1 files changed, 14 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/IfConversion.cpp b/llvm/lib/CodeGen/IfConversion.cpp
index 6359d765da4..3ac78b25854 100644
--- a/llvm/lib/CodeGen/IfConversion.cpp
+++ b/llvm/lib/CodeGen/IfConversion.cpp
@@ -985,8 +985,21 @@ static void UpdatePredRedefs(MachineInstr *MI, LivePhysRegs &Redefs) {
     // take a mutable instruction instead of const.
     MachineInstr *OpMI = const_cast<MachineInstr*>(Op.getParent());
     MachineInstrBuilder MIB(*OpMI->getParent()->getParent(), OpMI);
-    if (Op.isReg())
+    if (Op.isRegMask()) {
+      // First handle regmasks.  They clobber any entries in the mask which
+      // means that we need a def for those registers.
       MIB.addReg(Reg.first, RegState::Implicit | RegState::Undef);
+
+      // We also need to add an implicit def of this register for the later
+      // use to read from.
+      // For the register allocator to have allocated a register clobbered
+      // by the call which is used later, it must be the case that
+      // the call doesn't return.
+      MIB.addReg(Reg.first, RegState::Implicit | RegState::Define);
+      continue;
+    }
+    assert(Op.isReg() && "Register operand required");
+    MIB.addReg(Reg.first, RegState::Implicit | RegState::Undef);
   }
 }