Commit Graph

6 Commits

Author SHA1 Message Date
Volkan Keles da5578c5d0 [GlobalISel] Fix the artifact combiner to fold G_IMPLICIT_DEF properly
Summary:
GlobalISel generates incorrect code because the legalizer artifact
combiner assumes `G_[SZ]EXT (G_IMPLICIT_DEF)` is equivalent to
`G_IMPLICIT_DEF `.

Replace `G_[SZ]EXT (G_IMPLICIT_DEF)` with 0 because the top bits
will be 0 for G_ZEXT and 0/1 for the G_SEXT.

Reviewers: aditya_nandakumar, dsanders, aemerson, javed.absar

Reviewed By: aditya_nandakumar

Subscribers: rovka, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D52996

llvm-svn: 344163
2018-10-10 18:01:48 +00:00
Daniel Sanders acc008cb0c [globalisel] Remove redundant -global-isel option from tests that use -run-pass. NFC
As Roman Tereshin pointed out in https://reviews.llvm.org/D45541, the
-global-isel option is redundant when -run-pass is given. -global-isel sets up
the GlobalISel passes in the pass manager but -run-pass skips that entirely and
configures it's own pipeline.

llvm-svn: 331603
2018-05-05 21:19:59 +00:00
Daniel Sanders 27fe8a5011 [globalisel][legalizerinfo] Add support for legalization based on the MachineMemOperand
Summary:
Currently only the memory size is supported but others can be added as
needed.

narrowScalar for G_LOAD and G_STORE now correctly update the
MachineMemOperand and will refuse to legalize atomics since those need more
careful expansions to maintain atomicity.

Reviewers: ab, aditya_nandakumar, bogner, rtereshin, aemerson, javed.absar

Reviewed By: aemerson

Subscribers: aemerson, rovka, kristof.beyls, javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D45466

llvm-svn: 331071
2018-04-27 19:48:53 +00:00
Aditya Nandakumar e6201c8724 [GISel]: Rework legalization algorithm for better elimination of
artifacts along with DCE

Legalization Artifacts are all those insts that are there to make the
type system happy. Currently, the target needs to say all combinations
of extends and truncs are legal and there's no way of verifying that
post legalization, we only have *truly* legal instructions. This patch
changes roughly the legalization algorithm to process all illegal insts
at one go, and then process all truncs/extends that were added to
satisfy the type constraints separately trying to combine trivial cases
until they converge. This has the added benefit that, the target
legalizerinfo can only say which truncs and extends are okay and the
artifact combiner would combine away other exts and truncs.

Updated legalization algorithm to roughly the following pseudo code.

WorkList Insts, Artifacts;
collect_all_insts_and_artifacts(Insts, Artifacts);

do {
  for (Inst in Insts)
         legalizeInstrStep(Inst, Insts, Artifacts);
  for (Artifact in Artifacts)
         tryCombineArtifact(Artifact, Insts, Artifacts);
} while(!Insts.empty());

Also, wrote a simple wrapper equivalent to SetVector, except for
erasing, it avoids moving all elements over by one and instead just
nulls them out.

llvm-svn: 318210
2017-11-14 22:42:19 +00:00
Justin Bogner 6c452834a1 MIR: Print the register class or bank in vreg defs
This updates the MIRPrinter to include the regclass when printing
virtual register defs, which is already valid syntax for the
parser. That is, given 64 bit %0 and %1 in a "gpr" regbank,

  %1(s64) = COPY %0(s64)

would now be written as

  %1:gpr(s64) = COPY %0(s64)

While this change alone introduces a bit of redundancy with the
registers block, it allows us to update the tests to be more concise
and understandable and brings us closer to being able to remove the
registers block completely.

Note: We generally only print the class in defs, but there is one
exception. If there are uses without any defs whatsoever, we'll print
the class on all uses. I'm not completely convinced this comes up in
meaningful machine IR, but for now the MIRParser and MachineVerifier
both accept that kind of stuff, so we don't want to have a situation
where we can print something we can't parse.

llvm-svn: 316479
2017-10-24 18:04:54 +00:00
Igor Breger 47be5fbbe9 [GlobalISel][X86] Support G_IMPLICIT_DEF.
Summary: Support G_IMPLICIT_DEF.

Reviewers: zvi, guyblank, t.p.northover

Reviewed By: guyblank

Subscribers: rovka, llvm-commits, kristof.beyls

Differential Revision: https://reviews.llvm.org/D36733

llvm-svn: 311633
2017-08-24 07:06:27 +00:00