[x86] Start fixing our emission of ADDSUBPS and ADDSUBPD instructions by

introducing a synthetic X86 ISD node representing this generic
operation.

The relevant patterns for mapping these nodes into the concrete
instructions are also added, and a gnarly bit of C++ code in the
target-specific DAG combiner is replaced with simple code emitting this
primitive.

The next step is to generically combine blends of adds and subs into
this node so that we can drop the reliance on an SSE4.1 ISD node
(BLENDI) when matching an SSE3 feature (ADDSUB).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217819 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index b5744e093d2fcfe5706340d68dd2b59a1ba737de..166719b854f057c2e14a02c1344e930a0b3aebe5 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -6501,14 +6501,14 @@ static SDValue matchAddSub(const BuildVectorSDNode *BV, SelectionDAG &DAG,
 
   for (unsigned i = 0, e = NumElts; i != e; i++) {
     SDValue Op = BV->getOperand(i);
-      
+
     // Skip 'undef' values.
     unsigned Opcode = Op.getOpcode();
     if (Opcode == ISD::UNDEF) {
       std::swap(ExpectedOpcode, NextExpectedOpcode);
       continue;
     }
-      
+
     // Early exit if we found an unexpected opcode.
     if (Opcode != ExpectedOpcode)
       return SDValue();
@@ -6565,31 +6565,9 @@ static SDValue matchAddSub(const BuildVectorSDNode *BV, SelectionDAG &DAG,
   // Don't try to fold this build_vector into a VSELECT if it has
   // too many UNDEF operands.
   if (AddFound && SubFound && InVec0.getOpcode() != ISD::UNDEF &&
-      InVec1.getOpcode() != ISD::UNDEF) {
-    // Emit a sequence of vector add and sub followed by a VSELECT.
-    // The new VSELECT will be lowered into a BLENDI.
-    // At ISel stage, we pattern-match the sequence 'add + sub + BLENDI'
-    // and emit a single ADDSUB instruction.
-    SDValue Sub = DAG.getNode(ExpectedOpcode, DL, VT, InVec0, InVec1);
-    SDValue Add = DAG.getNode(NextExpectedOpcode, DL, VT, InVec0, InVec1);
-
-    // Construct the VSELECT mask.
-    EVT MaskVT = VT.changeVectorElementTypeToInteger();
-    EVT SVT = MaskVT.getVectorElementType();
-    unsigned SVTBits = SVT.getSizeInBits();
-    SmallVector<SDValue, 8> Ops;
-
-    for (unsigned i = 0, e = NumElts; i != e; ++i) {
-      APInt Value = i & 1 ? APInt::getNullValue(SVTBits) :
-                            APInt::getAllOnesValue(SVTBits);
-      SDValue Constant = DAG.getConstant(Value, SVT);
-      Ops.push_back(Constant);
-    }
+      InVec1.getOpcode() != ISD::UNDEF)
+    return DAG.getNode(X86ISD::ADDSUB, DL, VT, InVec0, InVec1);
 
-    SDValue Mask = DAG.getNode(ISD::BUILD_VECTOR, DL, MaskVT, Ops);
-    return DAG.getSelect(DL, VT, Mask, Sub, Add);
-  }
-  
   return SDValue();
 }
 

diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index 90d783697212cd4c121abef264b901e40bff7b9b..fef3d74b2d08902dedc0b82e1e8148898bf905cc 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -193,6 +193,9 @@ namespace llvm {
       /// BLENDI - Blend where the selector is an immediate.
       BLENDI,
 
+      /// ADDSUB - Combined add and sub on an FP vector.
+      ADDSUB,
+
       // SUBUS - Integer sub with unsigned saturation.
       SUBUS,
 

diff --git a/lib/Target/X86/X86InstrFragmentsSIMD.td b/lib/Target/X86/X86InstrFragmentsSIMD.td
index eba5ec25136d6dc76de633c063d3567d495e1330..3b777d2407c7b390b0a448b4a977c8b0f5dddaf3 100644 (file)
--- a/lib/Target/X86/X86InstrFragmentsSIMD.td
+++ b/lib/Target/X86/X86InstrFragmentsSIMD.td
@@ -248,6 +248,9 @@ def X86Vextract   : SDNode<"X86ISD::VEXTRACT",  SDTypeProfile<1, 2,
                               [SDTCisVec<1>, SDTCisPtrTy<2>]>, []>;
 
