commit 848e79c578014f5510fe1e5697431494f4047eca
author Matthias Braun <matze@braunis.de> Fri Feb 19 04:44:19 2016 +0000
committer Matthias Braun <matze@braunis.de> Fri Feb 19 04:44:19 2016 +0000
tree 49962098dec8c38c4740f9307aa9f5188db59bc7
parent 1aff022c9b2e57488b97617e03743b0ab4084df5

LegalizeDAG: Fix ExpandFCOPYSIGN assuming the same type on both inputs

llvm-svn: 261306

llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index e9e7823..93d82de 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -1634,6 +1634,7 @@
   MachinePointerInfo FloatPointerInfo;
   SDValue IntValue;
   APInt SignMask;
+  uint8_t SignBit;
 };
 }
 
@@ -1650,6 +1651,7 @@
   if (TLI.isTypeLegal(IVT)) {
     State.IntValue = DAG.getNode(ISD::BITCAST, DL, IVT, Value);
     State.SignMask = APInt::getSignBit(NumBits);
+    State.SignBit = NumBits - 1;
     return;
   }
 
@@ -1686,6 +1688,7 @@
                                   IntPtr, State.IntPointerInfo, MVT::i8,
                                   false, false, false, 0);
   State.SignMask = APInt::getOneBitSet(LoadTy.getSizeInBits(), 7);
+  State.SignBit = 7;
 }
 
 /// Replace the integer value produced by getSignAsIntValue() with a new value
@@ -1728,15 +1731,38 @@
     return DAG.getSelect(DL, FloatVT, Cond, NegValue, AbsValue);
   }
 
-  // Transform values to integer, copy the sign bit and transform back.
+  // Transform Mag value to integer, and clear the sign bit.
   FloatSignAsInt MagAsInt;
   getSignAsIntValue(MagAsInt, DL, Mag);
-  assert(SignAsInt.SignMask == MagAsInt.SignMask);
-  SDValue ClearSignMask = DAG.getConstant(~SignAsInt.SignMask, DL, IntVT);
-  SDValue ClearedSign = DAG.getNode(ISD::AND, DL, IntVT, MagAsInt.IntValue,
+  EVT MagVT = MagAsInt.IntValue.getValueType();
+  SDValue ClearSignMask = DAG.getConstant(~MagAsInt.SignMask, DL, MagVT);
+  SDValue ClearedSign = DAG.getNode(ISD::AND, DL, MagVT, MagAsInt.IntValue,
                                     ClearSignMask);
-  SDValue CopiedSign = DAG.getNode(ISD::OR, DL, IntVT, ClearedSign, SignBit);
 
+  // Get the signbit at the right position for MagAsInt.
+  int ShiftAmount = SignAsInt.SignBit - MagAsInt.SignBit;
+  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.
+  SDValue CopiedSign = DAG.getNode(ISD::OR, DL, MagVT, ClearedSign, SignBit);
   return modifySignAsInt(MagAsInt, DL, CopiedSign);
 }