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| author | Dan Gohman <gohman@apple.com> | 2011-06-04 00:31:50 +0000 |
|---|---|---|
| committer | Dan Gohman <gohman@apple.com> | 2011-06-04 00:31:50 +0000 |
| commit | 1fc18d71deb0e23a9101c87bb7b1455098ce1c09 (patch) | |
| tree | c3608fae328c29f981be6de0d4c44452f0d025e6 /test/Analysis | |
| parent | 865f09334f67edb2000fb38c6c3c28283b88b3bf (diff) | |
| download | llvm-1fc18d71deb0e23a9101c87bb7b1455098ce1c09.tar.gz llvm-1fc18d71deb0e23a9101c87bb7b1455098ce1c09.tar.bz2 llvm-1fc18d71deb0e23a9101c87bb7b1455098ce1c09.tar.xz | |
Fix BasicAA's recursion detection so that it doesn't pessimize
queries in the case of a DAG, where a query reaches a node
visited earlier, but it's not on a cycle. This avoids
MayAlias results in cases where BasicAA is expected to
return MustAlias or PartialAlias in order to protect TBAA.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132609 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/Analysis')
| -rw-r--r-- | test/Analysis/BasicAA/dag.ll | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/test/Analysis/BasicAA/dag.ll b/test/Analysis/BasicAA/dag.ll new file mode 100644 index 0000000000..501f4c399b --- /dev/null +++ b/test/Analysis/BasicAA/dag.ll @@ -0,0 +1,41 @@ +; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info |& 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" + +; BasicAA's guard against use-def cycles shouldn't prevent it from +; analyzing use-def dags. + +; CHECK: MustAlias: i8* %base, i8* %phi +; CHECK: MustAlias: i8* %phi, i8* %wwa +; CHECK: MustAlias: i8* %phi, i8* %wwb +; CHECK: MustAlias: i16* %bigbase, i8* %phi +define i8 @foo(i8* %base, i1 %x, i1 %w) { +entry: + br i1 %w, label %wa, label %wb +wa: + %wwa = bitcast i8* %base to i8* + br label %wc +wb: + %wwb = bitcast i8* %base to i8* + br label %wc +wc: + %first = phi i8* [ %wwa, %wa ], [ %wwb, %wb ] + %fc = bitcast i8* %first to i8* + br i1 %x, label %xa, label %xb +xa: + %xxa = bitcast i8* %fc to i8* + br label %xc +xb: + %xxb = bitcast i8* %fc to i8* + br label %xc +xc: + %phi = phi i8* [ %xxa, %xa ], [ %xxb, %xb ] + + store i8 0, i8* %phi + + %bigbase = bitcast i8* %base to i16* + store i16 -1, i16* %bigbase + + %loaded = load i8* %phi + ret i8 %loaded +} |