h b/llvm/include/llvm/CodeGen/ISDOpcodes.h
index 0a02a2c..f5e5437 100644 (file)
--- a/llvm/include/llvm/CodeGen/ISDOpcodes.h
+++ b/llvm/include/llvm/CodeGen/ISDOpcodes.h
@@ -1148,6 +1148,9 @@ enum NodeType {
   /// operand and output are the same floating type.
   ARITH_FENCE,
 
+  /// MEMBARRIER - Compiler barrier only; generate a no-op.
+  MEMBARRIER,
+
   /// OUTCHAIN = ATOMIC_FENCE(INCHAIN, ordering, scope)
   /// This corresponds to the fence instruction. It takes an input chain, and
   /// two integer constants: an AtomicOrdering and a SynchronizationScope.

diff --git a/llvm/include/llvm/Target/TargetSelectionDAG.td b/llvm/include/llvm/Target/TargetSelectionDAG.td
index c1b6ba4..8fead8e 100644 (file)
--- a/llvm/include/llvm/Target/TargetSelectionDAG.td
+++ b/llvm/include/llvm/Target/TargetSelectionDAG.td
@@ -291,10 +291,6 @@ def SDTPrefetch : SDTypeProfile<0, 4, [     // prefetch
   SDTCisPtrTy<0>, SDTCisSameAs<1, 2>, SDTCisSameAs<1, 3>, SDTCisInt<1>
 ]>;
 
-def SDTMemBarrier : SDTypeProfile<0, 5, [   // memory barrier
-  SDTCisSameAs<0,1>,  SDTCisSameAs<0,2>,  SDTCisSameAs<0,3>, SDTCisSameAs<0,4>,
-  SDTCisInt<0>
-]>;
 def SDTAtomicFence : SDTypeProfile<0, 2, [
   SDTCisSameAs<0,1>, SDTCisPtrTy<0>
 ]>;
@@ -631,6 +627,9 @@ def prefetch   : SDNode<"ISD::PREFETCH"   , SDTPrefetch,
 def readcyclecounter : SDNode<"ISD::READCYCLECOUNTER", SDTIntLeaf,
                      [SDNPHasChain, SDNPSideEffect]>;
 
+def membarrier : SDNode<"ISD::MEMBARRIER", SDTNone,
+                        [SDNPHasChain,SDNPSideEffect]>;
+
 def atomic_fence : SDNode<"ISD::ATOMIC_FENCE" , SDTAtomicFence,
                           [SDNPHasChain, SDNPSideEffect]>;
 

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
index 1561175..85b20af 100644 (file)
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
@@ -79,6 +79,7 @@ std::string SDNode::getOperationName(const SelectionDAG *G) const {
   case ISD::DELETED_NODE:               return "<<Deleted Node!>>";
 #endif
   case ISD::PREFETCH:                   return "Prefetch";
+  case ISD::MEMBARRIER:                 return "MemBarrier";
   case ISD::ATOMIC_FENCE:               return "AtomicFence";
   case ISD::ATOMIC_CMP_SWAP:            return "AtomicCmpSwap";
   case ISD::ATOMIC_CMP_SWAP_WITH_SUCCESS: return "AtomicCmpSwapWithSuccess";

diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
index 7345e03..2d2eb70 100644 (file)
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -4146,7 +4146,7 @@ SDValue SystemZTargetLowering::lowerATOMIC_FENCE(SDValue Op,
   }
 
   // MEMBARRIER is a compiler barrier; it codegens to a no-op.
-  return DAG.getNode(SystemZISD::MEMBARRIER, DL, MVT::Other, Op.getOperand(0));
+  return DAG.getNode(ISD::MEMBARRIER, DL, MVT::Other, Op.getOperand(0));
 }
 
