Lower ARM adds/subs to add/sub after adding optional CPSR operand.

This is still a hack until we can teach tblgen to generate the
optional CPSR operand rather than an implicit CPSR def. But the
strangeness is now limited to the selection DAG. ADD/SUB MI's no
longer have implicit CPSR defs, nor do we allow flag setting variants
of these opcodes in machine code. There are several corner cases to
consider, and getting one wrong would previously lead to nasty
miscompilation. It's not the first time I've debugged one, so this
time I added enough verification to ensure it won't happen again.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140228 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 5 insertions, 6 deletions

diff --git a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
index e2e906afa6..000a7dfcd6 100644
--- a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
+++ b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
@@ -763,7 +763,9 @@ EmitMachineNode(SDNode *Node, bool IsClone, bool IsCloned,
     }
 
   // Run post-isel target hook to adjust this instruction if needed.
+#ifdef NDEBUG
   if (II.hasPostISelHook())
+#endif
     TLI->AdjustInstrPostInstrSelection(MI, Node);
 }
 
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index b684619776..5b4ade2681 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -179,12 +179,9 @@ TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
 
 void TargetLowering::AdjustInstrPostInstrSelection(MachineInstr *MI,
                                                    SDNode *Node) const {
-#ifndef NDEBUG
-  dbgs() << "If a target marks an instruction with "
-          "'hasPostISelHook', it must implement "
-          "TargetLowering::AdjustInstrPostInstrSelection!";
-#endif
-  llvm_unreachable(0);
+  assert(!MI->getDesc().hasPostISelHook() &&
+         "If a target marks an instruction with 'hasPostISelHook', "
+         "it must implement TargetLowering::AdjustInstrPostInstrSelection!");
 }
 
 //===----------------------------------------------------------------------===//