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llvm-mirror/test/Transforms/SampleProfile/cold-indirect-call.ll
Wei Mi 93d80a543f [SampleFDO] Add use-sample-profile function attribute.
When sampleFDO is enabled, people may expect they can use
-fno-profile-sample-use to opt-out using sample profile for a certain file.
That could be either for debugging purpose or for performance tuning purpose.
However, when thinlto is enabled, if a function in file A compiled with
-fno-profile-sample-use is imported to another file B compiled with
-fprofile-sample-use, the inlined copy of the function in file B may still
get its profile annotated.

The inconsistency may even introduce profile unused warning because if the
target is not compiled with explicit debug information flag, the function
in file A won't have its debug information enabled (debug information will
be enabled implicitly only when -fprofile-sample-use is used). After it is
imported into file B which is compiled with -fprofile-sample-use, profile
annotation for the outline copy of the function will fail because the
function has no debug information, and that will trigger  profile unused
warning.

We add a new attribute use-sample-profile to control whether a function
will use its sample profile no matter for its outline or inline copies.
That will make the behavior of -fno-profile-sample-use consistent.

Differential Revision: https://reviews.llvm.org/D79959
2020-06-02 17:23:17 -07:00

33 lines
1.1 KiB
LLVM

; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/cold-indirect-call.prof -S | FileCheck %s
; RUN: opt < %s -passes=sample-profile -sample-profile-file=%S/Inputs/cold-indirect-call.prof -S | FileCheck %s
define i32 @foo(i32 ()* %func) #0 !dbg !3 {
; CHECK: icmp {{.*}} @bar
; CHECK-NOT: icmp {{.*}} @baz
%call = call i32 %func(), !dbg !4
ret i32 %call
}
define i32 @bar() #0 !dbg !5 {
ret i32 41, !dbg !6
}
define i32 @baz() #0 !dbg !7 {
ret i32 42, !dbg !8
}
attributes #0 = {"use-sample-profile"}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!2}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1)
!1 = !DIFile(filename: "foo.cc", directory: "/")
!2 = !{i32 2, !"Debug Info Version", i32 3}
!3 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 4, unit: !0)
!4 = !DILocation(line: 5, scope: !3)
!5 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 8, unit: !0)
!6 = !DILocation(line: 9, scope: !5)
!7 = distinct !DISubprogram(name: "baz", scope: !1, file: !1, line: 12, unit: !0)
!8 = !DILocation(line: 13, scope: !7)