1 files changed, 89 insertions, 26 deletions

diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 0fcc42d8da..f9a34e0e57 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -2758,68 +2758,130 @@ static SDValue LowerVSETCC(SDValue Op, SelectionDAG &DAG) {
 }
 
 /// isVMOVSplat - Check if the specified splat value corresponds to an immediate
-/// VMOV instruction, and if so, return the constant being splatted.
+/// VMOV instruction.  If so, return either the constant being splatted or the
+/// encoded value, depending on the DoEncode parameter.  The format of the
+/// encoded value is: bit12=Op, bits11-8=Cmode, bits7-0=Immediate.
 static SDValue isVMOVSplat(uint64_t SplatBits, uint64_t SplatUndef,
-                           unsigned SplatBitSize, SelectionDAG &DAG) {
+                           unsigned SplatBitSize, SelectionDAG &DAG,
+                           bool DoEncode) {
+  unsigned Op, Cmode, Imm;
+  EVT VT;
+
+  Op = 0;
   switch (SplatBitSize) {
   case 8:
-    // Any 1-byte value is OK.
+    // Any 1-byte value is OK.  Op=0, Cmode=1110.
     assert((SplatBits & ~0xff) == 0 && "one byte splat value is too big");
-    return DAG.getTargetConstant(SplatBits, MVT::i8);
+    Cmode = 0xe;
+    Imm = SplatBits;
+    VT = MVT::i8;
+    break;
 
   case 16:
     // NEON's 16-bit VMOV supports splat values where only one byte is nonzero.
-    if ((SplatBits & ~0xff) == 0 ||
-        (SplatBits & ~0xff00) == 0)
-      return DAG.getTargetConstant(SplatBits, MVT::i16);
-    break;
+    VT = MVT::i16;
+    if ((SplatBits & ~0xff) == 0) {
+      // Value = 0x00nn: Op=x, Cmode=100x.
+      Cmode = 0x8;
+      Imm = SplatBits;
+      break;
+    }
+    if ((SplatBits & ~0xff00) == 0) {
+      // Value = 0xnn00: Op=x, Cmode=101x.
+      Cmode = 0xa;
+      Imm = SplatBits >> 8;
+      break;
+    }
+    return SDValue();
 
   case 32:
     // NEON's 32-bit VMOV supports splat values where:
     // * only one byte is nonzero, or
     // * the least significant byte is 0xff and the second byte is nonzero, or
     // * the least significant 2 bytes are 0xff and the third is nonzero.
-    if ((SplatBits & ~0xff) == 0 ||
-        (SplatBits & ~0xff00) == 0 ||
-        (SplatBits & ~0xff0000) == 0 ||
-        (SplatBits & ~0xff000000) == 0)
-      return DAG.getTargetConstant(SplatBits, MVT::i32);
+    VT = MVT::i32;
+    if ((SplatBits & ~0xff) == 0) {
+      // Value = 0x000000nn: Op=x, Cmode=000x.
+      Cmode = 0;
+      Imm = SplatBits;
+      break;
+    }
+    if ((SplatBits & ~0xff00) == 0) {
+      // Value = 0x0000nn00: Op=x, Cmode=001x.
+      Cmode = 0x2;
+      Imm = SplatBits >> 8;
+      break;
+    }
+    if ((SplatBits & ~0xff0000) == 0) {
+      // Value = 0x00nn0000: Op=x, Cmode=010x.
+      Cmode = 0x4;
+      Imm = SplatBits >> 16;
+      break;
+    }
+    if ((SplatBits & ~0xff000000) == 0) {
+      // Value = 0xnn000000: Op=x, Cmode=011x.
+      Cmode = 0x6;
+      Imm = SplatBits >> 24;
+      break;
+    }
 
