[llvm-commits] CVS: llvm/lib/Analysis/ScalarEvolution.cpp

[Reid Spencer]

Changes in directory llvm/lib/Analysis:

ScalarEvolution.cpp updated: 1.110 -> 1.111
---
Log message:

For PR1336: http://llvm.org/PR1336 :
Fix a div-by-zero bug noticed by APInt. This fixes:
test/Transforms/IndVarsSimplify/exit_value_tests.llx


---
Diffs of the changes:  (+6 -1)

 ScalarEvolution.cpp |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletion(-)


Index: llvm/lib/Analysis/ScalarEvolution.cpp
diff -u llvm/lib/Analysis/ScalarEvolution.cpp:1.110 llvm/lib/Analysis/ScalarEvolution.cpp:1.111
--- llvm/lib/Analysis/ScalarEvolution.cpp:1.110	Sun Apr 15 14:52:49 2007
+++ llvm/lib/Analysis/ScalarEvolution.cpp	Sun Apr 15 20:48:37 2007
@@ -2125,7 +2125,12 @@
     // Compute the two solutions for the quadratic formula. 
     // The divisions must be performed as signed divisions.
     APInt NegB(-B);
-    APInt TwoA(A << 1);
+    APInt TwoA( A << Two );
+    if (TwoA == 0) {
+      const Type* Ty = LC->getValue()->getType();
+      return std::make_pair(SCEVUnknown::get(UndefValue::get(Ty)),
+                            SCEVUnknown::get(UndefValue::get(Ty)));
+    }
     ConstantInt *Solution1 = ConstantInt::get((NegB + SqrtVal).sdiv(TwoA));
     ConstantInt *Solution2 = ConstantInt::get((NegB - SqrtVal).sdiv(TwoA));