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| author | Bill Wendling <isanbard@gmail.com> | 2008-06-23 23:41:14 +0000 |
|---|---|---|
| committer | Bill Wendling <isanbard@gmail.com> | 2008-06-23 23:41:14 +0000 |
| commit | 09d556630a0042c7166fc50ca90a660eab280e21 (patch) | |
| tree | 00ea1623ef1d89a871a3d627a8387500a34e2c1c /lib/CodeGen/LiveVariables.cpp | |
| parent | f02ae79c808c7be63992f2c5042af3bd1c5c6bf2 (diff) | |
| download | external_llvm-09d556630a0042c7166fc50ca90a660eab280e21.zip external_llvm-09d556630a0042c7166fc50ca90a660eab280e21.tar.gz external_llvm-09d556630a0042c7166fc50ca90a660eab280e21.tar.bz2 | |
This situation can occur:
,------.
| |
| v
| t2 = phi ... t1 ...
| |
| v
| t1 = ...
| ... = ... t1 ...
| |
`------'
where there is a use in a PHI node that's a predecessor to the defining
block. We don't want to mark all predecessors as having the value "alive" in
this case. Also, the assert was too restrictive and didn't handle this case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52655 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/LiveVariables.cpp')
| -rw-r--r-- | lib/CodeGen/LiveVariables.cpp | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp index 4a4ef37..bc73b68 100644 --- a/lib/CodeGen/LiveVariables.cpp +++ b/lib/CodeGen/LiveVariables.cpp @@ -139,8 +139,23 @@ void LiveVariables::HandleVirtRegUse(unsigned reg, MachineBasicBlock *MBB, assert(VRInfo.Kills[i]->getParent() != MBB && "entry should be at end!"); #endif - assert(MBB != MRI->getVRegDef(reg)->getParent() && - "Should have kill for defblock!"); + // This situation can occur: + // + // ,------. + // | | + // | v + // | t2 = phi ... t1 ... + // | | + // | v + // | t1 = ... + // | ... = ... t1 ... + // | | + // `------' + // + // where there is a use in a PHI node that's a predecessor to the defining + // block. We don't want to mark all predecessors as having the value "alive" + // in this case. + if (MBB == MRI->getVRegDef(reg)->getParent()) return; // Add a new kill entry for this basic block. If this virtual register is // already marked as alive in this basic block, that means it is alive in at |