Add ExpandFloatOp_FCOPYSIGN to handle ppcf128-related expansions

We had previously been asserting when faced with a FCOPYSIGN f64, ppcf128 node
because there was no way to expand the FCOPYSIGN node. Because ppcf128 is the
sum of two doubles, and the first double must have the larger magnitude, we
can take the sign from the first double. As a result, in addition to fixing the
crash, this is also an optimization.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188655 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
index facd694..83cad10 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
@@ -1277,6 +1277,7 @@ bool DAGTypeLegalizer::ExpandFloatOperand(SDNode *N, unsigned OpNo) {
   case ISD::EXTRACT_ELEMENT: Res = ExpandOp_EXTRACT_ELEMENT(N); break;
 
   case ISD::BR_CC:      Res = ExpandFloatOp_BR_CC(N); break;
+  case ISD::FCOPYSIGN:  Res = ExpandFloatOp_FCOPYSIGN(N); break;
   case ISD::FP_ROUND:   Res = ExpandFloatOp_FP_ROUND(N); break;
   case ISD::FP_TO_SINT: Res = ExpandFloatOp_FP_TO_SINT(N); break;
   case ISD::FP_TO_UINT: Res = ExpandFloatOp_FP_TO_UINT(N); break;
@@ -1351,6 +1352,17 @@ SDValue DAGTypeLegalizer::ExpandFloatOp_BR_CC(SDNode *N) {
                                 N->getOperand(4)), 0);
 }
 
+SDValue DAGTypeLegalizer::ExpandFloatOp_FCOPYSIGN(SDNode *N) {
+  assert(N->getOperand(1).getValueType() == MVT::ppcf128 &&
+         "Logic only correct for ppcf128!");
+  SDValue Lo, Hi;
+  GetExpandedFloat(N->getOperand(1), Lo, Hi);
+  // The ppcf128 value is providing only the sign; take it from the
+  // higher-order double (which must have the larger magnitude).
+  return DAG.getNode(ISD::FCOPYSIGN, SDLoc(N),
+                     N->getValueType(0), N->getOperand(0), Hi);
+}
+
 SDValue DAGTypeLegalizer::ExpandFloatOp_FP_ROUND(SDNode *N) {
   assert(N->getOperand(0).getValueType() == MVT::ppcf128 &&
          "Logic only correct for ppcf128!");