From: Chris Lattner <sabre@nondot.org>
Date: Tue, 7 Jul 2009 23:28:46 +0000 (+0000)
Subject: SelectionDAG::SignBitIsZero doesn't work right for vectors,
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a4f73182450ad6d7197c9229f6396f2e54faefdf;p=oota-llvm.git

SelectionDAG::SignBitIsZero doesn't work right for vectors,
for now, conservatively return false.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74969 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 5f45c980a58..c46eee8a4ed 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1516,6 +1516,10 @@ SDValue SelectionDAG::FoldSetCC(MVT VT, SDValue N1,
 /// SignBitIsZero - Return true if the sign bit of Op is known to be zero.  We
 /// use this predicate to simplify operations downstream.
 bool SelectionDAG::SignBitIsZero(SDValue Op, unsigned Depth) const {
+  // This predicate is not safe for vector operations.
+  if (Op.getValueType().isVector())
+    return false;
+  
   unsigned BitWidth = Op.getValueSizeInBits();
   return MaskedValueIsZero(Op, APInt::getSignBit(BitWidth), Depth);
 }