[AArch64] Don't blindly lower f16/f128 FCCMPs.

Instead, extend f16 (like we do when lowering a standalone SETCC),
and let f128 be legalized to the RT calls.

Fixes PR26803.

llvm-svn: 263301

1 files changed, 16 insertions, 3 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index ecb8eb19c18..cb78d6ddb0f 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -1216,8 +1216,14 @@ static SDValue emitComparison(SDValue LHS, SDValue RHS, ISD::CondCode CC,
                               SDLoc dl, SelectionDAG &DAG) {
   EVT VT = LHS.getValueType();
 
-  if (VT.isFloatingPoint())
+  if (VT.isFloatingPoint()) {
+    assert(VT != MVT::f128);
+    if (VT == MVT::f16) {
+      LHS = DAG.getNode(ISD::FP_EXTEND, dl, MVT::f32, LHS);
+      RHS = DAG.getNode(ISD::FP_EXTEND, dl, MVT::f32, RHS);
+    }
     return DAG.getNode(AArch64ISD::FCMP, dl, VT, LHS, RHS);
+  }
 
   // The CMP instruction is just an alias for SUBS, and representing it as
   // SUBS means that it's possible to get CSE with subtract operations.
@@ -1301,9 +1307,14 @@ static SDValue emitConditionalComparison(SDValue LHS, SDValue RHS,
                                          AArch64CC::CondCode OutCC,
                                          SDLoc DL, SelectionDAG &DAG) {
   unsigned Opcode = 0;
-  if (LHS.getValueType().isFloatingPoint())
+  if (LHS.getValueType().isFloatingPoint()) {
+    assert(LHS.getValueType() != MVT::f128);
+    if (LHS.getValueType() == MVT::f16) {
+      LHS = DAG.getNode(ISD::FP_EXTEND, DL, MVT::f32, LHS);
+      RHS = DAG.getNode(ISD::FP_EXTEND, DL, MVT::f32, RHS);
+    }
     Opcode = AArch64ISD::FCCMP;
-  else if (RHS.getOpcode() == ISD::SUB) {
+  } else if (RHS.getOpcode() == ISD::SUB) {
     SDValue SubOp0 = RHS.getOperand(0);
     if (isNullConstant(SubOp0) && (CC == ISD::SETEQ || CC == ISD::SETNE)) {
       // See emitComparison() on why we can only do this for SETEQ and SETNE.
@@ -1333,6 +1344,8 @@ static bool isConjunctionDisjunctionTree(const SDValue Val, bool &CanNegate,
     return false;
   unsigned Opcode = Val->getOpcode();
   if (Opcode == ISD::SETCC) {
+    if (Val->getOperand(0).getValueType() == MVT::f128)
+      return false;
     CanNegate = true;
     return true;
   }