1; RUN: opt -O3 -S < %s | FileCheck %s 2target datalayout = "e-m:e-i64:64-i128:128-n32:64-S128" 3target triple = "aarch64" 4 5@v = internal unnamed_addr global i32 0, align 4 6@p = common global i32* null, align 8 7 8 9; This test checks that a number of loads and stores are eliminated, 10; that can only be eliminated based on GlobalsAA information. As such, 11; it tests that GlobalsAA information is retained until the passes 12; that perform this optimization, and it protects against accidentally 13; dropping the GlobalsAA information earlier in the pipeline, which 14; has happened a few times. 15 16; GlobalsAA invalidation might happen later in the FunctionPassManager 17; pipeline than the optimization eliminating unnecessary loads/stores. 18; Since GlobalsAA is a module-level analysis, any FunctionPass 19; invalidating the GlobalsAA information will affect FunctionPass 20; pipelines that execute later. For example, assume a FunctionPass1 | 21; FunctionPass2 pipeline and 2 functions to be processed: f1 and f2. 22; Assume furthermore that FunctionPass1 uses GlobalsAA info to do an 23; optimization, and FunctionPass2 invalidates GlobalsAA. Assume the 24; function passes run in the following order: FunctionPass1(f1), 25; FunctionPass2(f1), FunctionPass1(f2), FunctionPass2(f2). Then 26; FunctionPass1 will not be able to optimize f2, since GlobalsAA will 27; have been invalidated in FuntionPass2(f1). 28 29; To try and also test this scenario, there is an empty function 30; before and after the function we're checking so that one of them 31; will be processed by the whole set of FunctionPasses before @f. That 32; will ensure that if the invalidation happens, it happens before the 33; actual optimizations on @f start. 34define void @bar() { 35entry: 36 ret void 37} 38 39; Function Attrs: norecurse nounwind 40define void @f(i32 %n) { 41entry: 42 %0 = load i32, i32* @v, align 4 43 %inc = add nsw i32 %0, 1 44 store i32 %inc, i32* @v, align 4 45 %1 = load i32*, i32** @p, align 8 46 store i32 %n, i32* %1, align 4 47 %2 = load i32, i32* @v, align 4 48 %inc1 = add nsw i32 %2, 1 49 store i32 %inc1, i32* @v, align 4 50 ret void 51} 52 53; check variable v is loaded/stored only once after optimization, 54; which should be prove that globalsAA survives until the optimization 55; that can use it to optimize away the duplicate load/stores on 56; variable v. 57; CHECK: load i32, i32* @v, align 4 58; CHECK: store i32 {{.*}}, i32* @v, align 4 59; CHECK-NOT: load i32, i32* @v, align 4 60; CHECK-NOT: store i32 {{.*}}, i32* @v, align 4 61 62; Same as @bar above, in case the functions are processed in reverse order. 63define void @bar2() { 64entry: 65 ret void 66} 67