return value as a whole in deadargelim is really not needed now that we simply
rebuild the old return value and actually prevents some canonicalization from
taking place.
This revert stops deadargelim from changing {i32} into i32 for now, but I'll
fix that next.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53609 91177308-0d34-0410-b5e6-96231b3b80d8
return values that are still (partially) live. Instead of updating all uses of
a call instruction after removing some elements, it now just rebuilds the
original struct (With undef gaps where the unused values were) and leaves it to
instcombine to clean this up.
The added testcase still fails currently, but this is due to instcombine which
isn't good enough yet. I will fix that part next.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53608 91177308-0d34-0410-b5e6-96231b3b80d8
only the liveness of partial return values (for functions returning a struct).
This is more explicit to prevent unwanted changes in the return value.
In particular, deadargelim now canonicalizes a function returning {i32} to
returning i32 and {} to void, if the struct returned is not used in its
entirety, but only the single element is used.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53606 91177308-0d34-0410-b5e6-96231b3b80d8
and return values live for those functions. This doesn't change anything yet,
but prepares for the coming commits.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53601 91177308-0d34-0410-b5e6-96231b3b80d8
Rewrite the DeadArgumentElimination pass, to use a more explicit tracking of
dependencies between return values and/or arguments. Also make the handling of
arguments and return values the same.
The pass now looks properly inside returned structs, but only at the first
level (ie, not inside nested structs).
This version fixed a few more bugs and was cleaned up a bit. It now passes all
of LLVM's testing, and should still pass SPEC2006. There is still a minor bug
with regard to returning nested structs. Since there is currently nothing that
emits such IR, I will fix that in a seperate commit (partly because it requires
a non-trivial fix).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53400 91177308-0d34-0410-b5e6-96231b3b80d8
DeadArgumentElimination and assert that the function type does not change if
nothing was changed. This should catch subtle changes in function type that are
not intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52536 91177308-0d34-0410-b5e6-96231b3b80d8
This is a fixed version that no longer uses multimap::equal_range, which
resulted in a pointer invalidation problem.
Also, DAE::InspectedFunctions was not really necessary, so it got removed.
Lastly, this version no longer applies the extra arg hack on functions who did
not have any arguments to start with.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52532 91177308-0d34-0410-b5e6-96231b3b80d8
dependencies between return values and/or arguments. Also make the handling of
arguments and return values the same.
The pass now looks properly inside returned structs, but only at the first
level (ie, not inside nested structs).
Also add a testcase for testing various variations of (multiple) dead rerturn
values.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52459 91177308-0d34-0410-b5e6-96231b3b80d8
time. Sorry for the trouble!
This time, also add a testcase, which I should have done in the first place...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52455 91177308-0d34-0410-b5e6-96231b3b80d8
speaking these are not constant values. However, when a function always returns
one of its arguments, then from the point of view of each caller the return
value is constant (or at least a known value) and can be replaced.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52397 91177308-0d34-0410-b5e6-96231b3b80d8
individually.
Also learn IPConstProp how returning first class aggregates work, in addition
to old style multiple return instructions.
Modify the return-constants testscase to confirm this behaviour.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52396 91177308-0d34-0410-b5e6-96231b3b80d8
the section or the visibility from one global
value to another: copyAttributesFrom. This is
particularly useful for duplicating functions:
previously this was done by explicitly copying
each attribute in turn at each place where a
new function was created out of an old one, with
the result that obscure attributes were regularly
forgotten (like the collector or the section).
Hopefully now everything is uniform and nothing
is forgotten.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51567 91177308-0d34-0410-b5e6-96231b3b80d8
