>>
>
> It doesn't matter in terms of semantics: because AnalyzeGlobal
> returned false, we're guaranteed the address of the global is never
> taken. I wouldn't be surprised if we end up generating invalid IR in
> some cases, though, because of the semantics of replaceAllUsesWith.
> Do you have a testcase that breaks?
>
>
The problem is replaceAllUsesWith asserts for type mismatch here. Try attached .bc with llvm-ld.
assert(New->getType() == getType() &&
"replaceAllUses of value with new value of different type!");
Since stack is always on address space zero, I don't think that type of GV in a different address space is ever going to match.
The other way is to allow replaceAllUsesWith to ignore address spaces while comparing types. (do we have a way to do that ?).
But then such an optimization may fail the entire idea of user wanting to place a variable into different memory space. The original idea of user might be to save on the stack space (data memory) and hence he asked the variable to be placed into different memory space (program memory). So the best bet here is to deny this optimization by checking
GV->getType()->getAddressSpace() == 0.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73605 91177308-0d34-0410-b5e6-96231b3b80d8
is that, for functions whose bodies are entirely guarded by an if-statement, it
can be profitable to pull the test out of the callee and into the caller.
This code has had some cursory testing, but still has a number of known issues
on the LLVM test suite.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73338 91177308-0d34-0410-b5e6-96231b3b80d8
the relationship with MergeFunctions.cpp's isEquivalentOperation,
and make a trivial code reordering so that the two functions are
easier to compare.
Fix the name of Instruction::isSameOperationAs in MergeFunction.cpp's
isEquivalentOperation's comment, and fix a nearby 80-column violation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73241 91177308-0d34-0410-b5e6-96231b3b80d8
points to while analyzing all other fields.
Use FoldingSetNodeID to produce a good hash. This dramatically decreases run
times.
Emit thunks. This means that it can look at all functions regardless of what
the linkage is or if the address is taken, but unfortunately some small
functions can be even shorter than the thunk because our backend doesn't yet
realize it can just turn these into jumps. This means that this pass will
pessimize code on average.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73222 91177308-0d34-0410-b5e6-96231b3b80d8
identical function ConstantIsDead() to SafeToDestroyConstant(), to
emphasise the connection with Constant::destroyConstant().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73149 91177308-0d34-0410-b5e6-96231b3b80d8
and it wasn't generating calls through @PLT for these functions.
hasLocalLinkage() is now false for available_externally,
I attempted to fix the inliner and dce to handle available_externally properly.
It passed make check.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72328 91177308-0d34-0410-b5e6-96231b3b80d8
the readnone. Since MallocInst is scheduled for deletion
it doesn't seem worth doing anything more subtle, such as
having mayWriteToMemory return true for MallocInst.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71077 91177308-0d34-0410-b5e6-96231b3b80d8
the inliner; prevents nondeterministic behavior
when the same address is reallocated.
Don't build call graph nodes for debug intrinsic calls;
they're useless, and there were typically a lot of them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67311 91177308-0d34-0410-b5e6-96231b3b80d8
changes.
For InvokeInst now all arguments begin at op_begin().
The Callee, Cont and Fail are now faster to get by
access relative to op_end().
This patch introduces some temporary uglyness in CallSite.
Next I'll bring CallInst up to a similar scheme and then
the uglyness will magically vanish.
This patch also exposes all the reliance of the libraries
on InvokeInst's operand ordering. I am thinking of taking
care of that too.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66920 91177308-0d34-0410-b5e6-96231b3b80d8
and extern_weak_odr. These are the same as the non-odr versions,
except that they indicate that the global will only be overridden
by an *equivalent* global. In C, a function with weak linkage can
be overridden by a function which behaves completely differently.
This means that IP passes have to skip weak functions, since any
deductions made from the function definition might be wrong, since
the definition could be replaced by something completely different
at link time. This is not allowed in C++, thanks to the ODR
(One-Definition-Rule): if a function is replaced by another at
link-time, then the new function must be the same as the original
function. If a language knows that a function or other global can
only be overridden by an equivalent global, it can give it the
weak_odr linkage type, and the optimizers will understand that it
is alright to make deductions based on the function body. The
code generators on the other hand map weak and weak_odr linkage
to the same thing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66339 91177308-0d34-0410-b5e6-96231b3b80d8
to find a tiny mouse hole to squeeze through, it struck
me that globals without a name can be considered internal
since they can't be referenced from outside the current
module. This patch makes GlobalOpt give them internal
linkage. Also done for aliases even though they always
have names, since in my opinion anonymous aliases should
be allowed for consistency with global variables and
functions. So if that happens one day, this code is ready!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66267 91177308-0d34-0410-b5e6-96231b3b80d8
If non constant local GV named A is used by a constant local GV named B (e.g. llvm.dbg.variable) and B is not used by anyone else then eliminate A as well as B.
In other words, debug info should not interfere in removal of unused GV.
--This life, and those below, will be ignored--
M test/Transforms/GlobalOpt/2009-03-03-dbg.ll
M lib/Transforms/IPO/GlobalOpt.cpp
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66167 91177308-0d34-0410-b5e6-96231b3b80d8
