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author | Evan Cheng <evan.cheng@apple.com> | 2009-06-04 20:28:22 +0000 |
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committer | Evan Cheng <evan.cheng@apple.com> | 2009-06-04 20:28:22 +0000 |
commit | 550aacb978a8391f605c6ec1feca7d797415d38b (patch) | |
tree | 1f609e40d40fbe1c28443ee1de37f54632dbe4d7 /lib | |
parent | cd0c4ac7fb29ce5fb569a7ed6c5daf44fac06971 (diff) | |
download | external_llvm-550aacb978a8391f605c6ec1feca7d797415d38b.zip external_llvm-550aacb978a8391f605c6ec1feca7d797415d38b.tar.gz external_llvm-550aacb978a8391f605c6ec1feca7d797415d38b.tar.bz2 |
A value defined by an implicit_def can be liven to a use BB. This is unfortunate. But register allocator still has to add it to the live-in set of the use BB.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72889 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r-- | lib/CodeGen/RegAllocLinearScan.cpp | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/lib/CodeGen/RegAllocLinearScan.cpp b/lib/CodeGen/RegAllocLinearScan.cpp index 0ef97c1..ab4068e 100644 --- a/lib/CodeGen/RegAllocLinearScan.cpp +++ b/lib/CodeGen/RegAllocLinearScan.cpp @@ -542,6 +542,24 @@ void RALinScan::linearScan() // Ignore splited live intervals. if (!isPhys && vrm_->getPreSplitReg(cur.reg)) continue; + + // A register defined by an implicit_def can be liveout the def BB and livein + // to a use BB. Add it to the livein set of the use BB's. + if (!isPhys && cur.empty()) { + if (MachineInstr *DefMI = mri_->getVRegDef(cur.reg)) { + assert(DefMI->getOpcode() == TargetInstrInfo::IMPLICIT_DEF); + MachineBasicBlock *DefMBB = DefMI->getParent(); + SmallPtrSet<MachineBasicBlock*, 4> Seen; + Seen.insert(DefMBB); + for (MachineRegisterInfo::reg_iterator ri = mri_->reg_begin(cur.reg), + re = mri_->reg_end(); ri != re; ++ri) { + MachineInstr *UseMI = &*ri; + MachineBasicBlock *UseMBB = UseMI->getParent(); + if (Seen.insert(UseMBB)) + UseMBB->addLiveIn(Reg); + } + } + } for (LiveInterval::Ranges::const_iterator I = cur.begin(), E = cur.end(); I != E; ++I) { const LiveRange &LR = *I; |