diff options
Diffstat (limited to 'lib/CodeGen/PeepholeOptimizer.cpp')
| -rw-r--r-- | lib/CodeGen/PeepholeOptimizer.cpp | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/lib/CodeGen/PeepholeOptimizer.cpp b/lib/CodeGen/PeepholeOptimizer.cpp index ab672c9..81cf901 100644 --- a/lib/CodeGen/PeepholeOptimizer.cpp +++ b/lib/CodeGen/PeepholeOptimizer.cpp @@ -150,6 +150,13 @@ optimizeExtInstr(MachineInstr *MI, MachineBasicBlock *MBB, // No other uses. return false; + // Ensure DstReg can get a register class that actually supports + // sub-registers. Don't change the class until we commit. + const TargetRegisterClass *DstRC = MRI->getRegClass(DstReg); + DstRC = TM->getRegisterInfo()->getSubClassWithSubReg(DstRC, SubIdx); + if (!DstRC) + return false; + // The source has other uses. See if we can replace the other uses with use of // the result of the extension. SmallPtrSet<MachineBasicBlock*, 4> ReachedBBs; @@ -247,8 +254,10 @@ optimizeExtInstr(MachineInstr *MI, MachineBasicBlock *MBB, continue; // About to add uses of DstReg, clear DstReg's kill flags. - if (!Changed) + if (!Changed) { MRI->clearKillFlags(DstReg); + MRI->constrainRegClass(DstReg, DstRC); + } unsigned NewVR = MRI->createVirtualRegister(RC); BuildMI(*UseMBB, UseMI, UseMI->getDebugLoc(), |