From 18b73a655bb611534165fe40e417fde89684f776 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev@redking.me.uk>
Date: Sun, 3 Feb 2019 16:10:18 +0000
Subject: [PATCH] [X86][AVX] Support shuffle combining for VPMOVZX with smaller
 vector sources

llvm-svn: 352997
---
 llvm/lib/Target/X86/X86ISelLowering.cpp        | 18 ++++++++++++-----
 llvm/test/CodeGen/X86/vector-shuffle-256-v8.ll | 27 ++++++++++++++++++--------
 2 files changed, 32 insertions(+), 13 deletions(-)

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 9ea3c64..dbc4947 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -6775,13 +6775,21 @@ static bool getFauxShuffleMask(SDValue N, SmallVectorImpl<int> &Mask,
   }
   case ISD::ZERO_EXTEND_VECTOR_INREG:
   case ISD::ZERO_EXTEND: {
-    // TODO - add support for VPMOVZX with smaller input vector types.
     SDValue Src = N.getOperand(0);
     MVT SrcVT = Src.getSimpleValueType();
-    if (NumSizeInBits != SrcVT.getSizeInBits())
-      break;
-    DecodeZeroExtendMask(SrcVT.getScalarSizeInBits(), NumBitsPerElt, NumElts,
-                         Mask);
+    unsigned NumSrcBitsPerElt = SrcVT.getScalarSizeInBits();
+    DecodeZeroExtendMask(NumSrcBitsPerElt, NumBitsPerElt, NumElts, Mask);
+
+    if (NumSizeInBits != SrcVT.getSizeInBits()) {
+      assert((NumSizeInBits % SrcVT.getSizeInBits()) == 0 &&
+             "Illegal zero-extension type");
+      SrcVT = MVT::getVectorVT(SrcVT.getScalarType(),
+                               NumSizeInBits / NumSrcBitsPerElt);
+      Src = DAG.getNode(ISD::INSERT_SUBVECTOR, SDLoc(N), SrcVT,
+                        DAG.getUNDEF(SrcVT), Src,
+                        DAG.getIntPtrConstant(0, SDLoc(N)));
+    }
+
     Ops.push_back(Src);
     return true;
   }
diff --git a/llvm/test/CodeGen/X86/vector-shuffle-256-v8.ll b/llvm/test/CodeGen/X86/vector-shuffle-256-v8.ll
index 651cb73..8d13670 100644
--- a/llvm/test/CodeGen/X86/vector-shuffle-256-v8.ll
+++ b/llvm/test/CodeGen/X86/vector-shuffle-256-v8.ll
@@ -1526,9 +1526,8 @@ define <8 x i32> @shuffle_v8i32_08192a3b(<8 x i32> %a, <8 x i32> %b) {
 ;
 ; AVX512VL-LABEL: shuffle_v8i32_08192a3b:
 ; AVX512VL:       # %bb.0:
-; AVX512VL-NEXT:    vpmovzxdq {{.*#+}} ymm2 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero
-; AVX512VL-NEXT:    vmovdqa {{.*#+}} ymm0 = [0,8,2,9,4,10,6,11]
-; AVX512VL-NEXT:    vpermi2d %ymm1, %ymm2, %ymm0
+; AVX512VL-NEXT:    vmovdqa {{.*#+}} ymm2 = [0,8,1,9,2,10,3,11]
+; AVX512VL-NEXT:    vpermt2d %ymm1, %ymm2, %ymm0
 ; AVX512VL-NEXT:    retq
   %shuffle = shufflevector <8 x i32> %a, <8 x i32> %b, <8 x i32> <i32 0, i32 8, i32 1, i32 9, i32 2, i32 10, i32 3, i32 11>
   ret <8 x i32> %shuffle
@@ -1572,11 +1571,23 @@ define <8 x i32> @shuffle_v8i32_091b2d3f(<8 x i32> %a, <8 x i32> %b) {
 ; AVX1-NEXT:    vblendps {{.*#+}} ymm0 = ymm0[0],ymm1[1],ymm0[2],ymm1[3],ymm0[4],ymm1[5],ymm0[6],ymm1[7]
 ; AVX1-NEXT:    retq
 ;
-; AVX2OR512VL-LABEL: shuffle_v8i32_091b2d3f:
-; AVX2OR512VL:       # %bb.0:
-; AVX2OR512VL-NEXT:    vpmovzxdq {{.*#+}} ymm0 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero
-; AVX2OR512VL-NEXT:    vpblendd {{.*#+}} ymm0 = ymm0[0],ymm1[1],ymm0[2],ymm1[3],ymm0[4],ymm1[5],ymm0[6],ymm1[7]
-; AVX2OR512VL-NEXT:    retq
+; AVX2-LABEL: shuffle_v8i32_091b2d3f:
+; AVX2:       # %bb.0:
+; AVX2-NEXT:    vpmovzxdq {{.*#+}} ymm0 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero
+; AVX2-NEXT:    vpblendd {{.*#+}} ymm0 = ymm0[0],ymm1[1],ymm0[2],ymm1[3],ymm0[4],ymm1[5],ymm0[6],ymm1[7]
+; AVX2-NEXT:    retq
+;
+; AVX512VL-SLOW-LABEL: shuffle_v8i32_091b2d3f:
+; AVX512VL-SLOW:       # %bb.0:
+; AVX512VL-SLOW-NEXT:    vpmovzxdq {{.*#+}} ymm0 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero
+; AVX512VL-SLOW-NEXT:    vpblendd {{.*#+}} ymm0 = ymm0[0],ymm1[1],ymm0[2],ymm1[3],ymm0[4],ymm1[5],ymm0[6],ymm1[7]
+; AVX512VL-SLOW-NEXT:    retq
+;
+; AVX512VL-FAST-LABEL: shuffle_v8i32_091b2d3f:
+; AVX512VL-FAST:       # %bb.0:
+; AVX512VL-FAST-NEXT:    vmovdqa {{.*#+}} ymm2 = [0,9,1,11,2,13,3,15]
+; AVX512VL-FAST-NEXT:    vpermt2d %ymm1, %ymm2, %ymm0
+; AVX512VL-FAST-NEXT:    retq
   %shuffle = shufflevector <8 x i32> %a, <8 x i32> %b, <8 x i32> <i32 0, i32 9, i32 1, i32 11, i32 2, i32 13, i32 3, i32 15>
   ret <8 x i32> %shuffle
 }
-- 
2.7.4