vendor/llvm/llvm-trunk-r238337

1 files changed, 47 insertions, 0 deletions

diff --git a/test/Analysis/LoopAccessAnalysis/underlying-objects-1.ll b/test/Analysis/LoopAccessAnalysis/underlying-objects-1.ll
new file mode 100644
index 0000000000000..44820ed372221
--- /dev/null
+++ b/test/Analysis/LoopAccessAnalysis/underlying-objects-1.ll
@@ -0,0 +1,47 @@
+; RUN: opt -basicaa -loop-accesses -analyze < %s | FileCheck %s
+
+; In:
+;
+;   store_ptr = A;
+;   load_ptr = &A[2];
+;   for (i = 0; i < n; i++)
+;    *store_ptr++ = *load_ptr++ *10;  // A[i] = A[i+2] * 10
+;
+; make sure, we look through the PHI to conclude that store_ptr and load_ptr
+; both have A as their underlying object.  The dependence is safe for
+; vectorization requiring no memchecks.
+;
+; Otherwise we would try to prove independence with a memcheck that is going
+; to always fail.
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.10.0"
+
+; CHECK: Memory dependences are safe{{$}}
+
+define void @f(i8* noalias %A, i64 %width) {
+for.body.preheader:
+  %A_ahead = getelementptr inbounds i8, i8* %A, i64 2
+  br label %for.body
+
+for.body:
+  %i = phi i64 [ %i.1, %for.body ], [ 0, %for.body.preheader ]
+  %load_ptr = phi i8* [ %load_ptr.1, %for.body ], [ %A_ahead, %for.body.preheader ]
+  %store_ptr = phi i8* [ %store_ptr.1, %for.body ], [ %A, %for.body.preheader ]
+
+  %loadA = load i8, i8* %load_ptr, align 1
+
+  %mul = mul i8 %loadA, 10
+
+  store i8 %mul, i8* %store_ptr, align 1
+
+  %load_ptr.1 = getelementptr inbounds i8, i8* %load_ptr, i64 1
+  %store_ptr.1 = getelementptr inbounds i8, i8* %store_ptr, i64 1
+  %i.1 = add nuw i64 %i, 1
+
+  %exitcond = icmp eq i64 %i.1, %width
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
+}