Commit 227bd4cb authored by Tom Stellard's avatar Tom Stellard
Browse files

Merging r283599: 

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r283599 | davide | 2016-10-07 13:57:42 -0700 (Fri, 07 Oct 2016) | 4 lines

[InstCombine] Don't unpack arrays that are too large

Differential Revision:  https://reviews.llvm.org/D25376

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llvm-svn: 288069
parent afb3aea9

llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp

+7 −0
Original line number Diff line number Diff line
@@ -579,6 +579,13 @@ static Instruction *unpackLoadToAggregate(InstCombiner &IC, LoadInst &LI) { 
        UndefValue::get(T), NewLoad, 0, Name));

    }



    // 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 nullptr;



    const DataLayout &DL = IC.getDataLayout();

    auto EltSize = DL.getTypeAllocSize(ET);

    auto Align = LI.getAlignment();

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

+8 −0
Original line number Diff line number Diff line
@@ -179,6 +179,14 @@ define [2 x %B] @loadArrayOfB([2 x %B]* %ab.ptr) { 
  ret [2 x %B] %1

}



define [2000 x %B] @loadLargeArrayOfB([2000 x %B]* %ab.ptr) {

; CHECK-LABEL: loadLargeArrayOfB

; CHECK-NEXT: load [2000 x %B], [2000 x %B]* %ab.ptr, align 8

; CHECK-NEXT: ret [2000 x %B]

  %1 = load [2000 x %B], [2000 x %B]* %ab.ptr, align 8

  ret [2000 x %B] %1

}



%struct.S = type <{ i8, %struct.T }>

%struct.T = type { i32, i32 }