Fix this xform: (sra (shl X, m), result_size) -> (sign_extend (trunc (shl X, result_size - n - m)))
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48578 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index f33946c..f631849 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -2400,7 +2400,9 @@
// If the shift wouldn't be a noop, the truncated type is an actual type,
// and the truncate is free, then proceed with the transform.
- if (ShiftAmt != 0 && TLI.isTruncateFree(VT, TruncVT)) {
+ if (ShiftAmt != 0 &&
+ TLI.isTypeLegal(TruncVT) &&
+ TLI.isTruncateFree(VT, TruncVT)) {
SDOperand Amt = DAG.getConstant(ShiftAmt, TLI.getShiftAmountTy());
SDOperand Shift = DAG.getNode(ISD::SRL, VT, N0.getOperand(0), Amt);
SDOperand Trunc = DAG.getNode(ISD::TRUNCATE, TruncVT, Shift);