[X86][AVX512] createVariablePermute - Non-VLX targets can widen v4i64/v8f64 variable permutes to v8i64/v8f64

Permutes in the upper elements will be undefined, but they will be discarded anyway.

llvm-svn: 327238

1 files changed, 12 insertions, 2 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index eafa118897a..55c28c3b108 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -8048,9 +8048,19 @@ SDValue createVariablePermute(MVT VT, SDValue SrcVec, SDValue IndicesVec,
     break;
   case MVT::v4i64:
   case MVT::v4f64:
-    if (Subtarget.hasVLX())
+    if (Subtarget.hasAVX512()) {
+      if (!Subtarget.hasVLX()) {
+        MVT WidenSrcVT = MVT::getVectorVT(VT.getScalarType(), 8);
+        SrcVec = widenSubVector(WidenSrcVT, SrcVec, false, Subtarget, DAG,
+                                SDLoc(SrcVec));
+        IndicesVec = widenSubVector(MVT::v8i64, IndicesVec, false, Subtarget,
+                                    DAG, SDLoc(IndicesVec));
+        SDValue Res = createVariablePermute(WidenSrcVT, SrcVec, IndicesVec, DL,
+                                            DAG, Subtarget);
+        return extract256BitVector(Res, 0, DAG, DL);
+      }
       Opcode = X86ISD::VPERMV;
-    else if (Subtarget.hasXOP()) {
+    } else if (Subtarget.hasXOP()) {
       SrcVec = DAG.getBitcast(MVT::v4f64, SrcVec);
       SDValue LoLo =
           DAG.getVectorShuffle(MVT::v4f64, DL, SrcVec, SrcVec, {0, 1, 0, 1});