Canonicalize splats as build_vectors (PR22283)

This is a follow-on patch to:
http://reviews.llvm.org/D7093

That patch canonicalized constant splats as build_vectors,
and this patch removes the constant check so we can canonicalize
all splats as build_vectors.

This fixes the 2nd test case in PR22283:
http://llvm.org/bugs/show_bug.cgi?id=22283

The unfortunate code duplication between SelectionDAG and DAGCombiner
is discussed in the earlier patch review. At least this patch is just
removing code...

This improves an existing x86 AVX test and changes codegen in an ARM test.

Differential Revision: http://reviews.llvm.org/D7389

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229511 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 92164e925435612952bd9631b330d8167f834920..69efae738afbf9dfaa3c8a72c9d18f26e84b5b17 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -11749,20 +11749,17 @@ SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) {
       if (AllSame)
         return N0;
 
-      // If the splatted element is a constant, just build the vector out of
-      // constants directly.
+      // Canonicalize any other splat as a build_vector.
       const SDValue &Splatted = V->getOperand(SVN->getSplatIndex());
-      if (isa<ConstantSDNode>(Splatted) || isa<ConstantFPSDNode>(Splatted)) {
-        SmallVector<SDValue, 8> Ops(NumElts, Splatted);
-        SDValue NewBV = DAG.getNode(ISD::BUILD_VECTOR, SDLoc(N),
-          V->getValueType(0), Ops);
-
-        // We may have jumped through bitcasts, so the type of the
-        // BUILD_VECTOR may not match the type of the shuffle.
-        if (V->getValueType(0) != VT)
-           NewBV = DAG.getNode(ISD::BITCAST, SDLoc(N), VT, NewBV);
-        return NewBV;
-      }
+      SmallVector<SDValue, 8> Ops(NumElts, Splatted);
+      SDValue NewBV = DAG.getNode(ISD::BUILD_VECTOR, SDLoc(N),
+                                  V->getValueType(0), Ops);
+
+      // We may have jumped through bitcasts, so the type of the
+      // BUILD_VECTOR may not match the type of the shuffle.
+      if (V->getValueType(0) != VT)
+          NewBV = DAG.getNode(ISD::BITCAST, SDLoc(N), VT, NewBV);
+      return NewBV;
     }
   }
 

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 1e0e196389dc0cae27ec731174991707fe9687e3..9466f4dd060a2dcb62c3eb64ed04d990084d3514 100644 (file)
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1581,22 +1581,19 @@ SDValue SelectionDAG::getVectorShuffle(EVT VT, SDLoc dl, SDValue N1,
             return N1;
       }
 
-      // If the shuffle itself creates a constant splat, build the vector
-      // directly.
+      // If the shuffle itself creates a splat, build the vector directly.
       if (AllSame && SameNumElts) {
-         const SDValue &Splatted = BV->getOperand(MaskVec[0]);
-         if (isa<ConstantSDNode>(Splatted) || isa<ConstantFPSDNode>(Splatted)) {
-           SmallVector<SDValue, 8> Ops(NElts, Splatted);
-
-           SDValue NewBV =
-               getNode(ISD::BUILD_VECTOR, dl, BV->getValueType(0), Ops);
-
-           // We may have jumped through bitcasts, so the type of the
-           // BUILD_VECTOR may not match the type of the shuffle.
-           if (BV->getValueType(0) != VT)
-             NewBV = getNode(ISD::BITCAST, dl, VT, NewBV);
-           return NewBV;
-         }
+        const SDValue &Splatted = BV->getOperand(MaskVec[0]);
+        SmallVector<SDValue, 8> Ops(NElts, Splatted);
+
+        EVT BuildVT = BV->getValueType(0);
+        SDValue NewBV = getNode(ISD::BUILD_VECTOR, dl, BuildVT, Ops);
+
+        // We may have jumped through bitcasts, so the type of the
+        // BUILD_VECTOR may not match the type of the shuffle.
+        if (BuildVT != VT)
+          NewBV = getNode(ISD::BITCAST, dl, VT, NewBV);
+        return NewBV;
       }
     }
   }

diff --git a/test/CodeGen/ARM/vdup.ll b/test/CodeGen/ARM/vdup.ll
index 89f355c68751ba59e8d4b617c3829dc930dbfb46..6f8b3dda9cd077ac56db61b61d8d6aa6b39bdad4 100644 (file)
--- a/test/CodeGen/ARM/vdup.ll
+++ b/test/CodeGen/ARM/vdup.ll
@@ -347,17 +347,17 @@ define <2 x float> @check_spr_splat2(<2 x float> %p, i16 %q) {
 
 define <4 x float> @check_spr_splat4(<4 x float> %p, i16 %q) {
 ;CHECK-LABEL: check_spr_splat4:
-;CHECK: vdup.32 q
+;CHECK: vld1.16
   %conv = sitofp i16 %q to float
   %splat.splatinsert = insertelement <4 x float> undef, float %conv, i32 0
   %splat.splat = shufflevector <4 x float> %splat.splatinsert, <4 x float> undef, <4 x i32> zeroinitializer
   %sub = fsub <4 x float> %splat.splat, %p
   ret <4 x float> %sub
 }
-
+; Same codegen as above test; scalar is splatted using vld1, so shuffle index is irrelevant.
 define <4 x float> @check_spr_splat4_lane1(<4 x float> %p, i16 %q) {
 ;CHECK-LABEL: check_spr_splat4_lane1:
-;CHECK: vdup.32 q{{.*}}, d{{.*}}[1]
+;CHECK: vld1.16
   %conv = sitofp i16 %q to float
   %splat.splatinsert = insertelement <4 x float> undef, float %conv, i32 1
   %splat.splat = shufflevector <4 x float> %splat.splatinsert, <4 x float> undef, <4 x i32> <i32 1, i32 1, i32 1, i32 1>

diff --git a/test/CodeGen/X86/vector-shuffle-256-v4.ll b/test/CodeGen/X86/vector-shuffle-256-v4.ll
index 7b8c1d62fc43289e38874120fb08b5f05843afdf..bb08b94156652d76938aaba9b0809e803ed463e5 100644 (file)
--- a/test/CodeGen/X86/vector-shuffle-256-v4.ll
+++ b/test/CodeGen/X86/vector-shuffle-256-v4.ll
@@ -885,8 +885,7 @@ define <4 x double> @splat_mem_v4f64(double* %ptr) {
 define <4 x i64> @splat_mem_v4i64(i64* %ptr) {
 ; AVX1-LABEL: splat_mem_v4i64:
 ; AVX1:       # BB#0:
-; AVX1-NEXT:    vmovddup {{.*#+}} xmm0 = mem[0,0]
-; AVX1-NEXT:    vinsertf128 $1, %xmm0, %ymm0, %ymm0
+; AVX1-NEXT:    vbroadcastsd (%rdi), %ymm0
 ; AVX1-NEXT:    retq
 ;
 ; AVX2-LABEL: splat_mem_v4i64: