[llvm] r371465 - [GlobalISel]: Fix a bug where we could dereference None

[Aditya Nandakumar via llvm-commits]

Author: aditya_nandakumar
Date: Mon Sep  9 15:51:41 2019
New Revision: 371465

URL: http://llvm.org/viewvc/llvm-project?rev=371465&view=rev
Log:
[GlobalISel]: Fix a bug where we could dereference None

getConstantVRegVal returns None when dealing with constants > 64 bits.
Don't assume we always have a value in GISelKnownBits.

Modified:
    llvm/trunk/lib/CodeGen/GlobalISel/GISelKnownBits.cpp

Modified: llvm/trunk/lib/CodeGen/GlobalISel/GISelKnownBits.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/GlobalISel/GISelKnownBits.cpp?rev=371465&r1=371464&r2=371465&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/GlobalISel/GISelKnownBits.cpp (original)
+++ llvm/trunk/lib/CodeGen/GlobalISel/GISelKnownBits.cpp Mon Sep  9 15:51:41 2019
@@ -140,6 +140,8 @@ void GISelKnownBits::computeKnownBitsImp
   }
   case TargetOpcode::G_CONSTANT: {
     auto CstVal = getConstantVRegVal(R, MRI);
+    if (!CstVal)
+      break;
     Known.One = *CstVal;
     Known.Zero = ~Known.One;
     break;