[X86][SSE] Add support for combining AND bitmasks to shuffles.

llvm-svn: 288365

1 files changed, 11 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 661d28156ba..85766c9f0cc 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -29889,6 +29889,17 @@ static SDValue combineAnd(SDNode *N, SelectionDAG &DAG,
   SDValue N1 = N->getOperand(1);
   SDLoc DL(N);
 
+  // Attempt to recursively combine a bitmask AND with shuffles.
+  if (VT.isVector() && (VT.getScalarSizeInBits() % 8) == 0) {
+    SDValue Op(N, 0);
+    SmallVector<int, 1> NonceMask; // Just a placeholder.
+    NonceMask.push_back(0);
+    if (combineX86ShufflesRecursively({Op}, 0, Op, NonceMask,
+                                      /*Depth*/ 1, /*HasPSHUFB*/ false, DAG,
+                                      DCI, Subtarget))
+      return SDValue(); // This routine will use CombineTo to replace N.
+  }
+
   // Create BEXTR instructions
   // BEXTR is ((X >> imm) & (2**size-1))
   if (VT != MVT::i32 && VT != MVT::i64)