From 54d69668b22b8c37aa6e45f14445f3988cc430d4 Mon Sep 17 00:00:00 2001 From: Manman Ren Date: Fri, 29 Jun 2012 19:16:05 +0000 Subject: [PATCH] Add getUniqueVRegDef to MachineRegisterInfo. This comes in handy during peephole optimization. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159453 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/CodeGen/MachineRegisterInfo.h | 5 +++++ lib/CodeGen/MachineRegisterInfo.cpp | 11 +++++++++++ 2 files changed, 16 insertions(+) diff --git a/include/llvm/CodeGen/MachineRegisterInfo.h b/include/llvm/CodeGen/MachineRegisterInfo.h index 5a82caa9acd..2bcd1c72ce9 100644 --- a/include/llvm/CodeGen/MachineRegisterInfo.h +++ b/include/llvm/CodeGen/MachineRegisterInfo.h @@ -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 diff --git a/lib/CodeGen/MachineRegisterInfo.cpp b/lib/CodeGen/MachineRegisterInfo.cpp index 9c0d749a266..863da72774e 100644 --- a/lib/CodeGen/MachineRegisterInfo.cpp +++ b/lib/CodeGen/MachineRegisterInfo.cpp @@ -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()) -- 2.34.1