Commit c47a943d authored by Tanya Lattner's avatar Tanya Lattner
Browse files

Merge 81810 from mainline. 

When extending a memset range past the front, set the alignment of the
memset region to the alignment of the new start address.

llvm-svn: 81976
parent 318048b2

llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp

+1 −0
Original line number Diff line number Diff line
@@ -271,6 +271,7 @@ void MemsetRanges::addStore(int64_t Start, StoreInst *SI) { 
  if (Start < I->Start) {

    I->Start = Start;

    I->StartPtr = SI->getPointerOperand();

    I->Alignment = SI->getAlignment();

  }

    

  // Now we know that Start <= I->End and Start >= I->Start (so the startpoint

llvm/test/Transforms/MemCpyOpt/align.ll

0 → 100644
+18 −0
Original line number Diff line number Diff line 
; RUN: opt < %s -S -memcpyopt | FileCheck %s



; The resulting memset is only 4-byte aligned, despite containing

; a 16-byte alignmed store in the middle.



; CHECK: call void @llvm.memset.i64(i8* %a01, i8 0, i64 16, i32 4)



define void @foo(i32* %p) {

  %a0 = getelementptr i32* %p, i64 0

  store i32 0, i32* %a0, align 4

  %a1 = getelementptr i32* %p, i64 1

  store i32 0, i32* %a1, align 16

  %a2 = getelementptr i32* %p, i64 2

  store i32 0, i32* %a2, align 4

  %a3 = getelementptr i32* %p, i64 3

  store i32 0, i32* %a3, align 4

  ret void

}