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Add getUniqueVRegDef to MachineRegisterInfo. 

This comes in handy during peephole optimization.

llvm-svn: 159453
This commit is contained in:
Manman Ren 2012-06-29 19:16:05 +00:00
parent 9699c1ef38
commit c146589aa4
2 changed files with 16 additions and 0 deletions
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5
llvm/include/llvm/CodeGen/MachineRegisterInfo.h
View File

@ -237,6 +237,11 @@ public:
/// form, so there should only be one definition.
MachineInstr *getVRegDef(unsigned Reg) const;
/// getUniqueVRegDef - Return the unique machine instr that defines the
/// specified virtual register or null if none is found. If there are
/// multiple definitions or no definition, return null.
MachineInstr *getUniqueVRegDef(unsigned Reg) const;
/// clearKillFlags - Iterate over all the uses of the given register and
/// clear the kill flag from the MachineOperand. This function is used by
/// optimization passes which extend register lifetimes and need only

11
llvm/lib/CodeGen/MachineRegisterInfo.cpp
View File

@ -165,6 +165,17 @@ MachineInstr *MachineRegisterInfo::getVRegDef(unsigned Reg) const {
return !I.atEnd() ? &*I : 0;
}
/// getUniqueVRegDef - Return the unique machine instr that defines the
/// specified virtual register or null if none is found. If there are
/// multiple definitions or no definition, return null.
MachineInstr *MachineRegisterInfo::getUniqueVRegDef(unsigned Reg) const {
if (def_empty(Reg)) return 0;
def_iterator I = def_begin(Reg);
if (llvm::next(I) != def_end())
return 0;
return &*I;
}
bool MachineRegisterInfo::hasOneUse(unsigned RegNo) const {
use_iterator UI = use_begin(RegNo);
if (UI == use_end())