diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp b/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp index 16a1c3c1bb5..84ae063941c 100644 --- a/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp +++ b/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp @@ -1229,10 +1229,30 @@ bool ARMLoadStoreOpt::MergeBaseUpdateLSMultiple(MachineInstr *MI) { } else { MergeInstr = findIncDecAfter(MBBI, Base, Pred, PredReg, Offset); if (((Mode != ARM_AM::ia && Mode != ARM_AM::ib) || Offset != Bytes) && - ((Mode != ARM_AM::da && Mode != ARM_AM::db) || Offset != -Bytes)) - return false; + ((Mode != ARM_AM::da && Mode != ARM_AM::db) || Offset != -Bytes)) { + + // We couldn't find an inc/dec to merge. But if the base is dead, we + // can still change to a writeback form as that will save us 2 bytes + // of code size. It can create WAW hazards though, so only do it if + // we're minimizing code size. + if (!MBB.getParent()->getFunction()->optForMinSize() || !BaseKill) + return false; + + bool HighRegsUsed = false; + for (unsigned i = 2, e = MI->getNumOperands(); i != e; ++i) + if (MI->getOperand(i).getReg() >= ARM::R8) { + HighRegsUsed = true; + break; + } + + if (!HighRegsUsed) + MergeInstr = MBB.end(); + else + return false; + } } - MBB.erase(MergeInstr); + if (MergeInstr != MBB.end()) + MBB.erase(MergeInstr); unsigned NewOpc = getUpdatingLSMultipleOpcode(Opcode, Mode); MachineInstrBuilder MIB = BuildMI(MBB, MBBI, DL, TII->get(NewOpc)) |
