From d11c5d08a5f4f030d6e357378d0d46d93efd9a59 Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Sat, 27 Oct 2012 14:25:51 +0000 Subject: LoopIdiom: Recognize memmove loops. This turns loops like for (unsigned i = 0; i != n; ++i) p[i] = p[i+1]; into memmove, which has a highly optimized implementation in most libcs. This was really easy with the new DependenceAnalysis :) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166875 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/Transforms/LoopIdiom/basic.ll | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'test/Transforms/LoopIdiom/basic.ll') diff --git a/test/Transforms/LoopIdiom/basic.ll b/test/Transforms/LoopIdiom/basic.ll index 46ab7e5..5afc405 100644 --- a/test/Transforms/LoopIdiom/basic.ll +++ b/test/Transforms/LoopIdiom/basic.ll @@ -383,4 +383,26 @@ for.end: ; preds = %for.inc } +@p = common global [1024 x i8] zeroinitializer, align 16 +define void @test15(i32 %n) nounwind { +entry: + %cmp6 = icmp eq i32 %n, 0 + br i1 %cmp6, label %for.end, label %for.body + +for.body: ; preds = %entry, %for.body + %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ] + %indvars.iv.next = add i64 %indvars.iv, 1 + %arrayidx = getelementptr inbounds [1024 x i8]* @p, i64 0, i64 %indvars.iv.next + %0 = load i8* %arrayidx, align 1 + %arrayidx2 = getelementptr inbounds [1024 x i8]* @p, i64 0, i64 %indvars.iv + store i8 %0, i8* %arrayidx2, align 1 + %lftr.wideiv = trunc i64 %indvars.iv.next to i32 + %exitcond = icmp eq i32 %lftr.wideiv, %n + br i1 %exitcond, label %for.end, label %for.body + +for.end: ; preds = %for.body, %entry + ret void +; CHECK: @test15 +; CHECK: call void @llvm.memmove.p0i8.p0i8.i64(i8* getelementptr inbounds ([1024 x i8]* @p, i32 0, i32 0), i8* getelementptr inbounds ([1024 x i8]* @p, i64 0, i64 1), +} -- cgit v1.1