forked from OSchip/llvm-project
67 lines
2.5 KiB
LLVM
67 lines
2.5 KiB
LLVM
; RUN: opt -O3 -S < %s | FileCheck %s
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target datalayout = "e-m:e-i64:64-i128:128-n32:64-S128"
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target triple = "aarch64"
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@v = internal unnamed_addr global i32 0, align 4
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@p = common global i32* null, align 8
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; This test checks that a number of loads and stores are eliminated,
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; that can only be eliminated based on GlobalsAA information. As such,
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; it tests that GlobalsAA information is retained until the passes
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; that perform this optimization, and it protects against accidentally
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; dropping the GlobalsAA information earlier in the pipeline, which
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; has happened a few times.
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; GlobalsAA invalidation might happen later in the FunctionPassManager
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; pipeline than the optimization eliminating unnecessary loads/stores.
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; Since GlobalsAA is a module-level analysis, any FunctionPass
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; invalidating the GlobalsAA information will affect FunctionPass
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; pipelines that execute later. For example, assume a FunctionPass1 |
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; FunctionPass2 pipeline and 2 functions to be processed: f1 and f2.
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; Assume furthermore that FunctionPass1 uses GlobalsAA info to do an
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; optimization, and FunctionPass2 invalidates GlobalsAA. Assume the
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; function passes run in the following order: FunctionPass1(f1),
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; FunctionPass2(f1), FunctionPass1(f2), FunctionPass2(f2). Then
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; FunctionPass1 will not be able to optimize f2, since GlobalsAA will
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; have been invalidated in FuntionPass2(f1).
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; To try and also test this scenario, there is an empty function
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; before and after the function we're checking so that one of them
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; will be processed by the whole set of FunctionPasses before @f. That
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; will ensure that if the invalidation happens, it happens before the
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; actual optimizations on @f start.
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define void @bar() {
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entry:
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ret void
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}
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; Function Attrs: norecurse nounwind
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define void @f(i32 %n) {
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entry:
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%0 = load i32, i32* @v, align 4
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%inc = add nsw i32 %0, 1
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store i32 %inc, i32* @v, align 4
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%1 = load i32*, i32** @p, align 8
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store i32 %n, i32* %1, align 4
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%2 = load i32, i32* @v, align 4
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%inc1 = add nsw i32 %2, 1
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store i32 %inc1, i32* @v, align 4
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ret void
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}
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; check variable v is loaded/stored only once after optimization,
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; which should be prove that globalsAA survives until the optimization
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; that can use it to optimize away the duplicate load/stores on
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; variable v.
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; CHECK: load i32, i32* @v, align 4
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; CHECK: store i32 {{.*}}, i32* @v, align 4
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; CHECK-NOT: load i32, i32* @v, align 4
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; CHECK-NOT: store i32 {{.*}}, i32* @v, align 4
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; Same as @bar above, in case the functions are processed in reverse order.
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define void @bar2() {
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entry:
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ret void
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}
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