Commit 5e21eeb9 authored by Tom Stellard's avatar Tom Stellard
Browse files

Merging r283612: 

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r283612 | davide | 2016-10-07 14:53:09 -0700 (Fri, 07 Oct 2016) | 5 lines

[InstCombine] Don't unpack arrays that are too large (part 2).

This is similar to r283599, but for store instructions.
Thanks to David for pointing out!

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llvm-svn: 288070
parent 227bd4cb

llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp

+7 −0
Original line number Diff line number Diff line
@@ -1088,6 +1088,13 @@ static bool unpackStoreToAggregate(InstCombiner &IC, StoreInst &SI) { 
      return true;

    }



    // Bail out if the array is too large. Ideally we would like to optimize

    // arrays of arbitrary size but this has a terrible impact on compile time.

    // The threshold here is chosen arbitrarily, maybe needs a little bit of

    // tuning.

    if (NumElements > 1024)

      return false;



    const DataLayout &DL = IC.getDataLayout();

    auto EltSize = DL.getTypeAllocSize(AT->getElementType());

    auto Align = SI.getAlignment();

llvm/test/Transforms/InstCombine/unpack-fca.ll

+9 −0
Original line number Diff line number Diff line
@@ -49,6 +49,15 @@ define void @storeArrayOfA([1 x %A]* %aa.ptr) { 
  ret void

}



define void @storeLargeArrayOfA([2000 x %A]* %aa.ptr) {

; CHECK-LABEL: storeLargeArrayOfA

; CHECK-NEXT: store [2000 x %A]

; CHECK-NEXT: ret void

  %i1 = insertvalue [2000 x %A] undef, %A { %A__vtbl* @A__vtblZ }, 1

  store [2000 x %A] %i1, [2000 x %A]* %aa.ptr, align 8

  ret void

}



define void @storeStructOfArrayOfA({ [1 x %A] }* %saa.ptr) {

; CHECK-LABEL: storeStructOfArrayOfA

; CHECK-NEXT: [[GEP:%[a-z0-9\.]+]] = getelementptr inbounds { [1 x %A] }, { [1 x %A] }* %saa.ptr, i64 0, i32 0, i64 0, i32 0