Re-commit r235560: Switch lowering: extract jump tables and bit tests before building binary tree (PR22262)
Third time's the charm. The previous commit was reverted as a
reverse for-loop in SelectionDAGBuilder::lowerWorkItem did 'I--'
on an iterator at the beginning of a vector, causing asserts
when using debugging iterators. This commit fixes that.
llvm-svn: 235608
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index ddd4b28..f3735cb 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -1413,21 +1413,15 @@
<< FuncInfo->PHINodesToUpdate[i].first
<< ", " << FuncInfo->PHINodesToUpdate[i].second << ")\n");
- const bool MustUpdatePHINodes = SDB->SwitchCases.empty() &&
- SDB->JTCases.empty() &&
- SDB->BitTestCases.empty();
-
// Next, now that we know what the last MBB the LLVM BB expanded is, update
// PHI nodes in successors.
- if (MustUpdatePHINodes) {
- for (unsigned i = 0, e = FuncInfo->PHINodesToUpdate.size(); i != e; ++i) {
- MachineInstrBuilder PHI(*MF, FuncInfo->PHINodesToUpdate[i].first);
- assert(PHI->isPHI() &&
- "This is not a machine PHI node that we are updating!");
- if (!FuncInfo->MBB->isSuccessor(PHI->getParent()))
- continue;
- PHI.addReg(FuncInfo->PHINodesToUpdate[i].second).addMBB(FuncInfo->MBB);
- }
+ for (unsigned i = 0, e = FuncInfo->PHINodesToUpdate.size(); i != e; ++i) {
+ MachineInstrBuilder PHI(*MF, FuncInfo->PHINodesToUpdate[i].first);
+ assert(PHI->isPHI() &&
+ "This is not a machine PHI node that we are updating!");
+ if (!FuncInfo->MBB->isSuccessor(PHI->getParent()))
+ continue;
+ PHI.addReg(FuncInfo->PHINodesToUpdate[i].second).addMBB(FuncInfo->MBB);
}
// Handle stack protector.
@@ -1472,10 +1466,6 @@
SDB->SPDescriptor.resetPerBBState();
}
- // If we updated PHI Nodes, return early.
- if (MustUpdatePHINodes)
- return;
-
for (unsigned i = 0, e = SDB->BitTestCases.size(); i != e; ++i) {
// Lower header first, if it wasn't already lowered
if (!SDB->BitTestCases[i].Emitted) {
@@ -1589,16 +1579,6 @@
}
SDB->JTCases.clear();
- // If the switch block involved a branch to one of the actual successors, we
- // need to update PHI nodes in that block.
- for (unsigned i = 0, e = FuncInfo->PHINodesToUpdate.size(); i != e; ++i) {
- MachineInstrBuilder PHI(*MF, FuncInfo->PHINodesToUpdate[i].first);
- assert(PHI->isPHI() &&
- "This is not a machine PHI node that we are updating!");
- if (FuncInfo->MBB->isSuccessor(PHI->getParent()))
- PHI.addReg(FuncInfo->PHINodesToUpdate[i].second).addMBB(FuncInfo->MBB);
- }
-
// If we generated any switch lowering information, build and codegen any
// additional DAGs necessary.
for (unsigned i = 0, e = SDB->SwitchCases.size(); i != e; ++i) {