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| author | Matt Arsenault <Matthew.Arsenault@amd.com> | 2016-03-01 18:01:37 +0000 |
|---|---|---|
| committer | Matt Arsenault <Matthew.Arsenault@amd.com> | 2016-03-01 18:01:37 +0000 |
| commit | 03dac8d8e48c2acd3517c028ebbbdeea0628a706 (patch) | |
| tree | ae32e6ef19d67b295465178f615f02ffe67bae73 /llvm/lib/CodeGen/SelectionDAG | |
| parent | e55c1658ea4b2945942ab3d3646258101c75e2e2 (diff) | |
| download | bcm5719-llvm-03dac8d8e48c2acd3517c028ebbbdeea0628a706.tar.gz bcm5719-llvm-03dac8d8e48c2acd3517c028ebbbdeea0628a706.zip | |
DAGCombiner: Turn extract of bitcasted integer into truncate
This reduces the number of bitcast nodes and generally cleans up the
DAG when bitcasting between integers and vectors everywhere.
llvm-svn: 262358
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 3346ea7fb54..d2d48ea936b 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -12180,6 +12180,14 @@ SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) { // converts. } + // extract_vector_elt (v2i32 (bitcast i64:x)), 0 -> i32 (trunc i64:x) + if (ConstEltNo && InVec.getOpcode() == ISD::BITCAST && InVec.hasOneUse() && + ConstEltNo->isNullValue()) { + SDValue BCSrc = InVec.getOperand(0); + if (BCSrc.getValueType().isScalarInteger()) + return DAG.getNode(ISD::TRUNCATE, SDLoc(N), NVT, BCSrc); + } + // Transform: (EXTRACT_VECTOR_ELT( VECTOR_SHUFFLE )) -> EXTRACT_VECTOR_ELT. // We only perform this optimization before the op legalization phase because // we may introduce new vector instructions which are not backed by TD |
