Index: lib/Target/ARM/ARMLoadStoreOptimizer.cpp =================================================================== --- lib/Target/ARM/ARMLoadStoreOptimizer.cpp +++ lib/Target/ARM/ARMLoadStoreOptimizer.cpp @@ -1590,6 +1590,11 @@ return false; } +/// Returns true if LDRD/STRD inputs/outputs require a register pair. +static bool doubleMemopsNeedRegPair(const ARMSubtarget &STI) { + return STI.hasV7Ops() || STI.isThumb2(); +} + /// LoadStoreMultipleOpti - An optimization pass to turn multiple LDR / STR /// ops of the same base and incrementing offset into LDM / STM ops. bool ARMLoadStoreOpt::LoadStoreMultipleOpti(MachineBasicBlock &MBB) { @@ -1607,7 +1612,7 @@ RS->enterBasicBlock(&MBB); MachineBasicBlock::iterator MBBI = MBB.begin(), E = MBB.end(); while (MBBI != E) { - if (FixInvalidRegPairOp(MBB, MBBI)) + if (!doubleMemopsNeedRegPair(*STI) && FixInvalidRegPairOp(MBB, MBBI)) continue; bool Advance = false; @@ -2168,9 +2173,11 @@ MBB->erase(Op0); MBB->erase(Op1); - // Add register allocation hints to form register pairs. - MRI->setRegAllocationHint(EvenReg, ARMRI::RegPairEven, OddReg); - MRI->setRegAllocationHint(OddReg, ARMRI::RegPairOdd, EvenReg); + if (doubleMemopsNeedRegPair(*STI)) { + // Add register allocation hints to form register pairs. + MRI->setRegAllocationHint(EvenReg, ARMRI::RegPairEven, OddReg); + MRI->setRegAllocationHint(OddReg, ARMRI::RegPairOdd, EvenReg); + } } else { for (unsigned i = 0; i != NumMove; ++i) { MachineInstr *Op = Ops.back(); Index: test/CodeGen/ARM/ldrd.ll =================================================================== --- test/CodeGen/ARM/ldrd.ll +++ test/CodeGen/ARM/ldrd.ll @@ -92,6 +92,22 @@ ret void } +declare void @extfunc(i32, i32, i32, i32) + +; A8-LABEL: Func2: +; A8: ldrd +; A8: blx +; A8: pop +define void @Func2(i32* %p) { +entry: + %addr0 = getelementptr i32, i32* %p, i32 0 + %addr1 = getelementptr i32, i32* %p, i32 1 + %v0 = load i32, i32* %addr0 + %v1 = load i32, i32* %addr1 + ; try to force %v0/%v1 into non-adjacent registers + call void @extfunc(i32 %v0, i32 0, i32 0, i32 %v1) + ret void +} declare void @llvm.lifetime.start(i64, i8* nocapture) nounwind declare void @llvm.lifetime.end(i64, i8* nocapture) nounwind