[pr19636] Fix known bit computation in urem instruction with power of two.
Patch by Andrey Kuharev.
llvm-svn: 209902
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 51ae11d..65a3f0a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2185,8 +2185,11 @@
const APInt &RA = Rem->getAPIntValue();
if (RA.isPowerOf2()) {
APInt LowBits = (RA - 1);
- KnownZero |= ~LowBits;
- computeKnownBits(Op.getOperand(0), KnownZero, KnownOne,Depth+1);
+ computeKnownBits(Op.getOperand(0), KnownZero2, KnownOne2, Depth + 1);
+
+ // The upper bits are all zero, the lower ones are unchanged.
+ KnownZero = KnownZero2 | ~LowBits;
+ KnownOne = KnownOne2 & LowBits;
break;
}
}