diff options
| -rw-r--r-- | llvm/lib/Target/ARM/ARMISelLowering.cpp | 6 | ||||
| -rw-r--r-- | llvm/lib/Target/ARM/ARMInstrInfo.td | 7 | ||||
| -rw-r--r-- | llvm/test/CodeGen/ARM/fence-singlethread.ll | 16 |
3 files changed, 28 insertions, 1 deletions
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp index 165e9b7378c..0f8cdad983d 100644 --- a/llvm/lib/Target/ARM/ARMISelLowering.cpp +++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp @@ -3358,8 +3358,12 @@ ARMTargetLowering::LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG, static SDValue LowerATOMIC_FENCE(SDValue Op, SelectionDAG &DAG, const ARMSubtarget *Subtarget) { - // FIXME: handle "fence singlethread" more efficiently. SDLoc dl(Op); + ConstantSDNode *ScopeN = cast<ConstantSDNode>(Op.getOperand(2)); + auto Scope = static_cast<SynchronizationScope>(ScopeN->getZExtValue()); + if (Scope == SynchronizationScope::SingleThread) + return Op; + if (!Subtarget->hasDataBarrier()) { // Some ARMv6 cpus can support data barriers with an mcr instruction. // Thumb1 and pre-v6 ARM mode use a libcall instead and should never get diff --git a/llvm/lib/Target/ARM/ARMInstrInfo.td b/llvm/lib/Target/ARM/ARMInstrInfo.td index 703e8071b17..9d8ee5c3f9d 100644 --- a/llvm/lib/Target/ARM/ARMInstrInfo.td +++ b/llvm/lib/Target/ARM/ARMInstrInfo.td @@ -5975,3 +5975,10 @@ def CMP_SWAP_64 : PseudoInst<(outs GPRPair:$Rd, GPR:$status), (ins GPR:$addr, GPRPair:$desired, GPRPair:$new), NoItinerary, []>, Sched<[]>; } + +def CompilerBarrier : PseudoInst<(outs), (ins i32imm:$ordering), NoItinerary, + [(atomic_fence imm:$ordering, 0)]> { + let hasSideEffects = 1; + let Size = 0; + let AsmString = "@ COMPILER BARRIER"; +} diff --git a/llvm/test/CodeGen/ARM/fence-singlethread.ll b/llvm/test/CodeGen/ARM/fence-singlethread.ll new file mode 100644 index 00000000000..ec032ccac42 --- /dev/null +++ b/llvm/test/CodeGen/ARM/fence-singlethread.ll @@ -0,0 +1,16 @@ +; RUN: llc -mtriple=thumbv7-linux-gnueabihf %s -o - | FileCheck %s +; RUN: llc -mtriple=thumbv7-apple-ios %s -o - | FileCheck %s +; RUN: llc -mtriple=thumbv7-linux-gnueabihf %s -filetype=obj -o %t +; RUN: llvm-objdump -d %t | FileCheck %s --check-prefix=OBJ + +; OBJ-NOT: dmb + +define void @fence_singlethread() { +; CHECK-LABEL: fence_singlethread: +; CHECK-NOT: dmb +; CHECK: @ COMPILER BARRIER +; CHECK-NOT: dmb + + fence singlethread seq_cst + ret void +} |
