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llvm-mirror/test/Transforms/PhaseOrdering/globalaa-retained.ll
Arthur Eubanks cdf50f8461 [NewPM][opt] Run the "default" AA pipeline by default
We tend to assume that the AA pipeline is by default the default AA
pipeline and it's confusing when it's empty instead.

PR48779

Initially reverted due to BasicAA running analyses in an unspecified
order (multiple function calls as parameters), fixed by fetching
analyses before the call to construct BasicAA.

Reviewed By: asbirlea

Differential Revision: https://reviews.llvm.org/D95117
2021-01-21 21:08:54 -08:00

68 lines
2.6 KiB
LLVM

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