diff options
Diffstat (limited to 'lib/Transforms/Scalar/SCCP.cpp')
| -rw-r--r-- | lib/Transforms/Scalar/SCCP.cpp | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp index 3c92afe8cf..a570ba8b13 100644 --- a/lib/Transforms/Scalar/SCCP.cpp +++ b/lib/Transforms/Scalar/SCCP.cpp @@ -362,8 +362,10 @@ void SCCP::getFeasibleSuccessors(TerminatorInst &TI, std::vector<bool> &Succs) { Succs[0] = true; } else { InstVal &BCValue = getValueState(BI->getCondition()); - if (BCValue.isOverdefined()) { - // Overdefined condition variables mean the branch could go either way. + if (BCValue.isOverdefined() || + (BCValue.isConstant() && !isa<ConstantBool>(BCValue.getConstant()))) { + // Overdefined condition variables, and branches on unfoldable constant + // conditions, mean the branch could go either way. Succs[0] = Succs[1] = true; } else if (BCValue.isConstant()) { // Constant condition variables mean the branch can only go a single way @@ -375,7 +377,8 @@ void SCCP::getFeasibleSuccessors(TerminatorInst &TI, std::vector<bool> &Succs) { Succs[0] = Succs[1] = true; } else if (SwitchInst *SI = dyn_cast<SwitchInst>(&TI)) { InstVal &SCValue = getValueState(SI->getCondition()); - if (SCValue.isOverdefined()) { // Overdefined condition? + if (SCValue.isOverdefined() || // Overdefined condition? + (SCValue.isConstant() && !isa<ConstantInt>(SCValue.getConstant()))) { // All destinations are executable! Succs.assign(TI.getNumSuccessors(), true); } else if (SCValue.isConstant()) { @@ -419,6 +422,9 @@ bool SCCP::isEdgeFeasible(BasicBlock *From, BasicBlock *To) { // Overdefined condition variables mean the branch could go either way. return true; } else if (BCValue.isConstant()) { + // Not branching on an evaluatable constant? + if (!isa<ConstantBool>(BCValue.getConstant())) return true; + // Constant condition variables mean the branch can only go a single way return BI->getSuccessor(BCValue.getConstant() == ConstantBool::False) == To; @@ -435,6 +441,9 @@ bool SCCP::isEdgeFeasible(BasicBlock *From, BasicBlock *To) { return true; } else if (SCValue.isConstant()) { Constant *CPV = SCValue.getConstant(); + if (!isa<ConstantInt>(CPV)) + return true; // not a foldable constant? + // Make sure to skip the "default value" which isn't a value for (unsigned i = 1, E = SI->getNumSuccessors(); i != E; ++i) if (SI->getSuccessorValue(i) == CPV) // Found the taken branch... |