[llvm] r267617 - [LVI] Speculative fix for assertion seen in clang bots

[Philip Reames via llvm-commits]

Author: reames
Date: Tue Apr 26 17:31:53 2016
New Revision: 267617

URL: http://llvm.org/viewvc/llvm-project?rev=267617&view=rev
Log:
[LVI] Speculative fix for assertion seen in clang bots

I'll clean this up and add a test case shortly.  I want to make sure this does actually fix the bots; if not, I'll revert.


Modified:
    llvm/trunk/lib/Analysis/LazyValueInfo.cpp

Modified: llvm/trunk/lib/Analysis/LazyValueInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LazyValueInfo.cpp?rev=267617&r1=267616&r2=267617&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LazyValueInfo.cpp (original)
+++ llvm/trunk/lib/Analysis/LazyValueInfo.cpp Tue Apr 26 17:31:53 2016
@@ -1013,6 +1013,12 @@ bool LazyValueInfoCache::solveBlockValue
 
   const unsigned OperandBitWidth =
     BBI->getOperand(0)->getType()->getPrimitiveSizeInBits();
+  if (OperandBitWidth == 0) {
+    // Without knowing how wide the input is, we can't analyze it in any useful
+    // way.  
+    BBLV.markOverdefined();
+    return true;
+  }
   
   ConstantRange LHSRange = ConstantRange(OperandBitWidth);
   if (hasBlockValue(BBI->getOperand(0), BB)) {