[llvm] [XCore] Set MaxAtomicSizeInBitsSupported to 0 (PR #74389)
James Y Knight via llvm-commits
llvm-commits at lists.llvm.org
Mon Dec 4 15:46:51 PST 2023
https://github.com/jyknight created https://github.com/llvm/llvm-project/pull/74389
XCore does not appear to have any support for atomicrmw or cmpxchg.
This will result in all atomic operations getting expanded to __atomic_* libcalls via AtomicExpandPass, which matches what Clang already does in the frontend.
Additionally, remove the code which handles atomic load/store, as it will no longer be used.
>From a3e74bd58b401a569d67539d11d21b33891f5c61 Mon Sep 17 00:00:00 2001
From: James Y Knight <jyknight at google.com>
Date: Thu, 25 Feb 2021 15:13:12 -0500
Subject: [PATCH] [XCore] Set MaxAtomicSizeInBitsSupported to 0
XCore does not appear to have any support for atomicrmw or cmpxchg.
This will result in all atomic operations getting expanded to
__atomic_* libcalls via AtomicExpandPass, which matches what Clang
already does in the frontend.
Additionally, remove the code which handles atomic load/store, as it
will no longer be used.
---
llvm/lib/Target/XCore/XCoreISelLowering.cpp | 92 +--------------------
llvm/lib/Target/XCore/XCoreISelLowering.h | 8 --
llvm/test/CodeGen/XCore/atomic.ll | 72 +++-------------
3 files changed, 15 insertions(+), 157 deletions(-)
diff --git a/llvm/lib/Target/XCore/XCoreISelLowering.cpp b/llvm/lib/Target/XCore/XCoreISelLowering.cpp
index b3dd4de2a769c..045f86c2bd05f 100644
--- a/llvm/lib/Target/XCore/XCoreISelLowering.cpp
+++ b/llvm/lib/Target/XCore/XCoreISelLowering.cpp
@@ -147,12 +147,7 @@ XCoreTargetLowering::XCoreTargetLowering(const TargetMachine &TM,
setOperationAction(ISD::EH_RETURN, MVT::Other, Custom);
setOperationAction(ISD::FRAME_TO_ARGS_OFFSET, MVT::i32, Custom);
- // Atomic operations
- // We request a fence for ATOMIC_* instructions, to reduce them to Monotonic.
- // As we are always Sequential Consistent, an ATOMIC_FENCE becomes a no OP.
setOperationAction(ISD::ATOMIC_FENCE, MVT::Other, Custom);
- setOperationAction(ISD::ATOMIC_LOAD, MVT::i32, Custom);
- setOperationAction(ISD::ATOMIC_STORE, MVT::i32, Custom);
// TRAMPOLINE is custom lowered.
setOperationAction(ISD::INIT_TRAMPOLINE, MVT::Other, Custom);
@@ -171,6 +166,9 @@ XCoreTargetLowering::XCoreTargetLowering(const TargetMachine &TM,
setMinFunctionAlignment(Align(2));
setPrefFunctionAlignment(Align(4));
+
+ // This target doesn't implement native atomics.
+ setMaxAtomicSizeInBitsSupported(0);
}
bool XCoreTargetLowering::isZExtFree(SDValue Val, EVT VT2) const {
@@ -216,8 +214,6 @@ LowerOperation(SDValue Op, SelectionDAG &DAG) const {
case ISD::ADJUST_TRAMPOLINE: return LowerADJUST_TRAMPOLINE(Op, DAG);
case ISD::INTRINSIC_WO_CHAIN: return LowerINTRINSIC_WO_CHAIN(Op, DAG);
case ISD::ATOMIC_FENCE: return LowerATOMIC_FENCE(Op, DAG);
- case ISD::ATOMIC_LOAD: return LowerATOMIC_LOAD(Op, DAG);
- case ISD::ATOMIC_STORE: return LowerATOMIC_STORE(Op, DAG);
default:
llvm_unreachable("unimplemented operand");
}
@@ -928,88 +924,6 @@ LowerATOMIC_FENCE(SDValue Op, SelectionDAG &DAG) const {
return DAG.getNode(ISD::MEMBARRIER, DL, MVT::Other, Op.getOperand(0));
}
-SDValue XCoreTargetLowering::
-LowerATOMIC_LOAD(SDValue Op, SelectionDAG &DAG) const {
- AtomicSDNode *N = cast<AtomicSDNode>(Op);
- assert(N->getOpcode() == ISD::ATOMIC_LOAD && "Bad Atomic OP");
- assert((N->getSuccessOrdering() == AtomicOrdering::Unordered ||
- N->getSuccessOrdering() == AtomicOrdering::Monotonic) &&
