diff options
author | Evan Cheng <evan.cheng@apple.com> | 2009-06-15 08:28:29 +0000 |
---|---|---|
committer | Evan Cheng <evan.cheng@apple.com> | 2009-06-15 08:28:29 +0000 |
commit | 358dec51804ee52e47ea3a47c9248086e458ad7c (patch) | |
tree | 55cae00b3830a7107f21212681aec06a9a79dc4f /lib/CodeGen/VirtRegMap.cpp | |
parent | d3b295c23fe945c992e7ffc29962248a0e573ea2 (diff) |
Part 1.
- Change register allocation hint to a pair of unsigned integers. The hint type is zero (which means prefer the register specified as second part of the pair) or entirely target dependent.
- Allow targets to specify alternative register allocation orders based on allocation hint.
Part 2.
- Use the register allocation hint system to implement more aggressive load / store multiple formation.
- Aggressively form LDRD / STRD. These are formed *before* register allocation. It has to be done this way to shorten live interval of base and offset registers. e.g.
v1025 = LDR v1024, 0
v1026 = LDR v1024, 0
=>
v1025,v1026 = LDRD v1024, 0
If this transformation isn't done before allocation, v1024 will overlap v1025 which means it more difficult to allocate a register pair.
- Even with the register allocation hint, it may not be possible to get the desired allocation. In that case, the post-allocation load / store multiple pass must fix the ldrd / strd instructions. They can either become ldm / stm instructions or back to a pair of ldr / str instructions.
This is work in progress, not yet enabled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73381 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/VirtRegMap.cpp')
-rw-r--r-- | lib/CodeGen/VirtRegMap.cpp | 39 |
1 files changed, 9 insertions, 30 deletions
diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp index 87d75dd006..4d3417fdff 100644 --- a/lib/CodeGen/VirtRegMap.cpp +++ b/lib/CodeGen/VirtRegMap.cpp @@ -100,36 +100,15 @@ void VirtRegMap::grow() { } unsigned VirtRegMap::getRegAllocPref(unsigned virtReg) { - std::pair<MachineRegisterInfo::RegAllocHintType, unsigned> Hint = - MRI->getRegAllocationHint(virtReg); - switch (Hint.first) { - default: assert(0); - case MachineRegisterInfo::RA_None: - return 0; - case MachineRegisterInfo::RA_Preference: - if (TargetRegisterInfo::isPhysicalRegister(Hint.second)) - return Hint.second; - if (hasPhys(Hint.second)) - return getPhys(Hint.second); - case MachineRegisterInfo::RA_PairEven: { - unsigned physReg = Hint.second; - if (TargetRegisterInfo::isPhysicalRegister(physReg)) - return TRI->getRegisterPairEven(*MF, physReg); - else if (hasPhys(physReg)) - return TRI->getRegisterPairEven(*MF, getPhys(physReg)); - return 0; - } - case MachineRegisterInfo::RA_PairOdd: { - unsigned physReg = Hint.second; - if (TargetRegisterInfo::isPhysicalRegister(physReg)) - return TRI->getRegisterPairOdd(*MF, physReg); - else if (hasPhys(physReg)) - return TRI->getRegisterPairOdd(*MF, getPhys(physReg)); - return 0; - } - } - // Shouldn't reach here. - return 0; + std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(virtReg); + unsigned physReg = Hint.second; + if (physReg && + TargetRegisterInfo::isVirtualRegister(physReg) && hasPhys(physReg)) + physReg = getPhys(physReg); + if (Hint.first == 0) + return (physReg && TargetRegisterInfo::isPhysicalRegister(physReg)) + ? physReg : 0; + return TRI->ResolveRegAllocHint(Hint.first, physReg, *MF); } int VirtRegMap::assignVirt2StackSlot(unsigned virtReg) { |