diff --git a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp index bc8ae660366d..249cb9dcaaf6 100644 --- a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp +++ b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp @@ -555,10 +555,11 @@ processLoopStoreOfLoopLoad(StoreInst *SI, unsigned StoreSize, // can safely emit a memcpy. OwningPtr Dep(DA.depends(SI, LI, true)); if (Dep) { - // If there is a dependence but the direction is positive we can still - // safely turn this into memmove. - if (Dep->getLevels() != 1 || - Dep->getDirection(1) != Dependence::DVEntry::GT) + // If there is a dependence but the direction is positive (or none) we can + // still safely turn this into memmove. + unsigned Direction = Dep->getDirection(Dep->getLevels()); + if (Direction != Dependence::DVEntry::NONE && + Direction != Dependence::DVEntry::GT) return false; isMemcpySafe = false; } diff --git a/llvm/test/Transforms/LoopIdiom/memmove.ll b/llvm/test/Transforms/LoopIdiom/memmove.ll new file mode 100644 index 000000000000..bfa0902a0d2b --- /dev/null +++ b/llvm/test/Transforms/LoopIdiom/memmove.ll @@ -0,0 +1,42 @@ +; RUN: opt -S -basicaa -loop-idiom < %s | FileCheck %s +target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128" +target triple = "x86_64-apple-macosx10.8.0" + +declare i64 @foo() nounwind + +; Nested loops +define void @test1(i8* nocapture %A, i64 %n) nounwind { +entry: + %call8 = tail call i64 @foo() nounwind + %tobool9 = icmp eq i64 %call8, 0 + br i1 %tobool9, label %while.end, label %for.cond.preheader.lr.ph + +for.cond.preheader.lr.ph: ; preds = %entry + %cmp6 = icmp eq i64 %n, 0 + br label %for.cond.preheader + +while.cond.loopexit: ; preds = %for.body, %for.cond.preheader + %call = tail call i64 @foo() nounwind + %tobool = icmp eq i64 %call, 0 + br i1 %tobool, label %while.end, label %for.cond.preheader + +for.cond.preheader: ; preds = %for.cond.preheader.lr.ph, %while.cond.loopexit + br i1 %cmp6, label %while.cond.loopexit, label %for.body + +for.body: ; preds = %for.cond.preheader, %for.body + %i.07 = phi i64 [ %inc, %for.body ], [ 0, %for.cond.preheader ] + %add = add i64 %i.07, 10 + %arrayidx = getelementptr inbounds i8* %A, i64 %add + %0 = load i8* %arrayidx, align 1 + %arrayidx1 = getelementptr inbounds i8* %A, i64 %i.07 + store i8 %0, i8* %arrayidx1, align 1 + %inc = add i64 %i.07, 1 + %exitcond = icmp eq i64 %inc, %n + br i1 %exitcond, label %while.cond.loopexit, label %for.body + +while.end: ; preds = %while.cond.loopexit, %entry + ret void + +; CHECK: @test1 +; CHECK: call void @llvm.memmove.p0i8.p0i8.i64( +}