[llvm-bugs] [Bug 27816] New: [AArch64] continue merging consecutive stores when the next store has different type in store sequences

[via llvm-bugs]

https://llvm.org/bugs/show_bug.cgi?id=27816

            Bug ID: 27816
           Summary: [AArch64] continue merging consecutive stores when the
                    next store has different type in store sequences
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: All
            Status: NEW
          Severity: normal
          Priority: P
         Component: Backend: AArch64
          Assignee: unassignedbugs at nondot.org
          Reporter: junbuml at codeaurora.org
                CC: llvm-bugs at lists.llvm.org
    Classification: Unclassified

In test case below, the consecutive i8 stores are merged into a i64 store.
However, if there is different type of store at the end of the chain which is
commented below, it will not merge other possible stores.

%struct.A = type { i8, i8, i8, i8, i8, i8, i8, i8, i32 }

define void @merge_const_store(i32 %count, %struct.A* nocapture %p)  {
  %1 = icmp sgt i32 %count, 0
  br i1 %1, label %.lr.ph, label %._crit_edge
.lr.ph:
  %i.02 = phi i32 [ %add, %.lr.ph ], [ 0, %0 ]
  %.01 = phi %struct.A* [ %addr, %.lr.ph ], [ %p, %0 ]
  %a2 = getelementptr inbounds %struct.A, %struct.A* %.01, i64 0, i32 0
  store i8 1, i8* %a2, align 1
  %a3 = getelementptr inbounds %struct.A, %struct.A* %.01, i64 0, i32 1
  store i8 2, i8* %a3, align 1
  %a4 = getelementptr inbounds %struct.A, %struct.A* %.01, i64 0, i32 2
  store i8 3, i8* %a4, align 1
  %a5 = getelementptr inbounds %struct.A, %struct.A* %.01, i64 0, i32 3
  store i8 4, i8* %a5, align 1
  %a6 = getelementptr inbounds %struct.A, %struct.A* %.01, i64 0, i32 4
  store i8 5, i8* %a6, align 1
  %a7 = getelementptr inbounds %struct.A, %struct.A* %.01, i64 0, i32 5
  store i8 6, i8* %a7, align 1
  %a8 = getelementptr inbounds %struct.A, %struct.A* %.01, i64 0, i32 6
  store i8 7, i8* %a8, align 1
  %a9 = getelementptr inbounds %struct.A, %struct.A* %.01, i64 0, i32 7
  store i8 8, i8* %a9, align 1

  ;;;;;;;;;;;;
  ; If we uncomment this i32 store, above 8 stores will not merged.
  ;%addr_last = getelementptr inbounds %struct.A, %struct.A* %.01, i64 0, i32 8
  ;store i32 0, i32* %addr_last, align 4
  ;;;;;;;;;;;;

  %add = add nsw i32 %i.02, 1
  %addr = getelementptr inbounds %struct.A, %struct.A* %.01, i64 1
  %exitcond = icmp eq i32 %add, %count
  br i1 %exitcond, label %._crit_edge, label %.lr.ph
._crit_edge:
  ret void
}

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20160519/562d5672/attachment.html>