1 files changed, 26 insertions, 9 deletions
diff --git a/lib/CodeGen/RegUsageInfoPropagate.cpp b/lib/CodeGen/RegUsageInfoPropagate.cpp
index 5cc35bfeca63..5b12d00e126f 100644
--- a/lib/CodeGen/RegUsageInfoPropagate.cpp
+++ b/lib/CodeGen/RegUsageInfoPropagate.cpp
@@ -21,6 +21,7 @@
 
 #include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/Passes.h"
@@ -87,14 +88,31 @@ void RegUsageInfoPropagationPass::getAnalysisUsage(AnalysisUsage &AU) const {
   MachineFunctionPass::getAnalysisUsage(AU);
 }
 
+// Assumes call instructions have a single reference to a function.
+static const Function *findCalledFunction(const Module &M, MachineInstr &MI) {
+  for (MachineOperand &MO : MI.operands()) {
+    if (MO.isGlobal())
+      return dyn_cast<Function>(MO.getGlobal());
+
+    if (MO.isSymbol())
+      return M.getFunction(MO.getSymbolName());
+  }
+
+  return nullptr;
+}
+
 bool RegUsageInfoPropagationPass::runOnMachineFunction(MachineFunction &MF) {
-  const Module *M = MF.getFunction()->getParent();
+  const Module *M = MF.getFunction().getParent();
   PhysicalRegisterUsageInfo *PRUI = &getAnalysis<PhysicalRegisterUsageInfo>();
 
   DEBUG(dbgs() << " ++++++++++++++++++++ " << getPassName()
                << " ++++++++++++++++++++  \n");
   DEBUG(dbgs() << "MachineFunction : " << MF.getName() << "\n");
 
+  const MachineFrameInfo &MFI = MF.getFrameInfo();
+  if (!MFI.hasCalls() && !MFI.hasTailCall())
+    return false;
+
   bool Changed = false;
 
   for (MachineBasicBlock &MBB : MF) {
@@ -113,15 +131,14 @@ bool RegUsageInfoPropagationPass::runOnMachineFunction(MachineFunction &MF) {
         Changed = true;
       };
 
-      MachineOperand &Operand = MI.getOperand(0);
-      if (Operand.isGlobal())
-        UpdateRegMask(cast<Function>(Operand.getGlobal()));
-      else if (Operand.isSymbol())
-        UpdateRegMask(M->getFunction(Operand.getSymbolName()));
+      if (const Function *F = findCalledFunction(*M, MI)) {
+        UpdateRegMask(F);
+      } else {
+        DEBUG(dbgs() << "Failed to find call target function\n");
+      }
 
-      DEBUG(dbgs()
-            << "Call Instruction After Register Usage Info Propagation : \n");
-      DEBUG(dbgs() << MI << "\n");
+      DEBUG(dbgs() << "Call Instruction After Register Usage Info Propagation : "
+            << MI << '\n');
     }
   }