[llvm] b74c4db - [SVE] Move INT_TO_FP i1 promotion into custom lowering.

[Paul Walker via llvm-commits]

Author: Paul Walker
Date: 2020-12-15T11:57:07Z
New Revision: b74c4dbb9634f6210c6539fb4c09b0b68cb3cf0a

URL: https://github.com/llvm/llvm-project/commit/b74c4dbb9634f6210c6539fb4c09b0b68cb3cf0a
DIFF: https://github.com/llvm/llvm-project/commit/b74c4dbb9634f6210c6539fb4c09b0b68cb3cf0a.diff

LOG: [SVE] Move INT_TO_FP i1 promotion into custom lowering.

AddPromotedToType is being used to legalise INT_TO_FP operations
when the source is a predicate. The point where this introduces
vector extends might cause problems in the future so this patch
falls back to manual promotion within custom lowering.

Differential Revision: https://reviews.llvm.org/D90093

Added: 
    

Modified: 
    llvm/lib/Target/AArch64/AArch64ISelLowering.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 0d4dba6dcecf..f7ba135ad946 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -147,7 +147,7 @@ static inline EVT getPackedSVEVectorVT(EVT VT) {
   }
 }
 
-static inline MVT getPromotedVTForPredicate(MVT VT) {
+static inline EVT getPromotedVTForPredicate(EVT VT) {
   assert(VT.isScalableVector() && (VT.getVectorElementType() == MVT::i1) &&
          "Expected scalable predicate vector type!");
   switch (VT.getVectorMinNumElements()) {
@@ -1113,10 +1113,8 @@ AArch64TargetLowering::AArch64TargetLowering(const TargetMachine &TM,
 
       // There are no legal MVT::nxv16f## based types.
       if (VT != MVT::nxv16i1) {
-        setOperationAction(ISD::SINT_TO_FP, VT, Promote);
-        AddPromotedToType(ISD::SINT_TO_FP, VT, getPromotedVTForPredicate(VT));
-        setOperationAction(ISD::UINT_TO_FP, VT, Promote);
-        AddPromotedToType(ISD::UINT_TO_FP, VT, getPromotedVTForPredicate(VT));
+        setOperationAction(ISD::SINT_TO_FP, VT, Custom);
+        setOperationAction(ISD::UINT_TO_FP, VT, Custom);
       }
     }
 
@@ -3179,11 +3177,20 @@ SDValue AArch64TargetLowering::LowerVectorINT_TO_FP(SDValue Op,
   SDLoc dl(Op);
   SDValue In = Op.getOperand(0);
   EVT InVT = In.getValueType();
+  unsigned Opc = Op.getOpcode();
+  bool IsSigned = Opc == ISD::SINT_TO_FP || Opc == ISD::STRICT_SINT_TO_FP;
 
   if (VT.isScalableVector()) {
-    unsigned Opcode = Op.getOpcode() == ISD::UINT_TO_FP
-                          ? AArch64ISD::UINT_TO_FP_MERGE_PASSTHRU
-                          : AArch64ISD::SINT_TO_FP_MERGE_PASSTHRU;
+    if (InVT.getVectorElementType() == MVT::i1) {
+      // We can't directly extend an SVE predicate; extend it first.
+      unsigned CastOpc = IsSigned ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND;
+      EVT CastVT = getPromotedVTForPredicate(InVT);
+      In = DAG.getNode(CastOpc, dl, CastVT, In);
+      return DAG.getNode(Opc, dl, VT, In);
+    }
+
+    unsigned Opcode = IsSigned ? AArch64ISD::SINT_TO_FP_MERGE_PASSTHRU
+                               : AArch64ISD::UINT_TO_FP_MERGE_PASSTHRU;
     return LowerToPredicatedOp(Op, DAG, Opcode);
   }
 
@@ -3193,16 +3200,15 @@ SDValue AArch64TargetLowering::LowerVectorINT_TO_FP(SDValue Op,
     MVT CastVT =
         MVT::getVectorVT(MVT::getFloatingPointVT(InVT.getScalarSizeInBits()),
                          InVT.getVectorNumElements());
-    In = DAG.getNode(Op.getOpcode(), dl, CastVT, In);
+    In = DAG.getNode(Opc, dl, CastVT, In);
     return DAG.getNode(ISD::FP_ROUND, dl, VT, In, DAG.getIntPtrConstant(0, dl));
   }
 
   if (VTSize > InVTSize) {
-    unsigned CastOpc =
-        Op.getOpcode() == ISD::SINT_TO_FP ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND;
+    unsigned CastOpc = IsSigned ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND;
     EVT CastVT = VT.changeVectorElementTypeToInteger();
     In = DAG.getNode(CastOpc, dl, CastVT, In);
-    return DAG.getNode(Op.getOpcode(), dl, VT, In);
+    return DAG.getNode(Opc, dl, VT, In);
   }
 
   return Op;