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This provides an implementation of CFL alias analysis (including some supporting data structures). Currently, we don't have any extremely fancy features, sans some interprocedural analysis (i.e. no field sensitivity, etc.), and we do best sitting behind BasicAA + TBAA. In such a configuration, we take ~0.6-0.8% of total compile time, and give ~7-8% NoAlias responses to queries TBAA and BasicAA couldn't answer when bootstrapping LLVM. In testing this on other projects, we've seen up to 10.5% of queries dropped by BasicAA+TBAA answered with NoAlias by this algorithm. Patch by George Burgess IV (with minor modifications by me -- mostly adapting some BasicAA tests), thanks! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216970 91177308-0d34-0410-b5e6-96231b3b80d8
37 lines
841 B
LLVM
37 lines
841 B
LLVM
; RUN: opt < %s -cfl-aa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
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; Derived from (a subset of) BasicAA/phi-and-select.ll
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; CHECK: Function: qux
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; CHECK: NoAlias: double* %a, double* %b
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; CHECK: ===== Alias Analysis Evaluator Report =====
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; Two PHIs with disjoint sets of inputs.
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define void @qux(i1 %m, double* noalias %x, double* noalias %y,
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i1 %n, double* noalias %v, double* noalias %w) {
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entry:
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br i1 %m, label %true, label %false
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true:
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br label %exit
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false:
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br label %exit
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exit:
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%a = phi double* [ %x, %true ], [ %y, %false ]
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br i1 %n, label %ntrue, label %nfalse
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ntrue:
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br label %nexit
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nfalse:
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br label %nexit
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nexit:
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%b = phi double* [ %v, %ntrue ], [ %w, %nfalse ]
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store volatile double 0.0, double* %a
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store volatile double 1.0, double* %b
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ret void
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}
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