Fix FCOPYSIGN expansion

In expansion of FCOPYSIGN, the shift node is missing when the two
operands of FCOPYSIGN are of the same size. We should always generate
shift node (if the required shift bit is not zero) to put the sign
bit into the right position, regardless of the size of underlying
types.

Differential Revision: https://reviews.llvm.org/D49973

llvm-svn: 338665

1 files changed, 12 insertions, 16 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 2b7ba1ffb30..36c43691891 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -1489,24 +1489,20 @@ SDValue SelectionDAGLegalize::ExpandFCOPYSIGN(SDNode *Node) const {
 
   // Get the signbit at the right position for MagAsInt.
   int ShiftAmount = SignAsInt.SignBit - MagAsInt.SignBit;
+  EVT ShiftVT = IntVT;
+  if (SignBit.getValueSizeInBits() < ClearedSign.getValueSizeInBits()) {
+    SignBit = DAG.getNode(ISD::ZERO_EXTEND, DL, MagVT, SignBit);
+    ShiftVT = MagVT;
+  }
+  if (ShiftAmount > 0) {
+    SDValue ShiftCnst = DAG.getConstant(ShiftAmount, DL, ShiftVT);
+    SignBit = DAG.getNode(ISD::SRL, DL, ShiftVT, SignBit, ShiftCnst);
+  } else if (ShiftAmount < 0) {
+    SDValue ShiftCnst = DAG.getConstant(-ShiftAmount, DL, ShiftVT);
+    SignBit = DAG.getNode(ISD::SHL, DL, ShiftVT, SignBit, ShiftCnst);
+  }
   if (SignBit.getValueSizeInBits() > ClearedSign.getValueSizeInBits()) {
-    if (ShiftAmount > 0) {
-      SDValue ShiftCnst = DAG.getConstant(ShiftAmount, DL, IntVT);
-      SignBit = DAG.getNode(ISD::SRL, DL, IntVT, SignBit, ShiftCnst);
-    } else if (ShiftAmount < 0) {
-      SDValue ShiftCnst = DAG.getConstant(-ShiftAmount, DL, IntVT);
-      SignBit = DAG.getNode(ISD::SHL, DL, IntVT, SignBit, ShiftCnst);
-    }
     SignBit = DAG.getNode(ISD::TRUNCATE, DL, MagVT, SignBit);
-  } else if (SignBit.getValueSizeInBits() < ClearedSign.getValueSizeInBits()) {
-    SignBit = DAG.getNode(ISD::ZERO_EXTEND, DL, MagVT, SignBit);
-    if (ShiftAmount > 0) {
-      SDValue ShiftCnst = DAG.getConstant(ShiftAmount, DL, MagVT);
-      SignBit = DAG.getNode(ISD::SRL, DL, MagVT, SignBit, ShiftCnst);
-    } else if (ShiftAmount < 0) {
-      SDValue ShiftCnst = DAG.getConstant(-ShiftAmount, DL, MagVT);
-      SignBit = DAG.getNode(ISD::SHL, DL, MagVT, SignBit, ShiftCnst);
-    }
   }
 
   // Store the part with the modified sign and convert back to float.