     if ((SplatBits & ~0xffff) == 0 &&
-        ((SplatBits | SplatUndef) & 0xff) == 0xff)
-      return DAG.getTargetConstant(SplatBits | 0xff, MVT::i32);
+        ((SplatBits | SplatUndef) & 0xff) == 0xff) {
+      // Value = 0x0000nnff: Op=x, Cmode=1100.
+      Cmode = 0xc;
+      Imm = SplatBits >> 8;
+      SplatBits |= 0xff;
+      break;
+    }
 
     if ((SplatBits & ~0xffffff) == 0 &&
-        ((SplatBits | SplatUndef) & 0xffff) == 0xffff)
-      return DAG.getTargetConstant(SplatBits | 0xffff, MVT::i32);
+        ((SplatBits | SplatUndef) & 0xffff) == 0xffff) {
+      // Value = 0x00nnffff: Op=x, Cmode=1101.
+      Cmode = 0xd;
+      Imm = SplatBits >> 16;
+      SplatBits |= 0xffff;
+      break;
+    }
 
     // Note: there are a few 32-bit splat values (specifically: 00ffff00,
     // ff000000, ff0000ff, and ffff00ff) that are valid for VMOV.I64 but not
     // VMOV.I32.  A (very) minor optimization would be to replicate the value
     // and fall through here to test for a valid 64-bit splat.  But, then the
     // caller would also need to check and handle the change in size.
-    break;
+    return SDValue();
 
   case 64: {
     // NEON has a 64-bit VMOV splat where each byte is either 0 or 0xff.
     uint64_t BitMask = 0xff;
     uint64_t Val = 0;
+    unsigned ImmMask = 1;
+    Imm = 0;
     for (int ByteNum = 0; ByteNum < 8; ++ByteNum) {
-      if (((SplatBits | SplatUndef) & BitMask) == BitMask)
+      if (((SplatBits | SplatUndef) & BitMask) == BitMask) {
         Val |= BitMask;
-      else if ((SplatBits & BitMask) != 0)
+        Imm |= ImmMask;
+      } else if ((SplatBits & BitMask) != 0) {
         return SDValue();
+      }
       BitMask <<= 8;
+      ImmMask <<= 1;
     }
-    return DAG.getTargetConstant(Val, MVT::i64);
+    // Op=1, Cmode=1110.
+    Op = 1;
+    Cmode = 0xe;
+    SplatBits = Val;
+    VT = MVT::i64;
+    break;
   }
 
   default:
-    llvm_unreachable("unexpected size for isVMOVSplat");
-    break;
+    llvm_unreachable("unexpected size for EncodeNEONModImm");
+    return SDValue();
   }
 
-  return SDValue();
+  if (DoEncode)
+    return DAG.getTargetConstant((Op << 12) | (Cmode << 8) | Imm, MVT::i32);
+  return DAG.getTargetConstant(SplatBits, VT);
 }
 
 /// getVMOVImm - If this is a build_vector of constants which can be
@@ -2839,7 +2901,7 @@ SDValue ARM::getVMOVImm(SDNode *N, unsigned ByteSize, SelectionDAG &DAG) {
     return SDValue();
 
   return isVMOVSplat(SplatBits.getZExtValue(), SplatUndef.getZExtValue(),
-                     SplatBitSize, DAG);
+                     SplatBitSize, DAG, true);
 }
 
 static bool isVEXTMask(const SmallVectorImpl<int> &M, EVT VT,
@@ -3080,7 +3142,8 @@ static SDValue LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG) {
   if (BVN->isConstantSplat(SplatBits, SplatUndef, SplatBitSize, HasAnyUndefs)) {
     if (SplatBitSize <= 64) {
       SDValue Val = isVMOVSplat(SplatBits.getZExtValue(),
-                                SplatUndef.getZExtValue(), SplatBitSize, DAG);
+                                SplatUndef.getZExtValue(), SplatBitSize, DAG,
+                                false);
       if (Val.getNode())
         return BuildSplat(Val, VT, DAG, dl);
     }