This patch makes Scalarizer to use poison as insertelement's placeholder.
It contains two changes in Scalarizer.cpp, and the both changes does not change the semantics of the optimized program.
It is because the placeholder value (poison) is already completely hidden by following insertelement instructions.
The first change at visitBitCastInst() creates poison vector of MidTy and consecutively inserts FanIn times,
which is # of elems of MidTy.
The second change at ScalarizerVisitor::finish() creates poison with Op->getType(), and it is filled with
Count insertelements.
The test diffs show that the poison value is never exposed after insertelements.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D93989
Summary:
I'm interested in taking the original C++ input,
for which we currently are stuck with an alloca
and producing roughly the lower IR,
with neither an alloca nor a vector ops:
https://godbolt.org/z/cRRWaJ
For that, as intermediate step, i'd to somehow perform scalarization.
As per @arsenmn suggestion, i'm trying to see if scalarizer can help me
avoid writing a bicycle.
I'm not sure if it's really intentional that variable insert is not handled currently.
If it really is, and is supposed to stay that way (?), i guess i could guard it..
See [[ https://bugs.llvm.org/show_bug.cgi?id=46524 | PR46524 ]].
Reviewers: bjope, cameron.mcinally, arsenm, jdoerfert
Reviewed By: jdoerfert
Subscribers: arphaman, uabelho, wdng, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D82961
Juneyoung Lee