[MemCpyOpt] Do not exchange llvm.lifetime.start and llvm.memcpy
Reviewers: iteratee Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D21087 llvm-svn: 272192
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@ -788,6 +788,11 @@ bool MemCpyOpt::performCallSlotOptzn(Instruction *cpy,
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// src only holds uninitialized values at the moment of the call, meaning that
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// the memcpy can be discarded rather than moved.
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// Lifetime marks shouldn't be operated on.
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if (Function *F = C->getCalledFunction())
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if (F->isIntrinsic() && F->getIntrinsicID() == Intrinsic::lifetime_start)
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return false;
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// Deliberately get the source and destination with bitcasts stripped away,
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// because we'll need to do type comparisons based on the underlying type.
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CallSite CS(C);
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@ -0,0 +1,25 @@
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; RUN: opt < %s -O1 -S | FileCheck %s
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; performCallSlotOptzn in MemCpy should not exchange the calls to
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; @llvm.lifetime.start and @llvm.memcpy.
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declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i32, i1) #1
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declare void @llvm.lifetime.start(i64, i8* nocapture) #1
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declare void @llvm.lifetime.end(i64, i8* nocapture) #1
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define void @_ZN4CordC2EOS_(i8* nocapture dereferenceable(16) %arg1) {
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bb:
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; CHECK-LABEL: @_ZN4CordC2EOS_
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; CHECK-NOT: call void @llvm.lifetime.start
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; CHECK: ret void
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%tmp = alloca [8 x i8], align 8
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%tmp5 = bitcast [8 x i8]* %tmp to i8*
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call void @llvm.lifetime.start(i64 16, i8* %tmp5)
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%tmp10 = getelementptr inbounds i8, i8* %tmp5, i64 7
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store i8 0, i8* %tmp10, align 1
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call void @llvm.memcpy.p0i8.p0i8.i64(i8* %arg1, i8* %tmp5, i64 16, i32 8, i1 false)
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call void @llvm.lifetime.end(i64 16, i8* %tmp5)
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ret void
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}
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attributes #1 = { argmemonly nounwind }
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