Add ARM patterns to match EXTRACT_SUBVECTOR nodes.

Also fix an off-by-one in SelectionDAGBuilder that was preventing shuffle
vectors from being translated to EXTRACT_SUBVECTOR.
Patch by Tim Northover.

The test changes are needed to keep those spill-q tests from testing aligned
spills and restores.  If the only aligned stack objects are spill slots, we
no longer realign the stack frame.  Prior to this patch, an EXTRACT_SUBVECTOR
was legalized by loading from the stack, which created an aligned frame index.
Now, however, there is nothing except the spill slot in the stack frame, so
I added an aligned alloca.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122995 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 30 insertions, 4 deletions

diff --git a/include/llvm/Target/TargetSelectionDAG.td b/include/llvm/Target/TargetSelectionDAG.td
index 92ceee5bfb..37ebc12e5b 100644
--- a/include/llvm/Target/TargetSelectionDAG.td
+++ b/include/llvm/Target/TargetSelectionDAG.td
@@ -421,6 +421,9 @@ def scalar_to_vector : SDNode<"ISD::SCALAR_TO_VECTOR", SDTypeProfile<1, 1, []>,
                               []>;
 def vector_extract : SDNode<"ISD::EXTRACT_VECTOR_ELT",
     SDTypeProfile<1, 2, [SDTCisPtrTy<2>]>, []>;
+def vector_extract_subvec : SDNode<"ISD::EXTRACT_SUBVECTOR",
+    SDTypeProfile<1, 2, [SDTCisInt<2>, SDTCisVec<1>, SDTCisVec<0>]>, 
+    []>;
 def vector_insert : SDNode<"ISD::INSERT_VECTOR_ELT",
     SDTypeProfile<1, 3, [SDTCisSameAs<0, 1>, SDTCisPtrTy<3>]>, []>;
 
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 88490b3120..2167523f23 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -2745,7 +2745,7 @@ void SelectionDAGBuilder::visitShuffleVector(const User &I) {
         } else {
           StartIdx[Input] = (MinRange[Input]/MaskNumElts)*MaskNumElts;
           if (MaxRange[Input] - StartIdx[Input] < (int)MaskNumElts &&
-              StartIdx[Input] + MaskNumElts < SrcNumElts)
+              StartIdx[Input] + MaskNumElts <= SrcNumElts)
             RangeUse[Input] = 1; // Extract from a multiple of the mask length.
         }
       }
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index f50eac523f..b4432d5236 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -94,7 +94,7 @@ void ARMTargetLowering::addTypeForNEON(EVT VT, EVT PromotedLdStVT,
   setOperationAction(ISD::BUILD_VECTOR, VT.getSimpleVT(), Custom);
   setOperationAction(ISD::VECTOR_SHUFFLE, VT.getSimpleVT(), Custom);
   setOperationAction(ISD::CONCAT_VECTORS, VT.getSimpleVT(), Legal);
-  setOperationAction(ISD::EXTRACT_SUBVECTOR, VT.getSimpleVT(), Expand);
+  setOperationAction(ISD::EXTRACT_SUBVECTOR, VT.getSimpleVT(), Legal);
   setOperationAction(ISD::SELECT, VT.getSimpleVT(), Expand);
   setOperationAction(ISD::SELECT_CC, VT.getSimpleVT(), Expand);
   if (VT.isInteger()) {
diff --git a/lib/Target/ARM/ARMInstrNEON.td b/lib/Target/ARM/ARMInstrNEON.td
index e307105a5c..20437963f6 100644
--- a/lib/Target/ARM/ARMInstrNEON.td
+++ b/lib/Target/ARM/ARMInstrNEON.td
@@ -4530,6 +4530,23 @@ def VREV16q8  : VREV16Q<0b00, "vrev16", "8", v16i8>;
 
 // Other Vector Shuffles.
 
+//  Aligned extractions: really just dropping registers
+
+class AlignedVEXTq<ValueType DestTy, ValueType SrcTy, SDNodeXForm LaneCVT>
+      : Pat<(DestTy (vector_extract_subvec (SrcTy QPR:$src), (i32 imm:$start))),
+             (EXTRACT_SUBREG (SrcTy QPR:$src), (LaneCVT imm:$start))>;
+
+def : AlignedVEXTq<v8i8, v16i8, DSubReg_i8_reg>;
+
+def : AlignedVEXTq<v4i16, v8i16, DSubReg_i16_reg>;
+
+def : AlignedVEXTq<v2i32, v4i32, DSubReg_i32_reg>;
+
+def : AlignedVEXTq<v1i64, v2i64, DSubReg_f64_reg>;
+
+def : AlignedVEXTq<v2f32, v4f32, DSubReg_i32_reg>;
+
+
 //   VEXT     : Vector Extract
 
 class VEXTd<string OpcodeStr, string Dt, ValueType Ty>
diff --git a/test/CodeGen/ARM/spill-q.ll b/test/CodeGen/ARM/spill-q.ll
index dc83e25905..bf4e55cb06 100644
--- a/test/CodeGen/ARM/spill-q.ll
+++ b/test/CodeGen/ARM/spill-q.ll
@@ -15,7 +15,10 @@ define void @aaa(%quuz* %this, i8* %block) {
 ; CHECK: vst1.64 {{.*}}sp, :128
 ; CHECK: vld1.64 {{.*}}sp, :128
 entry:
-  %0 = call <4 x float> @llvm.arm.neon.vld1.v4f32(i8* undef, i32 1) nounwind ; <<4 x float>> [#uses=1]
+  %aligned_vec = alloca <4 x float>, align 16
+  %"alloca point" = bitcast i32 0 to i32
+  %vecptr = bitcast <4 x float>* %aligned_vec to i8*
+  %0 = call <4 x float> @llvm.arm.neon.vld1.v4f32(i8* %vecptr, i32 1) nounwind ; <<4 x float>> [#uses=1]
   store float 6.300000e+01, float* undef, align 4
   %1 = call <4 x float> @llvm.arm.neon.vld1.v4f32(i8* undef, i32 1) nounwind ; <<4 x float>> [#uses=1]
   store float 0.000000e+00, float* undef, align 4
diff --git a/test/CodeGen/Thumb2/thumb2-spill-q.ll b/test/CodeGen/Thumb2/thumb2-spill-q.ll
index 0d73fba93e..d9a0617f5a 100644
--- a/test/CodeGen/Thumb2/thumb2-spill-q.ll
+++ b/test/CodeGen/Thumb2/thumb2-spill-q.ll
@@ -15,7 +15,10 @@ define void @aaa(%quuz* %this, i8* %block) {
 ; CHECK: vst1.64 {{.*}}[{{.*}}, :128]
 ; CHECK: vld1.64 {{.*}}[{{.*}}, :128]
 entry:
-  %0 = call <4 x float> @llvm.arm.neon.vld1.v4f32(i8* undef, i32 1) nounwind ; <<4 x float>> [#uses=1]
+  %aligned_vec = alloca <4 x float>, align 16
+  %"alloca point" = bitcast i32 0 to i32
+  %vecptr = bitcast <4 x float>* %aligned_vec to i8*
+  %0 = call <4 x float> @llvm.arm.neon.vld1.v4f32(i8* %vecptr, i32 1) nounwind 
   store float 6.300000e+01, float* undef, align 4
   %1 = call <4 x float> @llvm.arm.neon.vld1.v4f32(i8* undef, i32 1) nounwind ; <<4 x float>> [#uses=1]
   store float 0.000000e+00, float* undef, align 4