From 3a2363c7974ab12c29a200686fcf57ca29936c07 Mon Sep 17 00:00:00 2001
From: David Zarzycki <dave@znu.io>
Date: Fri, 18 Oct 2019 03:45:52 +0000
Subject: [PATCH] [X86] Emit KTEST when possible

https://reviews.llvm.org/D69111

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375197 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86ISelLowering.cpp | 31 ++++++++++++++++++++++--------
 test/CodeGen/X86/avx512-mask-op.ll | 12 ++++++------
 2 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index c43c464526d..0e6205a55cc 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/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.
diff --git a/test/CodeGen/X86/avx512-mask-op.ll b/test/CodeGen/X86/avx512-mask-op.ll
index 8c86d957d4c..b9724f8c4d6 100644
--- a/test/CodeGen/X86/avx512-mask-op.ll
+++ b/test/CodeGen/X86/avx512-mask-op.ll
@@ -2027,8 +2027,8 @@ define void @ktest_1(<8 x double> %in, double * %base) {
 ; SKX:       ## %bb.0:
 ; SKX-NEXT:    vcmpgtpd (%rdi), %zmm0, %k1
 ; SKX-NEXT:    vmovupd 8(%rdi), %zmm1 {%k1} {z}
-; SKX-NEXT:    vcmpltpd %zmm1, %zmm0, %k0 {%k1}
-; SKX-NEXT:    kortestb %k0, %k0
+; SKX-NEXT:    vcmpltpd %zmm1, %zmm0, %k0
+; SKX-NEXT:    ktestb %k0, %k1
 ; SKX-NEXT:    je LBB43_2
 ; SKX-NEXT:  ## %bb.1: ## %L1
 ; SKX-NEXT:    vmovapd %zmm0, (%rdi)
@@ -2060,8 +2060,8 @@ define void @ktest_1(<8 x double> %in, double * %base) {
 ; AVX512DQ:       ## %bb.0:
 ; AVX512DQ-NEXT:    vcmpgtpd (%rdi), %zmm0, %k1
 ; AVX512DQ-NEXT:    vmovupd 8(%rdi), %zmm1 {%k1} {z}
-; AVX512DQ-NEXT:    vcmpltpd %zmm1, %zmm0, %k0 {%k1}
-; AVX512DQ-NEXT:    kortestb %k0, %k0
+; AVX512DQ-NEXT:    vcmpltpd %zmm1, %zmm0, %k0
+; AVX512DQ-NEXT:    ktestb %k0, %k1
 ; AVX512DQ-NEXT:    je LBB43_2
 ; AVX512DQ-NEXT:  ## %bb.1: ## %L1
 ; AVX512DQ-NEXT:    vmovapd %zmm0, (%rdi)
@@ -2077,8 +2077,8 @@ define void @ktest_1(<8 x double> %in, double * %base) {
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %eax
 ; X86-NEXT:    vcmpgtpd (%eax), %zmm0, %k1
 ; X86-NEXT:    vmovupd 8(%eax), %zmm1 {%k1} {z}
-; X86-NEXT:    vcmpltpd %zmm1, %zmm0, %k0 {%k1}
-; X86-NEXT:    kortestb %k0, %k0
+; X86-NEXT:    vcmpltpd %zmm1, %zmm0, %k0
+; X86-NEXT:    ktestb %k0, %k1
 ; X86-NEXT:    je LBB43_2
 ; X86-NEXT:  ## %bb.1: ## %L1
 ; X86-NEXT:    vmovapd %zmm0, (%eax)
-- 
2.50.1