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.

llvm-svn: 188655

2 files changed, 13 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
index facd6948b75..83cad10e246 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
+++ b/llvm/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!");
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
index a7262704575..d5d230a49a0 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -482,6 +482,7 @@ private:
   // Float Operand Expansion.
   bool ExpandFloatOperand(SDNode *N, unsigned OperandNo);
   SDValue ExpandFloatOp_BR_CC(SDNode *N);
+  SDValue ExpandFloatOp_FCOPYSIGN(SDNode *N);
   SDValue ExpandFloatOp_FP_ROUND(SDNode *N);
   SDValue ExpandFloatOp_FP_TO_SINT(SDNode *N);
   SDValue ExpandFloatOp_FP_TO_UINT(SDNode *N);