diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/AMDGPU/SIInsertWaits.cpp | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/llvm/lib/Target/AMDGPU/SIInsertWaits.cpp b/llvm/lib/Target/AMDGPU/SIInsertWaits.cpp index 3daf13cb4b5..285bc8a8144 100644 --- a/llvm/lib/Target/AMDGPU/SIInsertWaits.cpp +++ b/llvm/lib/Target/AMDGPU/SIInsertWaits.cpp @@ -524,6 +524,16 @@ void SIInsertWaits::handleSendMsg(MachineBasicBlock &MBB, } } +/// Return true if \p MBB has one successor immediately following, and is its +/// only predecessor +static bool hasTrivialSuccessor(const MachineBasicBlock &MBB) { + if (MBB.succ_size() != 1) + return false; + + const MachineBasicBlock *Succ = *MBB.succ_begin(); + return (Succ->pred_size() == 1) && MBB.isLayoutSuccessor(Succ); +} + // FIXME: Insert waits listed in Table 4.2 "Required User-Inserted Wait States" // around other non-memory instructions. bool SIInsertWaits::runOnMachineFunction(MachineFunction &MF) { @@ -642,8 +652,10 @@ bool SIInsertWaits::runOnMachineFunction(MachineFunction &MF) { EndPgmBlocks.push_back(&MBB); } - // Wait for everything at the end of the MBB - Changes |= insertWait(MBB, MBB.getFirstTerminator(), LastIssued); + // Wait for everything at the end of the MBB. If there is only one + // successor, we can defer this until the uses there. + if (!hasTrivialSuccessor(MBB)) + Changes |= insertWait(MBB, MBB.getFirstTerminator(), LastIssued); } if (HaveScalarStores) { |
