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| author | Benjamin Kramer <benny.kra@googlemail.com> | 2012-10-27 14:25:51 +0000 |
|---|---|---|
| committer | Benjamin Kramer <benny.kra@googlemail.com> | 2012-10-27 14:25:51 +0000 |
| commit | d11c5d08a5f4f030d6e357378d0d46d93efd9a59 (patch) | |
| tree | 95e77226ccabfa2fd6c5b171c64f038ccdef512d /test | |
| parent | 96c8735e28f2f89be37cdd907f680c6c1bf16052 (diff) | |
| download | llvm-d11c5d08a5f4f030d6e357378d0d46d93efd9a59.tar.gz llvm-d11c5d08a5f4f030d6e357378d0d46d93efd9a59.tar.bz2 llvm-d11c5d08a5f4f030d6e357378d0d46d93efd9a59.tar.xz | |
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
Diffstat (limited to 'test')
| -rw-r--r-- | test/Transforms/LoopIdiom/basic.ll | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/test/Transforms/LoopIdiom/basic.ll b/test/Transforms/LoopIdiom/basic.ll index 46ab7e5542..5afc405fa6 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), +} |