 // Op is an atomic load.  Lower it into a normal volatile load.
@@ -5944,7 +5944,6 @@ const char *SystemZTargetLowering::getTargetNodeName(unsigned Opcode) const {
     OPCODE(STRCMP);
     OPCODE(SEARCH_STRING);
     OPCODE(IPM);
-    OPCODE(MEMBARRIER);
     OPCODE(TBEGIN);
     OPCODE(TBEGIN_NOFLOAT);
     OPCODE(TEND);

diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.h b/llvm/lib/Target/SystemZ/SystemZISelLowering.h
index 2ab9cb7..01ff246 100644 (file)
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.h
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.h
@@ -146,9 +146,6 @@ enum NodeType : unsigned {
   // Store the CC value in bits 29 and 28 of an integer.
   IPM,
 
-  // Compiler barrier only; generate a no-op.
-  MEMBARRIER,
-
   // Transaction begin.  The first operand is the chain, the second
   // the TDB pointer, and the third the immediate control field.
   // Returns CC value and chain.

diff --git a/llvm/lib/Target/SystemZ/SystemZInstrInfo.td b/llvm/lib/Target/SystemZ/SystemZInstrInfo.td
index ed7e3c0..59b3d54 100644 (file)
--- a/llvm/lib/Target/SystemZ/SystemZInstrInfo.td
+++ b/llvm/lib/Target/SystemZ/SystemZInstrInfo.td
@@ -1718,7 +1718,7 @@ def Serialize : Alias<2, (outs), (ins), []>;
 
 // A pseudo instruction that serves as a compiler barrier.
 let hasSideEffects = 1, hasNoSchedulingInfo = 1 in
-def MemBarrier : Pseudo<(outs), (ins), [(z_membarrier)]>;
+def MemBarrier : Pseudo<(outs), (ins), [(membarrier)]>;
 
 let Predicates = [FeatureInterlockedAccess1], Defs = [CC] in {
   def LAA   : LoadAndOpRSY<"laa",   0xEBF8, atomic_load_add_32, GR32>;

diff --git a/llvm/lib/Target/SystemZ/SystemZOperators.td b/llvm/lib/Target/SystemZ/SystemZOperators.td
index 9935416..4091c49 100644 (file)
--- a/llvm/lib/Target/SystemZ/SystemZOperators.td
+++ b/llvm/lib/Target/SystemZ/SystemZOperators.td
@@ -279,9 +279,6 @@ def z_usubo             : SDNode<"SystemZISD::USUBO", SDT_ZBinaryWithFlags>;
 def z_addcarry_1        : SDNode<"SystemZISD::ADDCARRY", SDT_ZBinaryWithCarry>;
 def z_subcarry_1        : SDNode<"SystemZISD::SUBCARRY", SDT_ZBinaryWithCarry>;
 
-def z_membarrier        : SDNode<"SystemZISD::MEMBARRIER", SDTNone,
-                                 [SDNPHasChain, SDNPSideEffect]>;
-
 def z_loadbswap        : SDNode<"SystemZISD::LRV", SDTLoad,
                                  [SDNPHasChain, SDNPMayLoad, SDNPMemOperand]>;
 def z_storebswap       : SDNode<"SystemZISD::STRV", SDTStore,

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 6fa6a86..58d8da1 100644 (file)
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -31661,7 +31661,7 @@ X86TargetLowering::lowerIdempotentRMWIntoFencedLoad(AtomicRMWInst *AI) const {
   // rmw. In practice, they do not look useful, so we don't try to be
   // especially clever.
   if (SSID == SyncScope::SingleThread)
-    // FIXME: we could just insert an X86ISD::MEMBARRIER here, except we are at
+    // FIXME: we could just insert an ISD::MEMBARRIER here, except we are at
     // the IR level, so we must wrap it in an intrinsic.
     return nullptr;
 
@@ -31782,7 +31782,7 @@ static SDValue LowerATOMIC_FENCE(SDValue Op, const X86Subtarget &Subtarget,
   }
 
