[X86] Add combineX86ShufflesRecursively helper. NFCI.

combineX86ShufflesRecursively is pretty cumbersome with a lot of arguments that only matter later in recursion.

This commit adds a wrapper version that only takes the initial root Op to simplify calls that don't need to worry about these.

An early, cleanup step towards merging combineX86ShufflesRecursively into SimplifyDemandedVectorElts/SimplifyDemandedBits.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351352 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index fd00185..f0f5f6f 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -31624,6 +31624,14 @@
                                 AllowVariableMask, DAG, Subtarget);
 }
 
+/// Helper entry wrapper to combineX86ShufflesRecursively.
+static SDValue combineX86ShufflesRecursively(SDValue Op, SelectionDAG &DAG,
+                                             const X86Subtarget &Subtarget) {
+  return combineX86ShufflesRecursively({Op}, 0, Op, {0}, {}, /*Depth*/ 1,
+                                       /*HasVarMask*/ false,
+                                       /*AllowVarMask*/ true, DAG, Subtarget);
+}
+
 /// Get the PSHUF-style mask from PSHUF node.
 ///
 /// This is a very minor wrapper around getTargetShuffleMask to easy forming v4
@@ -32434,9 +32442,7 @@
     // specific PSHUF instruction sequences into their minimal form so that we
     // can evaluate how many specialized shuffle instructions are involved in
     // a particular chain.
-    if (SDValue Res = combineX86ShufflesRecursively(
-            {Op}, 0, Op, {0}, {}, /*Depth*/ 1,
-            /*HasVarMask*/ false, /*AllowVarMask*/ true, DAG, Subtarget))
+    if (SDValue Res = combineX86ShufflesRecursively(Op, DAG, Subtarget))
       return Res;
 
     // Simplify source operands based on shuffle mask.
@@ -35819,10 +35825,7 @@
 
   // Attempt to combine as shuffle.
   SDValue Op(N, 0);
-  if (SDValue Res =
-          combineX86ShufflesRecursively({Op}, 0, Op, {0}, {}, /*Depth*/ 1,
-                                        /*HasVarMask*/ false,
-                                        /*AllowVarMask*/ true, DAG, Subtarget))
+  if (SDValue Res = combineX86ShufflesRecursively(Op, DAG, Subtarget))
     return Res;
 
   return SDValue();
@@ -35898,9 +35901,7 @@
   // We can decode 'whole byte' logical bit shifts as shuffles.
   if (LogicalShift && (ShiftVal % 8) == 0) {
     SDValue Op(N, 0);
-    if (SDValue Res = combineX86ShufflesRecursively(
-            {Op}, 0, Op, {0}, {}, /*Depth*/ 1,
-            /*HasVarMask*/ false, /*AllowVarMask*/ true, DAG, Subtarget))
+    if (SDValue Res = combineX86ShufflesRecursively(Op, DAG, Subtarget))
       return Res;
   }
 
@@ -35941,10 +35942,7 @@
 
   // Attempt to combine PINSRB/PINSRW patterns to a shuffle.
   SDValue Op(N, 0);
-  if (SDValue Res =
-          combineX86ShufflesRecursively({Op}, 0, Op, {0}, {}, /*Depth*/ 1,
-                                        /*HasVarMask*/ false,
-                                        /*AllowVarMask*/ true, DAG, Subtarget))
+  if (SDValue Res = combineX86ShufflesRecursively(Op, DAG, Subtarget))
     return Res;
 
   return SDValue();
@@ -36461,9 +36459,7 @@
   // Attempt to recursively combine a bitmask AND with shuffles.
   if (VT.isVector() && (VT.getScalarSizeInBits() % 8) == 0) {
     SDValue Op(N, 0);
-    if (SDValue Res = combineX86ShufflesRecursively(
-            {Op}, 0, Op, {0}, {}, /*Depth*/ 1,
-            /*HasVarMask*/ false, /*AllowVarMask*/ true, DAG, Subtarget))
+    if (SDValue Res = combineX86ShufflesRecursively(Op, DAG, Subtarget))
       return Res;
   }
 
@@ -36777,9 +36773,7 @@
   // Attempt to recursively combine an OR of shuffles.
   if (VT.isVector() && (VT.getScalarSizeInBits() % 8) == 0) {
     SDValue Op(N, 0);
-    if (SDValue Res = combineX86ShufflesRecursively(
-            {Op}, 0, Op, {0}, {}, /*Depth*/ 1,
-            /*HasVarMask*/ false, /*AllowVarMask*/ true, DAG, Subtarget))
+    if (SDValue Res = combineX86ShufflesRecursively(Op, DAG, Subtarget))
       return Res;
   }
 
@@ -39083,9 +39077,7 @@
   // Attempt to recursively combine a bitmask ANDNP with shuffles.
   if (VT.isVector() && (VT.getScalarSizeInBits() % 8) == 0) {
     SDValue Op(N, 0);
-    if (SDValue Res = combineX86ShufflesRecursively(
-            {Op}, 0, Op, {0}, {}, /*Depth*/ 1,
-            /*HasVarMask*/ false, /*AllowVarMask*/ true, DAG, Subtarget))
+    if (SDValue Res = combineX86ShufflesRecursively(Op, DAG, Subtarget))
       return Res;
   }