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author | Owen Anderson <resistor@mac.com> | 2008-11-02 08:08:18 +0000 |
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committer | Owen Anderson <resistor@mac.com> | 2008-11-02 08:08:18 +0000 |
commit | 6423c6c0e8e85d843750f9563180ef7bcfca56c6 (patch) | |
tree | d072e1c8b65b776c4e6e672467dcc81c20ec4179 /lib/CodeGen/PreAllocSplitting.cpp | |
parent | 2b82b7e77ee20eb601ea12f3ed2f686ab838f08f (diff) | |
download | external_llvm-6423c6c0e8e85d843750f9563180ef7bcfca56c6.zip external_llvm-6423c6c0e8e85d843750f9563180ef7bcfca56c6.tar.gz external_llvm-6423c6c0e8e85d843750f9563180ef7bcfca56c6.tar.bz2 |
Don't do pre-splitting if doing so would create a value join that did not
exist before. Updating the live intervals in that care is tricky in the general
case.
Evan, if you see a tighter guard condition for this, let me know.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58560 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/PreAllocSplitting.cpp')
-rw-r--r-- | lib/CodeGen/PreAllocSplitting.cpp | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/lib/CodeGen/PreAllocSplitting.cpp b/lib/CodeGen/PreAllocSplitting.cpp index 8f223b36..4044b73 100644 --- a/lib/CodeGen/PreAllocSplitting.cpp +++ b/lib/CodeGen/PreAllocSplitting.cpp @@ -89,6 +89,8 @@ namespace { AU.addPreservedID(StrongPHIEliminationID); else AU.addPreservedID(PHIEliminationID); + AU.addRequired<MachineLoopInfo>(); + AU.addPreserved<MachineLoopInfo>(); MachineFunctionPass::getAnalysisUsage(AU); } @@ -633,6 +635,14 @@ bool PreAllocSplitting::SplitRegLiveInterval(LiveInterval *LI) { assert(0 && "Val# is defined by a dead def?"); abort(); } + + // Pre-splitting a vreg that does not have a PHI kill across a barrier + // that is within a loop can potentially create a join that was not + // present before, which would make updating the live intervals very + // difficult. Bailout instead. + MachineLoopInfo& MLI = getAnalysis<MachineLoopInfo>(); + if (!ValNo->hasPHIKill && MLI.getLoopFor(BarrierMBB)) + return false; // FIXME: For now, if definition is rematerializable, do not split. MachineInstr *DefMI = (ValNo->def != ~0U) |