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author | Tim Northover <Tim.Northover@arm.com> | 2012-11-20 09:56:11 +0000 |
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committer | Tim Northover <Tim.Northover@arm.com> | 2012-11-20 09:56:11 +0000 |
commit | 310f248c22c5a20eaa4de1e612af3338a89144f3 (patch) | |
tree | 3e4fc3bb0a0e1b1d85dfd2d38284f0c44f494f8a /lib/CodeGen/MachineBasicBlock.cpp | |
parent | 4fe5405bdd2c76108e2d40020374a13d243d14c2 (diff) | |
download | llvm-310f248c22c5a20eaa4de1e612af3338a89144f3.tar.gz llvm-310f248c22c5a20eaa4de1e612af3338a89144f3.tar.bz2 llvm-310f248c22c5a20eaa4de1e612af3338a89144f3.tar.xz |
Fix physical register liveness calculations:
+ Take account of clobbers
+ Give outputs priority over inputs since they happen later.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168360 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/MachineBasicBlock.cpp')
-rw-r--r-- | lib/CodeGen/MachineBasicBlock.cpp | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp index 18d021d521..4406c89aba 100644 --- a/lib/CodeGen/MachineBasicBlock.cpp +++ b/lib/CodeGen/MachineBasicBlock.cpp @@ -982,7 +982,6 @@ MachineBasicBlock::LivenessQueryResult MachineBasicBlock::computeRegisterLiveness(const TargetRegisterInfo *TRI, unsigned Reg, MachineInstr *MI, unsigned Neighborhood) { - unsigned N = Neighborhood; MachineBasicBlock *MBB = MI->getParent(); @@ -997,14 +996,18 @@ MachineBasicBlock::computeRegisterLiveness(const TargetRegisterInfo *TRI, MachineOperandIteratorBase::PhysRegInfo Analysis = MIOperands(I).analyzePhysReg(Reg, TRI); - if (Analysis.Kills) + if (Analysis.Defines) + // Outputs happen after inputs so they take precedence if both are + // present. + return Analysis.DefinesDead ? LQR_Dead : LQR_Live; + + if (Analysis.Kills || Analysis.Clobbers) // Register killed, so isn't live. return LQR_Dead; - else if (Analysis.DefinesOverlap || Analysis.ReadsOverlap) + else if (Analysis.ReadsOverlap) // Defined or read without a previous kill - live. - return (Analysis.Defines || Analysis.Reads) ? - LQR_Live : LQR_OverlappingLive; + return Analysis.Reads ? LQR_Live : LQR_OverlappingLive; } while (I != MBB->begin() && --N > 0); } @@ -1036,7 +1039,7 @@ MachineBasicBlock::computeRegisterLiveness(const TargetRegisterInfo *TRI, return (Analysis.Reads) ? LQR_Live : LQR_OverlappingLive; - else if (Analysis.DefinesOverlap) + else if (Analysis.Clobbers || Analysis.Defines) // Defined (but not read) therefore cannot have been live. return LQR_Dead; } |