[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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218677 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrea Di Biagio 2014-09-30 15:30:22 +00:00
parent a66e3bbf7a
commit 9e6df85d39

View File

@ -10423,6 +10423,10 @@ SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) {
// 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 @@ SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) {
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;