diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/FastISel.cpp | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp index 0a81662e9a3..1896c67d177 100644 --- a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp @@ -131,7 +131,7 @@ void FastISel::flushLocalValueMap() { recomputeInsertPt(); } -bool FastISel::hasTrivialKill(const Value *V) const { +bool FastISel::hasTrivialKill(const Value *V) { // Don't consider constants or arguments to have trivial kills. const Instruction *I = dyn_cast<Instruction>(V); if (!I) @@ -143,6 +143,13 @@ bool FastISel::hasTrivialKill(const Value *V) const { !hasTrivialKill(Cast->getOperand(0))) return false; + // Even the value might have only one use in the LLVM IR, it is possible that + // FastISel might fold the use into another instruction and now there is more + // than one use at the Machine Instruction level. + unsigned Reg = lookUpRegForValue(V); + if (Reg && !MRI.use_empty(Reg)) + return false; + // GEPs with all zero indices are trivially coalesced by fast-isel. if (const GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) if (GEP->hasAllZeroIndices() && !hasTrivialKill(GEP->getOperand(0))) |
