diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/CodeGen/RegAllocLocal.cpp | 34 |
1 files changed, 21 insertions, 13 deletions
diff --git a/lib/CodeGen/RegAllocLocal.cpp b/lib/CodeGen/RegAllocLocal.cpp index e0d64cd899..331a291753 100644 --- a/lib/CodeGen/RegAllocLocal.cpp +++ b/lib/CodeGen/RegAllocLocal.cpp @@ -400,19 +400,27 @@ unsigned RA::getReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I, "Couldn't find a register of the appropriate class!"); unsigned R = PhysRegsUseOrder[i]; - // If the current register is compatible, use it. - if (RegInfo->getRegClass(R) == RC) { - PhysReg = R; - break; - } else { - // If one of the registers aliased to the current register is - // compatible, use it. - if (const unsigned *AliasSet = RegInfo->getAliasSet(R)) - for (unsigned a = 0; AliasSet[a]; ++a) - if (RegInfo->getRegClass(AliasSet[a]) == RC) { - PhysReg = AliasSet[a]; // Take an aliased register - break; - } + + // We can only use this register if it holds a virtual register (ie, it + // can be spilled). Do not use it if it is an explicitly allocated + // physical register! + assert(PhysRegsUsed.count(R) && + "PhysReg in PhysRegsUseOrder, but is not allocated?"); + if (PhysRegsUsed[R]) { + // If the current register is compatible, use it. + if (RegInfo->getRegClass(R) == RC) { + PhysReg = R; + break; + } else { + // If one of the registers aliased to the current register is + // compatible, use it. + if (const unsigned *AliasSet = RegInfo->getAliasSet(R)) + for (unsigned a = 0; AliasSet[a]; ++a) + if (RegInfo->getRegClass(AliasSet[a]) == RC) { + PhysReg = AliasSet[a]; // Take an aliased register + break; + } + } } } |