[DAG] Check in advance if a build_vector has a legal type before attempting to convert it into a shuffle.
Currently, the DAG Combiner only tries to convert type-legal build_vector nodes
into shuffles. This patch simply moves the logic that checks if a
build_vector has a legal value type up before we even start analyzing the
operands. This allows to early exit immediately from method
'visitBUILD_VECTOR' if the node type is known to be illegal.
No functional change intended.
llvm-svn: 218677
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 2b65cce..aee6455 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -10423,6 +10423,10 @@
// operations. If so, and if the EXTRACT_VECTOR_ELT vector inputs come from
// at most two distinct vectors, turn this into a shuffle node.
+ // Only type-legal BUILD_VECTOR nodes are converted to shuffle nodes.
+ if (!isTypeLegal(VT))
+ return SDValue();
+
// May only combine to shuffle after legalize if shuffle is legal.
if (LegalOperations && !TLI.isOperationLegal(ISD::VECTOR_SHUFFLE, VT))
return SDValue();
@@ -10514,10 +10518,6 @@
VecIn1.getValueType() != VT)
return SDValue();
- // Only type-legal BUILD_VECTOR nodes are converted to shuffle nodes.
- if (!isTypeLegal(VT))
- return SDValue();
-
// Return the new VECTOR_SHUFFLE node.
SDValue Ops[2];
Ops[0] = VecIn1;