[llvm] r309951 - [DAG] Allow merging of stores of vector loads

[Nirav Dave via llvm-commits]

Author: niravd
Date: Thu Aug  3 08:51:20 2017
New Revision: 309951

URL: http://llvm.org/viewvc/llvm-project?rev=309951&view=rev
Log:
[DAG]  Allow merging of stores of vector loads

Remove restriction disallowing merging of stores vector loads into
larger store of larger vector load.

Reviewers: RKSimon, efriedma, spatel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D36158

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
    llvm/trunk/test/CodeGen/X86/MergeConsecutiveStores.ll

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=309951&r1=309950&r2=309951&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Thu Aug  3 08:51:20 2017
@@ -12719,12 +12719,6 @@ bool DAGCombiner::MergeConsecutiveStores
   if (!IsConstantSrc && !IsLoadSrc && !IsExtractVecSrc)
     return false;
 
-  // Don't merge vectors into wider vectors if the source data comes from loads.
-  // TODO: This restriction can be lifted by using logic similar to the
-  // ExtractVecSrc case.
-  if (MemVT.isVector() && IsLoadSrc)
-    return false;
-
   SmallVector<MemOpLink, 8> StoreNodes;
   // Find potential store merge candidates by searching through chain sub-DAG
   getStoreMergeCandidates(St, StoreNodes);

Modified: llvm/trunk/test/CodeGen/X86/MergeConsecutiveStores.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/MergeConsecutiveStores.ll?rev=309951&r1=309950&r2=309951&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/MergeConsecutiveStores.ll (original)
+++ llvm/trunk/test/CodeGen/X86/MergeConsecutiveStores.ll Thu Aug  3 08:51:20 2017
@@ -535,10 +535,9 @@ define void @merge_vec_stores_from_loads
   ret void
 
 ; CHECK-LABEL: merge_vec_stores_from_loads
-; CHECK:      vmovaps
-; CHECK-NEXT: vmovaps
-; CHECK-NEXT: vmovaps
-; CHECK-NEXT: vmovaps
+; CHECK:      vmovups (%rdi), %ymm0
+; CHECK-NEXT: vmovups %ymm0, (%rsi)
+; CHECK-NEXT: vzeroupper
 ; CHECK-NEXT: retq
 }