[PATCH] D134875: [AArch64] refactor Opcode selection for LowerMUL (NFC)

[Zain Jaffal via Phabricator via llvm-commits]

zjaffal created this revision.
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Move the logic for selecting `NewOpc` out of `LowerMUL`


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D134875

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


Index: llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -4371,6 +4371,40 @@
   return DAG.getNode(ISD::INTRINSIC_VOID, DL, MVT::Other, Ops2);
 }
 
+unsigned static selectUmullSmull(SDNode *&N0, SDNode *&N1, SelectionDAG &DAG,
+                                 SDLoc DL, bool &isMLA) {
+
+  bool isN0SExt = isSignExtended(N0, DAG);
+  bool isN1SExt = isSignExtended(N1, DAG);
+  if (isN0SExt && isN1SExt)
+    return AArch64ISD::SMULL;
+
+  bool isN0ZExt = isZeroExtended(N0, DAG);
+  bool isN1ZExt = isZeroExtended(N1, DAG);
+
+  if (isN0ZExt && isN1ZExt)
+    return AArch64ISD::UMULL;
+
+  if (!isN1SExt && !isN1ZExt)
+    return 0;
+  // Look for (s/zext A + s/zext B) * (s/zext C). We want to turn these
+  // into (s/zext A * s/zext C) + (s/zext B * s/zext C)
+  if (isN1SExt && isAddSubSExt(N0, DAG)) {
+    isMLA = true;
+    return AArch64ISD::SMULL;
+  }
+  if (isN1ZExt && isAddSubZExt(N0, DAG)) {
+    isMLA = true;
+    return AArch64ISD::UMULL;
+  }
+  if (isN0ZExt && isAddSubZExt(N1, DAG)) {
+    std::swap(N0, N1);
+    isMLA = true;
+    return AArch64ISD::UMULL;
+  }
+  return 0;
+}
+
 SDValue AArch64TargetLowering::LowerMUL(SDValue Op, SelectionDAG &DAG) const {
   EVT VT = Op.getValueType();
 
@@ -4386,32 +4420,9 @@
          "unexpected type for custom-lowering ISD::MUL");
   SDNode *N0 = Op.getOperand(0).getNode();
   SDNode *N1 = Op.getOperand(1).getNode();
-  unsigned NewOpc = 0;
+  SDLoc DL(Op);
   bool isMLA = false;
-  bool isN0SExt = isSignExtended(N0, DAG);
-  bool isN1SExt = isSignExtended(N1, DAG);
-  if (isN0SExt && isN1SExt)
-    NewOpc = AArch64ISD::SMULL;
-  else {
-    bool isN0ZExt = isZeroExtended(N0, DAG);
-    bool isN1ZExt = isZeroExtended(N1, DAG);
-    if (isN0ZExt && isN1ZExt)
-      NewOpc = AArch64ISD::UMULL;
-    else if (isN1SExt || isN1ZExt) {
-      // Look for (s/zext A + s/zext B) * (s/zext C). We want to turn these
-      // into (s/zext A * s/zext C) + (s/zext B * s/zext C)
-      if (isN1SExt && isAddSubSExt(N0, DAG)) {
-        NewOpc = AArch64ISD::SMULL;
-        isMLA = true;
-      } else if (isN1ZExt && isAddSubZExt(N0, DAG)) {
-        NewOpc =  AArch64ISD::UMULL;
-        isMLA = true;
-      } else if (isN0ZExt && isAddSubZExt(N1, DAG)) {
-        std::swap(N0, N1);
-        NewOpc =  AArch64ISD::UMULL;
-        isMLA = true;
-      }
-    }
+  unsigned NewOpc = selectUmullSmull(N0, N1, DAG, DL, isMLA);
 
     if (!NewOpc) {
       if (VT == MVT::v2i64)
@@ -4420,11 +4431,9 @@
       else
         // Other vector multiplications are legal.
         return Op;
-    }
   }
 
   // Legalize to a S/UMULL instruction
-  SDLoc DL(Op);
   SDValue Op0;
   SDValue Op1 = skipExtensionForVectorMULL(N1, DAG);
   if (!isMLA) {


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