- "shouldInsertFencesForAtomic(true) expects unordered / monotonic");
- if (N->getMemoryVT() == MVT::i32) {
- if (N->getAlign() < Align(4))
- report_fatal_error("atomic load must be aligned");
- return DAG.getLoad(getPointerTy(DAG.getDataLayout()), SDLoc(Op),
- N->getChain(), N->getBasePtr(), N->getPointerInfo(),
- N->getAlign(), N->getMemOperand()->getFlags(),
- N->getAAInfo(), N->getRanges());
- }
- if (N->getMemoryVT() == MVT::i16) {
- if (N->getAlign() < Align(2))
- report_fatal_error("atomic load must be aligned");
- return DAG.getExtLoad(ISD::EXTLOAD, SDLoc(Op), MVT::i32, N->getChain(),
- N->getBasePtr(), N->getPointerInfo(), MVT::i16,
- N->getAlign(), N->getMemOperand()->getFlags(),
- N->getAAInfo());
- }
- if (N->getMemoryVT() == MVT::i8)
- return DAG.getExtLoad(ISD::EXTLOAD, SDLoc(Op), MVT::i32, N->getChain(),
- N->getBasePtr(), N->getPointerInfo(), MVT::i8,
- N->getAlign(), N->getMemOperand()->getFlags(),
- N->getAAInfo());
- return SDValue();
-}
-
-SDValue XCoreTargetLowering::
-LowerATOMIC_STORE(SDValue Op, SelectionDAG &DAG) const {
- AtomicSDNode *N = cast<AtomicSDNode>(Op);
- assert(N->getOpcode() == ISD::ATOMIC_STORE && "Bad Atomic OP");
- assert((N->getSuccessOrdering() == AtomicOrdering::Unordered ||
- N->getSuccessOrdering() == AtomicOrdering::Monotonic) &&
- "shouldInsertFencesForAtomic(true) expects unordered / monotonic");
- if (N->getMemoryVT() == MVT::i32) {
- if (N->getAlign() < Align(4))
- report_fatal_error("atomic store must be aligned");
- return DAG.getStore(N->getChain(), SDLoc(Op), N->getVal(), N->getBasePtr(),
- N->getPointerInfo(), N->getAlign(),
- N->getMemOperand()->getFlags(), N->getAAInfo());
- }
- if (N->getMemoryVT() == MVT::i16) {
- if (N->getAlign() < Align(2))
- report_fatal_error("atomic store must be aligned");
- return DAG.getTruncStore(N->getChain(), SDLoc(Op), N->getVal(),
- N->getBasePtr(), N->getPointerInfo(), MVT::i16,
- N->getAlign(), N->getMemOperand()->getFlags(),
- N->getAAInfo());
- }
- if (N->getMemoryVT() == MVT::i8)
- return DAG.getTruncStore(N->getChain(), SDLoc(Op), N->getVal(),
- N->getBasePtr(), N->getPointerInfo(), MVT::i8,
- N->getAlign(), N->getMemOperand()->getFlags(),
- N->getAAInfo());
- return SDValue();
-}
-
-MachineMemOperand::Flags
-XCoreTargetLowering::getTargetMMOFlags(const Instruction &I) const {
- // Because of how we convert atomic_load and atomic_store to normal loads and
- // stores in the DAG, we need to ensure that the MMOs are marked volatile
- // since DAGCombine hasn't been updated to account for atomic, but non
- // volatile loads. (See D57601)
- if (auto *SI = dyn_cast<StoreInst>(&I))
- if (SI->isAtomic())
- return MachineMemOperand::MOVolatile;
- if (auto *LI = dyn_cast<LoadInst>(&I))
- if (LI->isAtomic())
- return MachineMemOperand::MOVolatile;
- if (auto *AI = dyn_cast<AtomicRMWInst>(&I))
- if (AI->isAtomic())
- return MachineMemOperand::MOVolatile;
- if (auto *AI = dyn_cast<AtomicCmpXchgInst>(&I))
- if (AI->isAtomic())
- return MachineMemOperand::MOVolatile;
- return MachineMemOperand::MONone;
-}
-
//===----------------------------------------------------------------------===//
// Calling Convention Implementation
//===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/XCore/XCoreISelLowering.h b/llvm/lib/Target/XCore/XCoreISelLowering.h
index cfd0619cba8fd..d6bf2bcc38c92 100644
--- a/llvm/lib/Target/XCore/XCoreISelLowering.h
+++ b/llvm/lib/Target/XCore/XCoreISelLowering.h
@@ -181,11 +181,6 @@ namespace llvm {
SDValue LowerADJUST_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
