Revert "Revert r212640, "Add trunc (select c, a, b) -> select c (trunc a), (trunc b) combine.""
Don't try to convert the select condition type.
llvm-svn: 212750
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 7c42e4d..707e48a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -6022,6 +6022,19 @@
}
}
+ // trunc (select c, a, b) -> select c, (trunc a), (trunc b)
+ if (N0.getOpcode() == ISD::SELECT) {
+ EVT SrcVT = N0.getValueType();
+ if ((!LegalOperations || TLI.isOperationLegal(ISD::SELECT, SrcVT)) &&
+ TLI.isTruncateFree(SrcVT, VT)) {
+ SDLoc SL(N0);
+ SDValue Cond = N0.getOperand(0);
+ SDValue TruncOp0 = DAG.getNode(ISD::TRUNCATE, SL, VT, N0.getOperand(1));
+ SDValue TruncOp1 = DAG.getNode(ISD::TRUNCATE, SL, VT, N0.getOperand(2));
+ return DAG.getNode(ISD::SELECT, SDLoc(N), VT, Cond, TruncOp0, TruncOp1);
+ }
+ }
+
// Fold a series of buildvector, bitcast, and truncate if possible.
// For example fold
// (2xi32 trunc (bitcast ((4xi32)buildvector x, x, y, y) 2xi64)) to