[llvm] d33ba1a - [X86][AVX] getFauxShuffleMask - don't widen shuffle inputs from INSERT_SUBVECTOR(X,SHUFFLE(Y,Z))

[Simon Pilgrim via llvm-commits]

Author: Simon Pilgrim
Date: 2020-05-31T13:19:18+01:00
New Revision: d33ba1aa0b505e3f4c55b382f171e8cbef6a1843

URL: https://github.com/llvm/llvm-project/commit/d33ba1aa0b505e3f4c55b382f171e8cbef6a1843
DIFF: https://github.com/llvm/llvm-project/commit/d33ba1aa0b505e3f4c55b382f171e8cbef6a1843.diff

LOG: [X86][AVX] getFauxShuffleMask - don't widen shuffle inputs from INSERT_SUBVECTOR(X,SHUFFLE(Y,Z))

Don't create nodes on the fly when decoding INSERT_SUBVECTOR as faux shuffles.

Added: 
    

Modified: 
    llvm/lib/Target/X86/X86ISelLowering.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index bcaf6298de33..95c9312cd772 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -7438,9 +7438,9 @@ static bool getFauxShuffleMask(SDValue N, const APInt &DemandedElts,
                                 SubMask, DAG, Depth + 1, ResolveKnownElts))
       return false;
 
-    // Shuffle inputs must be the same size as the subvector.
+    // Subvector shuffle inputs must not be larger than the subvector.
     if (llvm::any_of(SubInputs, [SubVT](SDValue Op) {
-          return SubVT.getSizeInBits() != Op.getValueSizeInBits();
+          return SubVT.getSizeInBits() > Op.getValueSizeInBits();
         }))
       return false;
 
@@ -7460,14 +7460,7 @@ static bool getFauxShuffleMask(SDValue N, const APInt &DemandedElts,
       }
     }
     Ops.push_back(Src);
-    for (SDValue &SubInput : SubInputs) {
-      EVT SubSVT = SubInput.getValueType().getScalarType();
-      EVT AltVT = EVT::getVectorVT(*DAG.getContext(), SubSVT,
-                                   NumSizeInBits / SubSVT.getSizeInBits());
-      Ops.push_back(DAG.getNode(ISD::INSERT_SUBVECTOR, SDLoc(N), AltVT,
-                                DAG.getUNDEF(AltVT), SubInput,
-                                DAG.getIntPtrConstant(0, SDLoc(N))));
-    }
+    Ops.append(SubInputs.begin(), SubInputs.end());
     for (int i = 0; i != (int)NumElts; ++i)
       Mask.push_back(i);
     for (int i = 0; i != (int)NumSubElts; ++i) {