   // MEMBARRIER is a compiler barrier; it codegens to a no-op.
-  return DAG.getNode(X86ISD::MEMBARRIER, dl, MVT::Other, Op.getOperand(0));
+  return DAG.getNode(ISD::MEMBARRIER, dl, MVT::Other, Op.getOperand(0));
 }
 
 static SDValue LowerCMP_SWAP(SDValue Op, const X86Subtarget &Subtarget,
@@ -32331,7 +32331,7 @@ static SDValue lowerAtomicArith(SDValue N, SelectionDAG &DAG,
                          DAG.getUNDEF(VT), NewChain);
     }
     // MEMBARRIER is a compiler barrier; it codegens to a no-op.
-    SDValue NewChain = DAG.getNode(X86ISD::MEMBARRIER, DL, MVT::Other, Chain);
+    SDValue NewChain = DAG.getNode(ISD::MEMBARRIER, DL, MVT::Other, Chain);
     assert(!N->hasAnyUseOfValue(0));
     // NOTE: The getUNDEF is needed to give something for the unused result 0.
     return DAG.getNode(ISD::MERGE_VALUES, DL, N->getVTList(),
@@ -34341,7 +34341,6 @@ const char *X86TargetLowering::getTargetNodeName(unsigned Opcode) const {
   NODE_NAME_CASE(VAARG_64)
   NODE_NAME_CASE(VAARG_X32)
   NODE_NAME_CASE(DYN_ALLOCA)
-  NODE_NAME_CASE(MEMBARRIER)
   NODE_NAME_CASE(MFENCE)
   NODE_NAME_CASE(SEG_ALLOCA)
   NODE_NAME_CASE(PROBED_ALLOCA)

diff --git a/llvm/lib/Target/X86/X86ISelLowering.h b/llvm/lib/Target/X86/X86ISelLowering.h
index 5268ee7..774d750 100644 (file)
--- a/llvm/lib/Target/X86/X86ISelLowering.h
+++ b/llvm/lib/Target/X86/X86ISelLowering.h
@@ -667,7 +667,6 @@ namespace llvm {
     PROBED_ALLOCA,
 
     // Memory barriers.
-    MEMBARRIER,
     MFENCE,
 
     // Get a random integer and indicate whether it is valid in CF.

diff --git a/llvm/lib/Target/X86/X86InstrCompiler.td b/llvm/lib/Target/X86/X86InstrCompiler.td
index 0ccf236..44a77a4 100644 (file)
--- a/llvm/lib/Target/X86/X86InstrCompiler.td
+++ b/llvm/lib/Target/X86/X86InstrCompiler.td
@@ -684,7 +684,7 @@ def OR32mi8Locked  : Ii8<0x83, MRM1m, (outs), (ins i32mem:$dst, i32i8imm:$zero),
 let hasSideEffects = 1, isMeta = 1 in
 def Int_MemBarrier : I<0, Pseudo, (outs), (ins),
                      "#MEMBARRIER",
-                     [(X86MemBarrier)]>, Sched<[WriteLoad]>;
+                     [(membarrier)]>, Sched<[WriteLoad]>;
 
 // RegOpc corresponds to the mr version of the instruction
 // ImmOpc corresponds to the mi version of the instruction

diff --git a/llvm/lib/Target/X86/X86InstrInfo.td b/llvm/lib/Target/X86/X86InstrInfo.td
index 4af7bd6..9a32379 100644 (file)
--- a/llvm/lib/Target/X86/X86InstrInfo.td
+++ b/llvm/lib/Target/X86/X86InstrInfo.td
@@ -135,8 +135,6 @@ def SDTX86Cmpccxadd : SDTypeProfile<1, 4, [SDTCisSameAs<0, 2>,
                                            SDTCisPtrTy<1>, SDTCisSameAs<2, 3>,
                                            SDTCisVT<4, i8>]>;
 
-def X86MemBarrier : SDNode<"X86ISD::MEMBARRIER", SDT_X86MEMBARRIER,
-                            [SDNPHasChain,SDNPSideEffect]>;
 def X86MFence : SDNode<"X86ISD::MFENCE", SDT_X86MEMBARRIER,
                         [SDNPHasChain]>;