Refine tail call conditions for tail and musttail markers
#1094
Conversation
antoniofrighetto
force-pushed
the
feature/refine-tail-calls
branch
2 times, most recently
from
fead176
to
05d48bc
Compare
There was a problem hiding this comment.
why delete this test? it's correct
There was a problem hiding this comment.
Moved it to musttail-memcpy.srctgt.ll and replace tail w/ musttail (since with tail only marker it shouldn't be UB, we're verifying only isMustTailCall now).
| %call2 = alloca i64 | ||
| %call3 = alloca i64 | ||
| store i64 %arg, ptr %call2, align 8 | ||
| musttail call tailcc void @llvm.memcpy.p0.p0.i64(ptr byval(ptr) %call3, ptr byval(ptr) %call2, i64 8, i1 false) |
There was a problem hiding this comment.
this not a good test because it's mixing several conditions at once
There was a problem hiding this comment.
Separated it in multiple functions.
|
I think we miss checking the following:
(Not completely sure if this refers to musttail too though) |
|
From a quick read, this doesn't seem to be what we want at all. We need both tail & musttail, as both have constraints. |
antoniofrighetto
force-pushed
the
feature/refine-tail-calls
branch
2 times, most recently
from
78c3527
to
69bb131
Compare
|
Added a new type |
antoniofrighetto
changed the title
musttailtail and musttail markers
| @@ -0,0 +1,11 @@ | |||
| define tailcc i64 @src(i64 noundef %arg) { | |||
There was a problem hiding this comment.
this test doesn't seem very useful; doesn't check for anything.
There was a problem hiding this comment.
Dropped it.
| store i64 %arg, ptr %call2, align 8 | ||
| tail call void @llvm.memcpy.p0.p0.i64(ptr %call3, ptr %call2, i64 8, i1 false) | ||
| ret i64 poison | ||
| ret i64 undef |
There was a problem hiding this comment.
use poison instead pls. we want to get rid of undef
llvm_util/utils.cpp
Outdated
| @@ -521,4 +525,67 @@ llvm::Function *findFunction(llvm::Module &M, const string &FName) { | |||
| return F && !F->isDeclaration() ? F : nullptr; | |||
| } | |||
|
|
|||
| TailCallInfo parse_tail_call_info(const llvm::CallInst &i) { | |||
There was a problem hiding this comment.
we don't encode semantics like this. The semantics must be in the ir folder.
We support other IRs -> Alive2 IR, hence we do as little as possible in the translation.
There was a problem hiding this comment.
I left parse_tail_call_info in utils.cpp so that it may be used from known_functions too (originally was in llvm2alive). I think we still need it there as we're parsing data from LLVM (like parse_fn_attrs). Do you mean that the semantics in are_tailcall_preconditions_met is to be moved in ir inside check_tailcall?
There was a problem hiding this comment.
Also made it more coherent (parse_tail_call_info -> parse_fn_tailcall).
llvm_util/known_fns.cpp
Outdated
| switch (libfn) { | ||
| case llvm::LibFunc_memset: // void* memset(void *ptr, int val, size_t bytes) | ||
| BB.addInstr(make_unique<Memset>(*args[0], *args[1], *args[2], 1, is_tailcall)); | ||
| BB.addInstr(make_unique<Memset>(*args[0], *args[1], *args[2], 1, | ||
| std::move(tci))); |
There was a problem hiding this comment.
To be changed after the change above.
antoniofrighetto
force-pushed
the
feature/refine-tail-calls
branch
from
5847a38
to
0c8b3cf
Compare
|
Updated, moved semantics in checkTailCall. |
antoniofrighetto
force-pushed
the
feature/refine-tail-calls
branch
from
0c8b3cf
to
34d311f
Compare
musttail has stronger requirements than tail, so ensure this is taken into account.