Much like with function reduction, there may be remaining unhandled uses
of function, in particular in blockaddress. And in constants we can't
RAUW it with undef, because undef is not a function.
Instead, let's try to pretent that in the remaining cases, the new
signature didn't change, by bitcasting it.
A new (previously crashing) test case added.
We can happily turn function definitions into declarations,
thus obscuring their argument from being elided by this pass.
I don't believe there is a good reason to just ignore declarations.
likely even proper llvm intrinsics ones,
at worst the input becomes uninteresting.
The other question here is that all these transforms are all-or-nothing.
In some cases, should we be treating each use separately?
The main blocker here seemed to be that llvm::CloneFunctionInto()
does `&OldFunc->front()`, which inserts a nullptr into a densemap,
which is not happy about it and asserts.
replaceFunctionCalls() is very non-exhaustive, it only handles
CallInst's. Which means, by the time we drop old function,
there may still be uses of it lurking around.
Let's instead whack-a-mole them by all by replacing with undef.
I'm not sure this is the best handling, especially for calls, but IMO
poorly reduced input is much better than crashing reduction tool.
A (previously-crashing!) test added.
Fixes https://bugs.llvm.org/show_bug.cgi?id=46819
Newly-added test previously crashed.
While it is up for debate whether or not instruction reduction
should be indiscriminate in instruction dropping (there you can
just ensure that the test case is still -verify'ies), here
if we drop terminator, CloneFunctionInto() will immediately crash.
So let's not do that :)
The function extractArgumentsFromModule() was passing a one-based index to,
but replaceFunctionCalls() was expecting a zero-based argument index. This
resulted in assertion errors when reducing function call arguments with
different types. Additionally, the
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D84099
Summary:
I think, this results in much more understandable/readable flow.
At least the original logic was perhaps the most hard thing for me to grasp when taking an initial look on the delta passes.
Reviewers: nickdesaulniers, dblaikie, diegotf, george.burgess.iv
Reviewed By: nickdesaulniers
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D83287
As it can be seen in newly-added (previously-crashing) test-case,
there can be a situation where multiple arguments are used in instr,
and we would schedule the same instruction to be deleted several times,
crashing when trying to delete it the second time.
We could either store WeakVH (done here), or use something set-like.
I think using WeakVH is prevalent in these cases elsewhere.
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.
This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.
This doesn't actually modify StringRef yet, I'll do that in a follow-up.
Fixing a couple of asan-identified bugs
* use of an invalid "Use" iterator after the element was removed
* use of StringRef to Function name after the Function was erased
This reapplies r371567, which was reverted in r371580.
llvm-svn: 371700
Roman Lebedev