[MachineVerifier] Analyze MachineMemOperands for mem-to-mem moves.

[oota-llvm.git] / lib / CodeGen / MachineVerifier.cpp

diff --git a/lib/CodeGen/MachineVerifier.cpp b/lib/CodeGen/MachineVerifier.cpp
index b9ca0c51d76feb5d813bf4444e562ec2731be0e1..25035fdd59d4b4ebca96442326e9bc8fe728a8df 100644 (file)
--- a/lib/CodeGen/MachineVerifier.cpp
+++ b/lib/CodeGen/MachineVerifier.cpp
@@ -992,15 +992,34 @@ MachineVerifier::visitMachineOperand(const MachineOperand *MO, unsigned MONum) {
   case MachineOperand::MO_FrameIndex:
     if (LiveStks && LiveStks->hasInterval(MO->getIndex()) &&
         LiveInts && !LiveInts->isNotInMIMap(MI)) {
-      LiveInterval &LI = LiveStks->getInterval(MO->getIndex());
+      int FI = MO->getIndex();
+      LiveInterval &LI = LiveStks->getInterval(FI);
       SlotIndex Idx = LiveInts->getInstructionIndex(MI);
 
-      // For a memory-to-memory move, we don't know if MI is using
-      // this frame index for loading or storing, so check for
-      // liveness at reg-slot only in the simple load case.
       bool stores = MI->mayStore();
-      bool simpleLoad = (MI->mayLoad() && !stores);
-      if (simpleLoad && !LI.liveAt(Idx.getRegSlot(true))) {
+      bool loads = MI->mayLoad();
+      // For a memory-to-memory move, we need to check if the frame
+      // index is used for storing or loading, by inspecting the
+      // memory operands.
+      if (stores && loads) {
+        for (auto *MMO : MI->memoperands()) {
+          const PseudoSourceValue *PSV = MMO->getPseudoValue();
+          if (PSV == nullptr) continue;
+          const FixedStackPseudoSourceValue *Value =
+            dyn_cast<FixedStackPseudoSourceValue>(PSV);
+          if (Value == nullptr) continue;
+          if (Value->getFrameIndex() != FI) continue;
+
+          if (MMO->isStore())
+            loads = false;
+          else
+            stores = false;
+          break;
+        }
+        if (loads == stores)
+          report("Missing fixed stack memoperand.", MI);
+      }
+      if (loads && !LI.liveAt(Idx.getRegSlot(true))) {
         report("Instruction loads from dead spill slot", MO, MONum);
         errs() << "Live stack: " << LI << '\n';
       }