SDValue LowerINTRINSIC_WO_CHAIN(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;
-
- MachineMemOperand::Flags getTargetMMOFlags(
- const Instruction &I) const override;
// Inline asm support
std::pair<unsigned, const TargetRegisterClass *>
@@ -224,9 +219,6 @@ namespace llvm {
bool isVarArg,
const SmallVectorImpl<ISD::OutputArg> &ArgsFlags,
LLVMContext &Context) const override;
- bool shouldInsertFencesForAtomic(const Instruction *I) const override {
- return true;
- }
};
}
diff --git a/llvm/test/CodeGen/XCore/atomic.ll b/llvm/test/CodeGen/XCore/atomic.ll
index 02cef0722fc01..8c11e43f52acb 100644
--- a/llvm/test/CodeGen/XCore/atomic.ll
+++ b/llvm/test/CodeGen/XCore/atomic.ll
@@ -21,71 +21,23 @@ define void @atomicloadstore() nounwind {
entry:
; CHECK-LABEL: atomicloadstore
-; CHECK: ldw r[[R0:[0-9]+]], dp[pool]
-; CHECK-NEXT: ldaw r[[R1:[0-9]+]], dp[pool]
-; CHECK-NEXT: #MEMBARRIER
-; CHECK-NEXT: ldc r[[R2:[0-9]+]], 0
- %0 = load atomic i32, ptr @pool acquire, align 4
+; CHECK: __atomic_load_4
+ %0 = load atomic i32, ptr @pool seq_cst, align 4
-; CHECK-NEXT: ld16s r3, r[[R1]][r[[R2]]]
-; CHECK-NEXT: #MEMBARRIER
- %1 = load atomic i16, ptr @pool acquire, align 2
+; CHECK: __atomic_load_2
+ %1 = load atomic i16, ptr @pool seq_cst, align 2
-; CHECK-NEXT: ld8u r11, r[[R1]][r[[R2]]]
-; CHECK-NEXT: #MEMBARRIER
- %2 = load atomic i8, ptr @pool acquire, align 1
+; CHECK: __atomic_load_1
+ %2 = load atomic i8, ptr @pool seq_cst, align 1
-; CHECK-NEXT: ldw r4, dp[pool]
-; CHECK-NEXT: #MEMBARRIER
- %3 = load atomic i32, ptr @pool seq_cst, align 4
+; CHECK: __atomic_store_4
+ store atomic i32 %0, ptr @pool seq_cst, align 4
-; CHECK-NEXT: ld16s r5, r[[R1]][r[[R2]]]
-; CHECK-NEXT: #MEMBARRIER
- %4 = load atomic i16, ptr @pool seq_cst, align 2
+; CHECK: __atomic_store_2
+ store atomic i16 %1, ptr @pool seq_cst, align 2
-; CHECK-NEXT: ld8u r6, r[[R1]][r[[R2]]]
-; CHECK-NEXT: #MEMBARRIER
- %5 = load atomic i8, ptr @pool seq_cst, align 1
-
-; CHECK-NEXT: #MEMBARRIER
-; CHECK-NEXT: stw r[[R0]], dp[pool]
- store atomic i32 %0, ptr @pool release, align 4
-
-; CHECK-NEXT: #MEMBARRIER
-; CHECK-NEXT: st16 r3, r[[R1]][r[[R2]]]
- store atomic i16 %1, ptr @pool release, align 2
-
-; CHECK-NEXT: #MEMBARRIER
-; CHECK-NEXT: st8 r11, r[[R1]][r[[R2]]]
- store atomic i8 %2, ptr @pool release, align 1
-
-; CHECK-NEXT: #MEMBARRIER
-; CHECK-NEXT: stw r4, dp[pool]
-; CHECK-NEXT: #MEMBARRIER
- store atomic i32 %3, ptr @pool seq_cst, align 4
-
-; CHECK-NEXT: #MEMBARRIER
-; CHECK-NEXT: st16 r5, r[[R1]][r[[R2]]]
-; CHECK-NEXT: #MEMBARRIER
- store atomic i16 %4, ptr @pool seq_cst, align 2
-
-; CHECK-NEXT: #MEMBARRIER
-; CHECK-NEXT: st8 r6, r[[R1]][r[[R2]]]
-; CHECK-NEXT: #MEMBARRIER
- store atomic i8 %5, ptr @pool seq_cst, align 1
-
-; CHECK-NEXT: ldw r[[R0]], dp[pool]
-; CHECK-NEXT: stw r[[R0]], dp[pool]
-; CHECK-NEXT: ld16s r[[R0]], r[[R1]][r[[R2]]]
-; CHECK-NEXT: st16 r[[R0]], r[[R1]][r[[R2]]]
-; CHECK-NEXT: ld8u r[[R0]], r[[R1]][r[[R2]]]
-; CHECK-NEXT: st8 r[[R0]], r[[R1]][r[[R2]]]
- %6 = load atomic i32, ptr @pool monotonic, align 4
- store atomic i32 %6, ptr @pool monotonic, align 4
- %7 = load atomic i16, ptr @pool monotonic, align 2
- store atomic i16 %7, ptr @pool monotonic, align 2
- %8 = load atomic i8, ptr @pool monotonic, align 1
- store atomic i8 %8, ptr @pool monotonic, align 1
+; CHECK: __atomic_store_1
+ store atomic i8 %2, ptr @pool seq_cst, align 1
ret void
}
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