[PATCH] Optimize shufflevector that copies an i64/f64 and zeros the rest.

[Filipe Cabecinhas]

Merged the if statement into the previous statement.

RewriteAsNarrowerShuffle will now return its argument if it's a v2?64
vector.

http://reviews.llvm.org/D3518

Files:
  lib/Target/X86/X86ISelLowering.cpp
  test/CodeGen/X86/avx-shuffle.ll
  test/CodeGen/X86/sse2.ll

Index: lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- lib/Target/X86/X86ISelLowering.cpp
+++ lib/Target/X86/X86ISelLowering.cpp
@@ -6879,6 +6879,9 @@
   unsigned Scale;
   switch (VT.SimpleTy) {
   default: llvm_unreachable("Unexpected!");
+  case MVT::v2i64:
+  case MVT::v2f64:
+           return SDValue(SVOp, 0);
   case MVT::v4f32:  NewVT = MVT::v2f64; Scale = 2; break;
   case MVT::v4i32:  NewVT = MVT::v2i64; Scale = 2; break;
   case MVT::v8i16:  NewVT = MVT::v4i32; Scale = 2; break;
@@ -7480,9 +7483,8 @@
                      DAG.getNode(X86ISD::VZEXT, DL, NVT, V1));
 }
 
-static SDValue
-NormalizeVectorShuffle(SDValue Op, const X86Subtarget *Subtarget,
-                       SelectionDAG &DAG) {
+static SDValue NormalizeVectorShuffle(SDValue Op, const X86Subtarget *Subtarget,
+                                      SelectionDAG &DAG) {
   ShuffleVectorSDNode *SVOp = cast<ShuffleVectorSDNode>(Op);
   MVT VT = Op.getSimpleValueType();
   SDLoc dl(Op);
@@ -7507,31 +7509,30 @@
 
   // If the shuffle can be profitably rewritten as a narrower shuffle, then
   // do it!
-  if (VT == MVT::v8i16  || VT == MVT::v16i8 ||
-      VT == MVT::v16i16 || VT == MVT::v32i8) {
+  if (VT == MVT::v8i16 || VT == MVT::v16i8 || VT == MVT::v16i16 ||
+      VT == MVT::v32i8) {
     SDValue NewOp = RewriteAsNarrowerShuffle(SVOp, DAG);
     if (NewOp.getNode())
       return DAG.getNode(ISD::BITCAST, dl, VT, NewOp);
-  } else if ((VT == MVT::v4i32 ||
-             (VT == MVT::v4f32 && Subtarget->hasSSE2()))) {
+  } else if (VT == MVT::v4i32 ||
+             (VT.is128BitVector() && Subtarget->hasSSE2())) {
     // FIXME: Figure out a cleaner way to do this.
-    // Try to make use of movq to zero out the top part.
     if (ISD::isBuildVectorAllZeros(V2.getNode())) {
       SDValue NewOp = RewriteAsNarrowerShuffle(SVOp, DAG);
       if (NewOp.getNode()) {
         MVT NewVT = NewOp.getSimpleValueType();
         if (isCommutedMOVLMask(cast<ShuffleVectorSDNode>(NewOp)->getMask(),
                                NewVT, true, false))
-          return getVZextMovL(VT, NewVT, NewOp.getOperand(0),
-                              DAG, Subtarget, dl);
+          return getVZextMovL(VT, NewVT, NewOp.getOperand(0), DAG, Subtarget,
+                              dl);
       }
     } else if (ISD::isBuildVectorAllZeros(V1.getNode())) {
       SDValue NewOp = RewriteAsNarrowerShuffle(SVOp, DAG);
       if (NewOp.getNode()) {
         MVT NewVT = NewOp.getSimpleValueType();
         if (isMOVLMask(cast<ShuffleVectorSDNode>(NewOp)->getMask(), NewVT))
-          return getVZextMovL(VT, NewVT, NewOp.getOperand(1),
-                              DAG, Subtarget, dl);
+          return getVZextMovL(VT, NewVT, NewOp.getOperand(1), DAG, Subtarget,
+                              dl);
       }
     }
   }
Index: test/CodeGen/X86/avx-shuffle.ll
===================================================================
--- test/CodeGen/X86/avx-shuffle.ll
+++ test/CodeGen/X86/avx-shuffle.ll
@@ -306,3 +306,11 @@
   store <3 x double> %a1, <3 x double>* undef, align 1
   ret void
 }
+
+define <2 x i64> @test_insert_64_zext(<2 x i64> %i) {
+; CHECK-LABEL: test_insert_64_zext
+; CHECK-NOT: xor
+; CHECK: vmovq
+  %1 = shufflevector <2 x i64> %i, <2 x i64> <i64 0, i64 undef>, <2 x i32> <i32 0, i32 2>
+  ret <2 x i64> %1
+}
Index: test/CodeGen/X86/sse2.ll
===================================================================
--- test/CodeGen/X86/sse2.ll
+++ test/CodeGen/X86/sse2.ll
@@ -221,3 +221,11 @@
  %double2float.i = fptrunc <4 x double> %0 to <4 x float>
  ret <4 x float> %double2float.i
 }
+
+define <2 x i64> @test_insert_64_zext(<2 x i64> %i) {
+; CHECK-LABEL: test_insert_64_zext
+; CHECK-NOT: xor
+; CHECK: movq
+  %1 = shufflevector <2 x i64> %i, <2 x i64> <i64 0, i64 undef>, <2 x i32> <i32 0, i32 2>
+  ret <2 x i64> %1
+}
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D3518.9196.patch
Type: text/x-patch
Size: 3896 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20140508/a8f14a89/attachment.bin>