From: Nirav Dave <niravd@google.com>
Date: Thu, 3 Aug 2017 15:51:20 +0000 (+0000)
Subject: [DAG]  Allow merging of stores of vector loads
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=b6b032495a4dd2ca4079a48d1ab9bbd889afcf87;p=llvm

[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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@309951 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 35a718e1fbf..937522ea2db 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -12719,12 +12719,6 @@ bool DAGCombiner::MergeConsecutiveStores(StoreSDNode *St) {
   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);
diff --git a/test/CodeGen/X86/MergeConsecutiveStores.ll b/test/CodeGen/X86/MergeConsecutiveStores.ll
index 55ff1498806..40ef993ce04 100644
--- a/test/CodeGen/X86/MergeConsecutiveStores.ll
+++ b/test/CodeGen/X86/MergeConsecutiveStores.ll
@@ -535,10 +535,9 @@ define void @merge_vec_stores_from_loads(<4 x float>* %v, <4 x float>* %ptr) {
   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
 }