Fix 256-bit vpshuflw and vpshufhw immediate encoding to handle undefs in the lower half correctly. Missed in r155982.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156059 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 36 insertions, 21 deletions

diff --git a/lib/Target/X86/Utils/X86ShuffleDecode.cpp b/lib/Target/X86/Utils/X86ShuffleDecode.cpp
index a1f2424..f0d9467 100644
--- a/lib/Target/X86/Utils/X86ShuffleDecode.cpp
+++ b/lib/Target/X86/Utils/X86ShuffleDecode.cpp
@@ -82,8 +82,7 @@ void DecodePSHUFMask(EVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
 
 void DecodePSHUFHWMask(EVT VT, unsigned Imm,
                        SmallVectorImpl<int> &ShuffleMask) {
-  unsigned NumLanes = VT.getSizeInBits() / 128;
-  unsigned NumElts = 8 * NumLanes;
+  unsigned NumElts = VT.getVectorNumElements();
 
   for (unsigned l = 0; l != NumElts; l += 8) {
     unsigned NewImm = Imm;
@@ -99,8 +98,7 @@ void DecodePSHUFHWMask(EVT VT, unsigned Imm,
 
 void DecodePSHUFLWMask(EVT VT, unsigned Imm,
                        SmallVectorImpl<int> &ShuffleMask) {
-  unsigned NumLanes = VT.getSizeInBits() / 128;
-  unsigned NumElts = 8 * NumLanes;
+  unsigned NumElts = VT.getVectorNumElements();
 
   for (unsigned l = 0; l != NumElts; l += 8) {
     unsigned NewImm = Imm;
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index bdbdaf5..cacdb52 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -3904,9 +3904,8 @@ static unsigned getShuffleSHUFImmediate(ShuffleVectorSDNode *N) {
   for (unsigned i = 0; i != NumElts; ++i) {
     int Elt = N->getMaskElt(i);
     if (Elt < 0) continue;
-    Elt %= NumLaneElts;
-    unsigned ShAmt = i << Shift;
-    if (ShAmt >= 8) ShAmt -= 8;
+    Elt &= NumLaneElts - 1;
+    unsigned ShAmt = (i << Shift) % 8;
     Mask |= Elt << ShAmt;
   }
 
@@ -3916,30 +3915,48 @@ static unsigned getShuffleSHUFImmediate(ShuffleVectorSDNode *N) {
 /// getShufflePSHUFHWImmediate - Return the appropriate immediate to shuffle
 /// the specified VECTOR_SHUFFLE mask with the PSHUFHW instruction.
 static unsigned getShufflePSHUFHWImmediate(ShuffleVectorSDNode *N) {
+  EVT VT = N->getValueType(0);
+
+  assert((VT == MVT::v8i16 || VT == MVT::v16i16) &&
+         "Unsupported vector type for PSHUFHW");
+
+  unsigned NumElts = VT.getVectorNumElements();
+
   unsigned Mask = 0;
-  // 8 nodes, but we only care about the last 4.
-  for (unsigned i = 7; i >= 4; --i) {
-    int Val = N->getMaskElt(i);
-    if (Val >= 0)
-      Mask |= (Val - 4);
-    if (i != 4)
-      Mask <<= 2;
+  for (unsigned l = 0; l != NumElts; l += 8) {
+    // 8 nodes per lane, but we only care about the last 4.
+    for (unsigned i = 0; i < 4; ++i) {
+      int Elt = N->getMaskElt(l+i+4);
+      if (Elt < 0) continue;
+      Elt &= 0x3; // only 2-bits.
+      Mask |= Elt << (i * 2);
+    }
   }
+
   return Mask;
 }
 
 /// getShufflePSHUFLWImmediate - Return the appropriate immediate to shuffle
 /// the specified VECTOR_SHUFFLE mask with the PSHUFLW instruction.
 static unsigned getShufflePSHUFLWImmediate(ShuffleVectorSDNode *N) {
+  EVT VT = N->getValueType(0);
+
+  assert((VT == MVT::v8i16 || VT == MVT::v16i16) &&
+         "Unsupported vector type for PSHUFHW");
+
+  unsigned NumElts = VT.getVectorNumElements();
+
   unsigned Mask = 0;
-  // 8 nodes, but we only care about the first 4.
-  for (int i = 3; i >= 0; --i) {
-    int Val = N->getMaskElt(i);
-    if (Val >= 0)
-      Mask |= Val;
-    if (i != 0)
-      Mask <<= 2;
+  for (unsigned l = 0; l != NumElts; l += 8) {
+    // 8 nodes per lane, but we only care about the first 4.
+    for (unsigned i = 0; i < 4; ++i) {
+      int Elt = N->getMaskElt(l+i);
+      if (Elt < 0) continue;
+      Elt &= 0x3; // only 2-bits
+      Mask |= Elt << (i * 2);
+    }
   }
+
   return Mask;
 }