leonardchan added a comment.
I did some more digging and found the following differences between PMs for
each test, and they seem to all differ and can be fixed for different reasons.
**CodeGen/aggregate-assign-call.c**: The new PM on -O1 codegen produces the
do/while loop differently but still emits the lifetime start/end intrinsics
around temporary variables, which is what the test checks for. Here we can just
check for the instructions while ignoring the branches generated.
**CodeGen/arm_acle.c**: A bunch of instructions seem to have been combined into
a call to `llvm.fshl.i32`, so we just check for those under the new PM.
**CodeGen/available-externally-suppress.c**: `available_externally` was not
emitted during `-O2 -flto` runs when it should still be retained for link time
inlining purposes. This can be fixed by checking that we aren't LTOPrelinking
when adding the `EliminateAvailableExternallyPass`.
**CodeGen/pgo-sample.c [No new fix]**: The test checks that `PruneEH` runs, but
there doesn’t seem to be a corresponding new PM pass for it. Should there be?
If there is one then we can just check for that in the debug PM dump.
**CodeGen/x86_64-instrument-functions.c [No new fix]**: This one's a bit
complicated. The initial problem seems to be that `EntryExitInstrumenterPass`
was not added into the pipeline to emit `__cyg_profile_func_enter/exit()`
calls. Adding that to the pipeline seems to instrument correctly now and add
these calls, but we run into a problem with inlining. `root()` expects 2 calls
to `__cyg_profile_func_enter` and 2 calls to `__cyg_profile_func_exit` in its
body,
; Function Attrs: nounwind
define i32 @root(i32 returned %x) #0 {
entry:
%0 = tail call i8* @llvm.returnaddress(i32 0)
tail call void @__cyg_profile_func_enter(i8* bitcast (i32 (i32)* @root to
i8*), i8* %0) #2
tail call void @__cyg_profile_func_enter(i8* bitcast (i32 (i32)* @leaf to
i8*), i8* %0) #2
tail call void @__cyg_profile_func_exit(i8* bitcast (i32 (i32)* @leaf to
i8*), i8* %0) #2
tail call void @__cyg_profile_func_exit(i8* bitcast (i32 (i32)* @root to
i8*), i8* %0) #2
ret i32 %x
}
but we get only 1 call
; Function Attrs: norecurse nounwind readnone
define i32 @root(i32 returned %x) local_unnamed_addr #0 {
entry:
%0 = call i8* @llvm.returnaddress(i32 0)
call void @__cyg_profile_func_enter(i8* bitcast (i32 (i32)* @root to i8*),
i8* %0)
%1 = call i8* @llvm.returnaddress(i32 0)
call void @__cyg_profile_func_exit(i8* bitcast (i32 (i32)* @root to i8*),
i8* %1)
ret i32 %x
}
I suspect this is due to the `leaf()` being inlined into `root()` even though
inlining should happen after it. The legacy `EntryExitInstrumenter` pass seems
to be added to the legacy FunctionPassManager first before all others passes.
Under the legacy PM, when this pass runs, `root()` should look like:
; Function Attrs: nounwind
define i32 @root(i32 %x) #1 {
entry:
%x.addr = alloca i32, align 4
store i32 %x, i32* %x.addr, align 4, !tbaa !2
%0 = load i32, i32* %x.addr, align 4, !tbaa !2
%call = call i32 @leaf(i32 %0) ; this call is not yet inlined
ret i32 %call
}
but `root()` looks like this in the new PM pass:
; Function Attrs: norecurse nounwind readnone
define i32 @root(i32 returned %x) local_unnamed_addr #1 {
entry:
ret i32 %x
}
**CodeGenCXX/auto-var-init.cpp**: Auto var initialization is performed
differently under new PM than legacy. With initialization for structs with
default values, the legacy PM will store the stream of 0xAAs, then initialize
the members with default values in a constructor, whereas the new PM will just
store the correct value for the whole struct right away without initialization.
In one case, it seems that ctor function was also inlined. Fixed by check
accounting for these checks separately.
**CodeGenCXX/conditional-temporaries.cpp**: The new pm seems to be unable to
statically determine the return value of some functions. For now I just add
separate checks for the new PM IR.
**CodeGenCXX/member-function-pointer-calls.cpp**: Same as
`CodeGenCXX/conditional-temporaries.cpp`. In this case, the new PM codegen also
contains calls to lifetime start/end intrinsics. Perhaps this time it could be
due to the intrinsics not being optimized out?
**CodeGenObjC/os_log.m**: Legacy test expects argument of `ptrtoint` and some
functions to be a specific type and argument, though the new PM codegen uses a
different type and argument which are also valid since
`@llvm.objc.retainAutoreleasedReturnValue(val)` always returns `val`.
**CodeGenObjCXX/os_log.mm**: A function seems to have been inlined under the
new PM. Here we just prevent inlining for the new PM run since the test expects
this specific function call.
**Misc/pr32207.c [No new fix]**: The banner is something that appears only in
the legacy PM. I think the test only checks that the banner is printed and not
so much that the particular pass is run.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D63156/new/
https://reviews.llvm.org/D63156
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