diff options
| -rw-r--r-- | include/llvm/CodeGen/MachineRegisterInfo.h | 8 | ||||
| -rw-r--r-- | lib/CodeGen/MachineRegisterInfo.cpp | 10 |
2 files changed, 11 insertions, 7 deletions
diff --git a/include/llvm/CodeGen/MachineRegisterInfo.h b/include/llvm/CodeGen/MachineRegisterInfo.h index 5eeaa28747..db9352ff88 100644 --- a/include/llvm/CodeGen/MachineRegisterInfo.h +++ b/include/llvm/CodeGen/MachineRegisterInfo.h @@ -215,13 +215,15 @@ public: void setRegClass(unsigned Reg, const TargetRegisterClass *RC); /// constrainRegClass - Constrain the register class of the specified virtual - /// register to be a common subclass of RC and the current register class. - /// Return the new register class, or NULL if no such class exists. + /// register to be a common subclass of RC and the current register class, + /// but only if the new class has at least MinNumRegs registers. Return the + /// new register class, or NULL if no such class exists. /// This should only be used when the constraint is known to be trivial, like /// GR32 -> GR32_NOSP. Beware of increasing register pressure. /// const TargetRegisterClass *constrainRegClass(unsigned Reg, - const TargetRegisterClass *RC); + const TargetRegisterClass *RC, + unsigned MinNumRegs = 0); /// recomputeRegClass - Try to find a legal super-class of Reg's register /// class that still satisfies the constraints from the instructions using diff --git a/lib/CodeGen/MachineRegisterInfo.cpp b/lib/CodeGen/MachineRegisterInfo.cpp index d7953896be..d513f29e7c 100644 --- a/lib/CodeGen/MachineRegisterInfo.cpp +++ b/lib/CodeGen/MachineRegisterInfo.cpp @@ -49,15 +49,17 @@ MachineRegisterInfo::setRegClass(unsigned Reg, const TargetRegisterClass *RC) { const TargetRegisterClass * MachineRegisterInfo::constrainRegClass(unsigned Reg, - const TargetRegisterClass *RC) { + const TargetRegisterClass *RC, + unsigned MinNumRegs) { const TargetRegisterClass *OldRC = getRegClass(Reg); if (OldRC == RC) return RC; const TargetRegisterClass *NewRC = getCommonSubClass(OldRC, RC); - if (!NewRC) + if (!NewRC || NewRC == OldRC) + return NewRC; + if (NewRC->getNumRegs() < MinNumRegs) return 0; - if (NewRC != OldRC) - setRegClass(Reg, NewRC); + setRegClass(Reg, NewRC); return NewRC; } |