The global constant arguments could be in a different address space
than the first argument, so we have to add another overloaded argument.
This patch was originally made for CHERI LLVM (where globals can be in
address space 200), but it also appears to be useful for in-tree targets
as can be seen from the test diffs.
Differential Revision: https://reviews.llvm.org/D138722
This enhances the base fold from part 1 to allow mapping a
right-shift to an insert index.
Example of translating a middle chunk of the scalar to vector
for either endian:
https://alive2.llvm.org/ce/z/fRXCOZ
This only allows creating an identity shuffle (with optional
shortening/lengthening) because that is considered the safe
baseline for any target (can be inverted if needed). If we
tried this fold with target-specific costs/legality, then we
could do the transform more generally.
Differential Revision: https://reviews.llvm.org/D138873
The first attempt was reverted because a clang test changed
unexpectedly - the file is already marked with a FIXME, so
I just updated it this time to pass.
Original commit message:
This is the main patch for converting a truncated scalar that is
inserted into a vector to bitcast+shuffle. We could go either way
on patterns like this, but this direction will allow collapsing a
pair of these sequences on the motivating example from issue
The patch is split into 3 parts to make it easier to see the
progression of tests diffs. We allow inserting/shuffling into a
different size vector for flexibility, so there are several test
variations. The length-changing is handled by shortening/padding
the shuffle mask with undef elements.
In part 1, handle the basic pattern:
inselt undef, (trunc T), IndexC --> shuffle (bitcast T), IdentityMask
Proof for the endian-dependency behaving as expected:
https://alive2.llvm.org/ce/z/BsA7yC
The TODO items for handling shifts and insert into an arbitrary base
vector value are implemented as follow-ups.
Differential Revision: https://reviews.llvm.org/D138872
This is the main patch for converting a truncated scalar that is
inserted into a vector to bitcast+shuffle. We could go either way
on patterns like this, but this direction will allow collapsing a
pair of these sequences on the motivating example from issue
The patch is split into 3 parts to make it easier to see the
progression of tests diffs. We allow inserting/shuffling into a
different size vector for flexibility, so there are several test
variations. The length-changing is handled by shortening/padding
the shuffle mask with undef elements.
In part 1, handle the basic pattern:
inselt undef, (trunc T), IndexC --> shuffle (bitcast T), IdentityMask
Proof for the endian-dependency behaving as expected:
https://alive2.llvm.org/ce/z/BsA7yC
The TODO items for handling shifts and insert into an arbitrary base
vector value are implemented as follow-ups.
Differential Revision: https://reviews.llvm.org/D138872
Should cover most of the tests for GVN, GVNHoist, GVNSink, GlobalOpt,
GlobalSplit, InstCombine, Reassociate, SROA and TailCallElim that
had not been updated earlier.
We were checking for a desirable integer type even when there
is no shift in the transform. This is unnecessary since we
are truncating directly to the destination type.
This removes an extractelt in more cases and seems to make the
canonicalization more uniform overall. There's still a potential
difference between patterns that need a shift vs. trunc-only.
I'm not sure if that is worth keeping at this point, but it can
be adjusted in another step (assuming this change does not cause
trouble).
In the most basic case where I noticed this, we missed a fold
that would have completely removed vector ops from a pattern
like:
https://alive2.llvm.org/ce/z/y4Qdte
