[x86] Switch an if which is trivially true to an assert. NFC

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229669 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index f9d305cc6e9e7935e8c90af61ef007bb267926c3..1a88676a910d762f9013dceaca5f7cc4af562a92 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -8618,26 +8618,26 @@ static SDValue lowerV2I64VectorShuffle(SDValue Op, SDValue V1, SDValue V2,
         DAG.getNode(X86ISD::PSHUFD, SDLoc(Op), MVT::v4i32, V1,
                     getV4X86ShuffleImm8ForMask(WidenedMask, DAG)));
   }
+  assert((Mask[0] >= 2) + (Mask[1] >= 2) == 1 &&
+         "Canonicalization ensures we only see shuffles with two inputs.");
 
   // Try to use shift instructions.
   if (SDValue Shift =
           lowerVectorShuffleAsShift(DL, MVT::v2i64, V1, V2, Mask, DAG))
     return Shift;
 
-  // If we have a single input from V2 insert that into V1 if we can do so
-  // cheaply.
-  if ((Mask[0] >= 2) + (Mask[1] >= 2) == 1) {
-    if (SDValue Insertion = lowerVectorShuffleAsElementInsertion(
-            MVT::v2i64, DL, V1, V2, Mask, Subtarget, DAG))
-      return Insertion;
-    // Try inverting the insertion since for v2 masks it is easy to do and we
-    // can't reliably sort the mask one way or the other.
-    int InverseMask[2] = {Mask[0] < 0 ? -1 : (Mask[0] ^ 2),
-                          Mask[1] < 0 ? -1 : (Mask[1] ^ 2)};
-    if (SDValue Insertion = lowerVectorShuffleAsElementInsertion(
-            MVT::v2i64, DL, V2, V1, InverseMask, Subtarget, DAG))
-      return Insertion;
-  }
+  // When loading a scalar and then shuffling it into a vector we can often do
+  // the insertion cheaply.
+  if (SDValue Insertion = lowerVectorShuffleAsElementInsertion(
+          MVT::v2i64, DL, V1, V2, Mask, Subtarget, DAG))
+    return Insertion;
+  // Try inverting the insertion since for v2 masks it is easy to do and we
+  // can't reliably sort the mask one way or the other.
+  int InverseMask[2] = {Mask[0] < 0 ? -1 : (Mask[0] ^ 2),
+                        Mask[1] < 0 ? -1 : (Mask[1] ^ 2)};
+  if (SDValue Insertion = lowerVectorShuffleAsElementInsertion(
+          MVT::v2i64, DL, V2, V1, InverseMask, Subtarget, DAG))
+    return Insertion;
 
   // We have different paths for blend lowering, but they all must use the
   // *exact* same predicate.