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llvm-mirror/test/Analysis/BasicAA/2009-10-13-GEP-BaseNoAlias.ll
Evan Cheng 907fd9c3fb Another BasicAA fix. If a value does not alias a GEP's base pointer, then it
cannot alias the GEP. GEP pointer alias rule states this clearly:
A pointer value formed from a getelementptr instruction is associated with the
addresses associated with the first operand of the getelementptr.

llvm-svn: 84079
2009-10-14 06:41:49 +00:00

31 lines
624 B
LLVM

; RUN: opt < %s -aa-eval -print-all-alias-modref-info -disable-output |& grep {NoAlias:.*%P,.*@Z}
; If GEP base doesn't alias Z, then GEP doesn't alias Z.
; rdar://7282591
@Y = common global i32 0
@Z = common global i32 0
define void @foo(i32 %cond) nounwind ssp {
entry:
%a = alloca i32
%tmp = icmp ne i32 %cond, 0
br i1 %tmp, label %bb, label %bb1
bb:
%b = getelementptr i32* %a, i32 0
br label %bb2
bb1:
br label %bb2
bb2:
%P = phi i32* [ %b, %bb ], [ @Y, %bb1 ]
%tmp1 = load i32* @Z, align 4
store i32 123, i32* %P, align 4
%tmp2 = load i32* @Z, align 4
br label %return
return:
ret void
}