[X86] Emit KTEST when possible

https://reviews.llvm.org/D69111

llvm-svn: 375197

1 files changed, 23 insertions, 8 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index c43c464526d..0e6205a55cc 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -20923,11 +20923,11 @@ static SDValue LowerVSETCC(SDValue Op, const X86Subtarget &Subtarget,
   return Result;
 }
 
-// Try to select this as a KORTEST+SETCC if possible.
-static SDValue EmitKORTEST(SDValue Op0, SDValue Op1, ISD::CondCode CC,
-                           const SDLoc &dl, SelectionDAG &DAG,
-                           const X86Subtarget &Subtarget,
-                           SDValue &X86CC) {
+// Try to select this as a KORTEST+SETCC or KTEST+SETCC if possible.
+static SDValue EmitAVX512Test(SDValue Op0, SDValue Op1, ISD::CondCode CC,
+                              const SDLoc &dl, SelectionDAG &DAG,
+                              const X86Subtarget &Subtarget,
+                              SDValue &X86CC) {
   // Only support equality comparisons.
   if (CC != ISD::SETEQ && CC != ISD::SETNE)
     return SDValue();
@@ -20952,6 +20952,21 @@ static SDValue EmitKORTEST(SDValue Op0, SDValue Op1, ISD::CondCode CC,
   } else
     return SDValue();
 
+  // If the input is an AND, we can combine it's operands into the KTEST.
+  bool KTestable = false;
+  if (Subtarget.hasDQI() && (VT == MVT::v8i1 || VT == MVT::v16i1))
+    KTestable = true;
+  if (Subtarget.hasBWI() && (VT == MVT::v32i1 || VT == MVT::v64i1))
+    KTestable = true;
+  if (!isNullConstant(Op1))
+    KTestable = false;
+  if (KTestable && Op0.getOpcode() == ISD::AND && Op0.hasOneUse()) {
+    SDValue LHS = Op0.getOperand(0);
+    SDValue RHS = Op0.getOperand(1);
+    X86CC = DAG.getTargetConstant(X86Cond, dl, MVT::i8);
+    return DAG.getNode(X86ISD::KTEST, dl, MVT::i32, LHS, RHS);
+  }
+
   // If the input is an OR, we can combine it's operands into the KORTEST.
   SDValue LHS = Op0;
   SDValue RHS = Op0;
@@ -20988,9 +21003,9 @@ SDValue X86TargetLowering::emitFlagsForSetcc(SDValue Op0, SDValue Op1,
       return PTEST;
   }
 
-  // Try to lower using KORTEST.
-  if (SDValue KORTEST = EmitKORTEST(Op0, Op1, CC, dl, DAG, Subtarget, X86CC))
-    return KORTEST;
+  // Try to lower using KORTEST or KTEST.
+  if (SDValue Test = EmitAVX512Test(Op0, Op1, CC, dl, DAG, Subtarget, X86CC))
+    return Test;
 
   // Look for X == 0, X == 1, X != 0, or X != 1.  We can simplify some forms of
   // these.