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author | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2010-10-06 23:54:39 +0000 |
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committer | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2010-10-06 23:54:39 +0000 |
commit | bf4699c56100a0184bbe4fb53937c7204ca1ceb0 (patch) | |
tree | 71539b0c1c119eca32aa95dcbf80949f41355875 /lib/CodeGen/MachineRegisterInfo.cpp | |
parent | 893ab5d7014dd112fb111a67504bd556be9bd393 (diff) | |
download | llvm-bf4699c56100a0184bbe4fb53937c7204ca1ceb0.tar.gz llvm-bf4699c56100a0184bbe4fb53937c7204ca1ceb0.tar.bz2 llvm-bf4699c56100a0184bbe4fb53937c7204ca1ceb0.tar.xz |
Add MachineRegisterInfo::constrainRegClass and use it in MachineCSE.
This function is intended to be used when inserting a machine instruction that
trivially restricts the legal registers, like LEA requiring a GR32_NOSP
argument.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115875 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/MachineRegisterInfo.cpp')
-rw-r--r-- | lib/CodeGen/MachineRegisterInfo.cpp | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/lib/CodeGen/MachineRegisterInfo.cpp b/lib/CodeGen/MachineRegisterInfo.cpp index 5d852f26be..7b839f07e7 100644 --- a/lib/CodeGen/MachineRegisterInfo.cpp +++ b/lib/CodeGen/MachineRegisterInfo.cpp @@ -60,6 +60,20 @@ MachineRegisterInfo::setRegClass(unsigned Reg, const TargetRegisterClass *RC) { RegClass2VRegMap[RC->getID()].push_back(VR); } +const TargetRegisterClass * +MachineRegisterInfo::constrainRegClass(unsigned Reg, + const TargetRegisterClass *RC) { + const TargetRegisterClass *OldRC = getRegClass(Reg); + if (OldRC == RC) + return RC; + const TargetRegisterClass *NewRC = getCommonSubClass(OldRC, RC); + if (!NewRC) + return 0; + if (NewRC != OldRC) + setRegClass(Reg, NewRC); + return NewRC; +} + /// createVirtualRegister - Create and return a new virtual register in the /// function with the specified register class. /// |