[llvm] r338838 - [TargetLowering] Generalise BuildSDIV function

[Simon Pilgrim via llvm-commits]

Author: rksimon
Date: Fri Aug  3 03:00:54 2018
New Revision: 338838

URL: http://llvm.org/viewvc/llvm-project?rev=338838&view=rev
Log:
[TargetLowering] Generalise BuildSDIV function

First step towards a BuildSDIV equivalent to D49248 for non-uniform vector support - this just pushes the splat detection down into TargetLowering::BuildSDIV where its still used.

Differential Revision: https://reviews.llvm.org/D50185

Modified:
    llvm/trunk/include/llvm/CodeGen/TargetLowering.h
    llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
    llvm/trunk/lib/CodeGen/SelectionDAG/TargetLowering.cpp

Modified: llvm/trunk/include/llvm/CodeGen/TargetLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/TargetLowering.h?rev=338838&r1=338837&r2=338838&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/TargetLowering.h (original)
+++ llvm/trunk/include/llvm/CodeGen/TargetLowering.h Fri Aug  3 03:00:54 2018
@@ -3488,8 +3488,7 @@ public:
   //===--------------------------------------------------------------------===//
   // Div utility functions
   //
-  SDValue BuildSDIV(SDNode *N, const APInt &Divisor, SelectionDAG &DAG,
-                    bool IsAfterLegalization,
+  SDValue BuildSDIV(SDNode *N, SelectionDAG &DAG, bool IsAfterLegalization,
                     SmallVectorImpl<SDNode *> &Created) const;
   SDValue BuildUDIV(SDNode *N, const APInt &Divisor, SelectionDAG &DAG,
                     bool IsAfterLegalization,

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=338838&r1=338837&r2=338838&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Fri Aug  3 03:00:54 2018
@@ -18060,21 +18060,14 @@ SDValue DAGCombiner::BuildSDIV(SDNode *N
   if (DAG.getMachineFunction().getFunction().optForMinSize())
     return SDValue();
 
-  ConstantSDNode *C = isConstOrConstSplat(N->getOperand(1));
-  if (!C)
-    return SDValue();
-
-  // Avoid division by zero.
-  if (C->isNullValue())
-    return SDValue();
-
   SmallVector<SDNode *, 8> Built;
-  SDValue S =
-      TLI.BuildSDIV(N, C->getAPIntValue(), DAG, LegalOperations, Built);
+  if (SDValue S = TLI.BuildSDIV(N, DAG, LegalOperations, Built)) {
+    for (SDNode *N : Built)
+      AddToWorklist(N);
+    return S;
+  }
 
-  for (SDNode *N : Built)
-    AddToWorklist(N);
-  return S;
+  return SDValue();
 }
 
 /// Given an ISD::SDIV node expressing a divide by constant power of 2, return a

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/TargetLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/TargetLowering.cpp?rev=338838&r1=338837&r2=338838&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/TargetLowering.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/TargetLowering.cpp Fri Aug  3 03:00:54 2018
@@ -3463,8 +3463,8 @@ SDValue TargetLowering::BuildSDIVPow2(SD
 /// return a DAG expression to select that will generate the same value by
 /// multiplying by a magic number.
 /// Ref: "Hacker's Delight" or "The PowerPC Compiler Writer's Guide".
-SDValue TargetLowering::BuildSDIV(SDNode *N, const APInt &Divisor,
-                                  SelectionDAG &DAG, bool IsAfterLegalization,
+SDValue TargetLowering::BuildSDIV(SDNode *N, SelectionDAG &DAG,
+                                  bool IsAfterLegalization,
                                   SmallVectorImpl<SDNode *> &Created) const {
   EVT VT = N->getValueType(0);
   SDLoc dl(N);
@@ -3474,6 +3474,12 @@ SDValue TargetLowering::BuildSDIV(SDNode
   if (!isTypeLegal(VT))
     return SDValue();
 
+  // TODO: Add non-uniform constant support.
+  ConstantSDNode *C = isConstOrConstSplat(N->getOperand(1));
+  if (!C || C->isNullValue())
+    return SDValue();
+  const APInt &Divisor = C->getAPIntValue();
+
   // If the sdiv has an 'exact' bit we can use a simpler lowering.
   if (N->getFlags().hasExact())
     return BuildExactSDIV(*this, N->getOperand(0), Divisor, dl, DAG, Created);