Fixed a bug in splitting Scatter operation in the Type Legalizer.

After the split of the Scatter operation, the order of the new instructions is well defined - Lo goes before Hi. Otherwise the semantic of Scatter (from LSB to MSB) is broken.
I'm chaining 2 nodes to prevent reordering.

Differential Revision https://reviews.llvm.org/D37670

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312894 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
index b65f47eff1c151e2713f0b4f1c46d57c6f2c2c82..b2839414173dce2396cd8850269329da7953bd99 100644 (file)
--- a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -1970,13 +1970,12 @@ SDValue DAGTypeLegalizer::SplitVecOp_MSCATTER(MaskedScatterSDNode *N,
                          MachineMemOperand::MOStore,  HiMemVT.getStoreSize(),
                          Alignment, N->getAAInfo(), N->getRanges());
 
-  SDValue OpsHi[] = {Ch, DataHi, MaskHi, Ptr, IndexHi};
-  Hi = DAG.getMaskedScatter(DAG.getVTList(MVT::Other), DataHi.getValueType(),
-                            DL, OpsHi, MMO);
-
-  // Build a factor node to remember that this store is independent of the
-  // other one.
-  return DAG.getNode(ISD::TokenFactor, DL, MVT::Other, Lo, Hi);
+  // The order of the Scatter operation after split is well defined. The "Hi"
+  // part comes after the "Lo". So these two operations should be chained one
+  // after another.
+  SDValue OpsHi[] = {Lo, DataHi, MaskHi, Ptr, IndexHi};
+  return DAG.getMaskedScatter(DAG.getVTList(MVT::Other), DataHi.getValueType(),
+                              DL, OpsHi, MMO);
 }
 
 SDValue DAGTypeLegalizer::SplitVecOp_STORE(StoreSDNode *N, unsigned OpNo) {

diff --git a/test/CodeGen/X86/scatter-schedule.ll b/test/CodeGen/X86/scatter-schedule.ll
index 50c63b388ec8b8db2624e11cb5cb460e66045d27..3b26a7c23a8f1172942fafc0686ce78bc2e5e51f 100644 (file)
--- a/test/CodeGen/X86/scatter-schedule.ll
+++ b/test/CodeGen/X86/scatter-schedule.ll
@@ -5,16 +5,15 @@ target triple = "x86_64-unknown-linux-gnu"
 
 ; This test checks the order of scatter operations after split.
 ; The right order is "from LSB to MSB", otherwise the semantic is broken.
-; The submitted version of the test demonstrates the bug.
 
 define void @test(i64 %x272, <16 x i32*> %x335, <16 x i32> %x270) {
 ; CHECK-LABEL: test:
 ; CHECK:       # BB#0:
-; CHECK-NEXT:    vextracti64x4 $1, %zmm2, %ymm3
 ; CHECK-NEXT:    kxnorw %k0, %k0, %k1
 ; CHECK-NEXT:    kxnorw %k0, %k0, %k2
-; CHECK-NEXT:    vpscatterqd %ymm3, (,%zmm1) {%k2}
-; CHECK-NEXT:    vpscatterqd %ymm2, (,%zmm0) {%k1}
+; CHECK-NEXT:    vpscatterqd %ymm2, (,%zmm0) {%k2}
+; CHECK-NEXT:    vextracti64x4 $1, %zmm2, %ymm0
+; CHECK-NEXT:    vpscatterqd %ymm0, (,%zmm1) {%k1}
 ; CHECK-NEXT:    vzeroupper
 ; CHECK-NEXT:    retq
   call void @llvm.masked.scatter.v16i32.v16p0i32(<16 x i32> %x270, <16 x i32*> %x335, i32 4, <16 x i1> <i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true>)