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c01563abdd
In BasicAA GEP operand values get adjusted ("wrap-around") based on the
pointersize. Otherwise, in non-64b modes, AA could report false negatives.
However, a wrap-around is valid only for a fully evaluated expression.
It had been introduced to fix an alias problem in
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160118/326163.html.
This commit restricts the wrap-around to constant gep operands only where the
value is known at compile-time.
llvm-svn: 284908
44 lines
1.6 KiB
LLVM
44 lines
1.6 KiB
LLVM
; RUN: opt -S -basicaa -gvn < %s | FileCheck %s
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target datalayout = "e-m:o-p:32:32-f64:32:64-f80:128-n8:16:32-S128"
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target triple = "i386-apple-macosx10.6.0"
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; The load and store address in the loop body could alias so the load
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; can't be hoisted above the store and out of the loop.
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declare void @llvm.memset.p0i8.i32(i8* nocapture writeonly, i8, i32, i32, i1)
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define i32 @foo(i32 %x, i32 %z, i32 %n) {
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entry:
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%pool = alloca [59 x i32], align 4
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%tmp = bitcast [59 x i32]* %pool to i8*
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call void @llvm.memset.p0i8.i32(i8* nonnull %tmp, i8 0, i32 236, i32 4, i1 false)
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%cmp3 = icmp eq i32 %n, 0
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br i1 %cmp3, label %for.end, label %for.body.lr.ph
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for.body.lr.ph: ; preds = %entry
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%add = add i32 %z, %x
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%and = and i32 %add, 2147483647
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%sub = add nsw i32 %and, -2137521902
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%arrayidx = getelementptr inbounds [59 x i32], [59 x i32]* %pool, i32 0, i32 %sub
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%arrayidx1 = getelementptr inbounds [59 x i32], [59 x i32]* %pool, i32 0, i32 42
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br label %for.body
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for.body: ; preds = %for.body.lr.ph, %for.body
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%i.04 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.body ]
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store i32 %i.04, i32* %arrayidx, align 4
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%tmp1 = load i32, i32* %arrayidx1, align 4
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%inc = add nuw i32 %i.04, 1
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%exitcond = icmp ne i32 %inc, %n
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br i1 %exitcond, label %for.body, label %for.end.loopexit
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for.end.loopexit: ; preds = %for.body
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%lcssa = phi i32 [ %tmp1, %for.body ]
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br label %for.end
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for.end: ; preds = %for.end.loopexit, %entry
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%s = phi i32 [ 0, %entry ], [ %lcssa, %for.end.loopexit ]
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; CHECK: ret i32 %s
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ret i32 %s
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}
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