[llvm] r321205 - [PowerPC] Added an assert to make sure that the MBBI iterator is valid.

[Stefan Pintilie via llvm-commits]

Author: stefanp
Date: Wed Dec 20 11:07:44 2017
New Revision: 321205

URL: http://llvm.org/viewvc/llvm-project?rev=321205&view=rev
Log:
[PowerPC] Added an assert to make sure that the MBBI iterator is valid.

The function createTailCallBranchInstr assumes that the iterator MBBI is valid.
However, only one use of MBBI is guarded in the function.
Fix this by adding an assert.

Differential Revision: https://reviews.llvm.org/D41358

Modified:
    llvm/trunk/lib/Target/PowerPC/PPCFrameLowering.cpp

Modified: llvm/trunk/lib/Target/PowerPC/PPCFrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCFrameLowering.cpp?rev=321205&r1=321204&r2=321205&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCFrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCFrameLowering.cpp Wed Dec 20 11:07:44 2017
@@ -1531,11 +1531,11 @@ void PPCFrameLowering::emitEpilogue(Mach
 
 void PPCFrameLowering::createTailCallBranchInstr(MachineBasicBlock &MBB) const {
   MachineBasicBlock::iterator MBBI = MBB.getFirstTerminator();
-  DebugLoc dl;
 
-  if (MBBI != MBB.end())
-    dl = MBBI->getDebugLoc();
+  // If we got this far a first terminator should exist.
+  assert(MBBI != MBB.end() && "Failed to find the first terminator.");
 
+  DebugLoc dl = MBBI->getDebugLoc();
   const PPCInstrInfo &TII = *Subtarget.getInstrInfo();
 
   // Create branch instruction for pseudo tail call return instruction