[X86][AVX] Access a scalar float/double as a free extract from a broadcast load (PR43217)

If a fp scalar is loaded and then used as both a scalar and a vector broadcast, perform the load as a broadcast and then extract the scalar for 'free' from the 0th element.

This involved switching the order of the X86ISD::BROADCAST combines so we only convert to X86ISD::BROADCAST_LOAD once all other canonicalizations have been attempted.

Adds a DAGCombinerInfo::recursivelyDeleteUnusedNodes wrapper.

Fixes PR43217

Differential Revision: https://reviews.llvm.org/D68544

llvm-svn: 373871

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 38fd9742d2d..7ea908437ff 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -761,6 +761,11 @@ CombineTo(SDNode *N, SDValue Res0, SDValue Res1, bool AddTo) {
   return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1, AddTo);
 }
 
+bool TargetLowering::DAGCombinerInfo::
+recursivelyDeleteUnusedNodes(SDNode *N) {
+  return ((DAGCombiner*)DC)->recursivelyDeleteUnusedNodes(N);
+}
+
 void TargetLowering::DAGCombinerInfo::
 CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO) {
   return ((DAGCombiner*)DC)->CommitTargetLoweringOpt(TLO);