[llvm] r258604 - AArch64ISelLowering: Reduce maximum recursion depth of isConjunctionDisjunctionTree()

[Matthias Braun via llvm-commits]

Author: matze
Date: Fri Jan 22 22:05:18 2016
New Revision: 258604

URL: http://llvm.org/viewvc/llvm-project?rev=258604&view=rev
Log:
AArch64ISelLowering: Reduce maximum recursion depth of isConjunctionDisjunctionTree()

This function will exhibit exponential runtime (2**n) so we should
rather use a lower limit.

Modified:
    llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp

Modified: llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp?rev=258604&r1=258603&r2=258604&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp Fri Jan 22 22:05:18 2016
@@ -1326,8 +1326,8 @@ static bool isConjunctionDisjunctionTree
     CanPushNegate = true;
     return true;
   }
-  // Protect against stack overflow.
-  if (Depth > 15)
+  // Protect against exponential runtime and stack overflow.
+  if (Depth > 6)
     return false;
   if (Opcode == ISD::AND || Opcode == ISD::OR) {
     SDValue O0 = Val->getOperand(0);