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-rw-r--r--lib/CodeGen/SelectionDAG/SelectionDAG.cpp8
1 files changed, 7 insertions, 1 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 0a23966f31..b22bf1dc62 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2192,7 +2192,13 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT VT,
assert(VT == N1.getValueType() &&
"Shift operators return type must be the same as their first arg");
assert(VT.isInteger() && N2.getValueType().isInteger() &&
- VT != MVT::i1 && "Shifts only work on integers");
+ "Shifts only work on integers");
+
+ // Always fold shifts of i1 values so the code generator doesn't need to
+ // handle them. Since we know the size of the shift has to be less than the
+ // size of the value, the shift/rotate count is guaranteed to be zero.
+ if (VT == MVT::i1)
+ return N1;
break;
case ISD::FP_ROUND_INREG: {
MVT EVT = cast<VTSDNode>(N2)->getVT();