 def X86Blendi    : SDNode<"X86ISD::BLENDI",   SDTBlend>;
+
+def X86Addsub    : SDNode<"X86ISD::ADDSUB", SDTFPBinOp>;
+
 def X86Fmadd     : SDNode<"X86ISD::FMADD",     SDTFma>;
 def X86Fnmadd    : SDNode<"X86ISD::FNMADD",    SDTFma>;
 def X86Fmsub     : SDNode<"X86ISD::FMSUB",     SDTFma>;

diff --git a/lib/Target/X86/X86InstrSSE.td b/lib/Target/X86/X86InstrSSE.td
index 71cc77214aa52073d31d6769243f05cced4f33f1..54eb6f7d4c080181ff818dee7dc26891c4c1a48a 100644 (file)
--- a/lib/Target/X86/X86InstrSSE.td
+++ b/lib/Target/X86/X86InstrSSE.td
@@ -5370,6 +5370,24 @@ let Constraints = "$src1 = $dst", Predicates = [UseSSE3] in {
 
 // Patterns used to select 'addsub' instructions.
 let Predicates = [HasAVX] in {
+  def : Pat<(v4f32 (X86Addsub (v4f32 VR128:$lhs), (v4f32 VR128:$rhs))),
+            (VADDSUBPSrr VR128:$lhs, VR128:$rhs)>;
+  def : Pat<(v4f32 (X86Addsub (v4f32 VR128:$lhs), (v4f32 (memop addr:$rhs)))),
+            (VADDSUBPSrm VR128:$lhs, f128mem:$rhs)>;
+  def : Pat<(v2f64 (X86Addsub (v2f64 VR128:$lhs), (v2f64 VR128:$rhs))),
+            (VADDSUBPDrr VR128:$lhs, VR128:$rhs)>;
+  def : Pat<(v2f64 (X86Addsub (v2f64 VR128:$lhs), (v2f64 (memop addr:$rhs)))),
+            (VADDSUBPDrm VR128:$lhs, f128mem:$rhs)>;
+
+  def : Pat<(v8f32 (X86Addsub (v8f32 VR256:$lhs), (v8f32 VR256:$rhs))),
+            (VADDSUBPSYrr VR256:$lhs, VR256:$rhs)>;
+  def : Pat<(v8f32 (X86Addsub (v8f32 VR256:$lhs), (v8f32 (memop addr:$rhs)))),
+            (VADDSUBPSYrm VR256:$lhs, f256mem:$rhs)>;
+  def : Pat<(v4f64 (X86Addsub (v4f64 VR256:$lhs), (v4f64 VR256:$rhs))),
+            (VADDSUBPDYrr VR256:$lhs, VR256:$rhs)>;
+  def : Pat<(v4f64 (X86Addsub (v4f64 VR256:$lhs), (v4f64 (memop addr:$rhs)))),
+            (VADDSUBPDYrm VR256:$lhs, f256mem:$rhs)>;
+
   // Constant 170 corresponds to the binary mask '10101010'.
   // When used as a blend mask, it allows selecting eight elements from two
   // input vectors as follow:
@@ -5405,6 +5423,15 @@ let Predicates = [HasAVX] in {
 }
 
 let Predicates = [UseSSE3] in {
+  def : Pat<(v4f32 (X86Addsub (v4f32 VR128:$lhs), (v4f32 VR128:$rhs))),
+            (ADDSUBPSrr VR128:$lhs, VR128:$rhs)>;
+  def : Pat<(v4f32 (X86Addsub (v4f32 VR128:$lhs), (v4f32 (memop addr:$rhs)))),
+            (ADDSUBPSrm VR128:$lhs, f128mem:$rhs)>;
+  def : Pat<(v2f64 (X86Addsub (v2f64 VR128:$lhs), (v2f64 VR128:$rhs))),
+            (ADDSUBPDrr VR128:$lhs, VR128:$rhs)>;
+  def : Pat<(v2f64 (X86Addsub (v2f64 VR128:$lhs), (v2f64 (memop addr:$rhs)))),
+            (ADDSUBPDrm VR128:$lhs, f128mem:$rhs)>;
+
   // Constant 10 corresponds to the binary mask '1010'.
   // In the pattern below, it is used as a blend mask to select:
   // - the 1st and 3rd element from the first input vector (the fsub node);