[PATCH] D123860: GlobalISel: Relax handling of G_ASSERT_* with source register classes

[Matt Arsenault via Phabricator via llvm-commits]

arsenm created this revision.
arsenm added reviewers: aemerson, paquette, qcolombet.
Herald added subscribers: kerbowa, hiraditya, tpr, rovka, jvesely.
Herald added a project: All.
arsenm requested review of this revision.
Herald added a subscriber: wdng.
Herald added a project: LLVM.

The most common situation where G_ASSERT_ZEXT appears for AMDGPU is a
copy from a physical register, which happens to use set the actual
register class on the virtual register. After copy coalescing, the
assert's source operand had a vreg with a set class. The verifier was
strictly rejecting cases where the set class/bank weren't an exact
match. Additionally, RegBankSelect was also expecting a register bank
to be set on the register, not a class.

      

This is much stricter than regular copies so relax this behavior. This
now allows these 2 cases:

      

1. Source register has either class or bank, and the result does not
2. Source register has a register class, and the result is a register with a matching bank.

This should avoid needing some kind of special handling to avoid
violating this constraint when folding copies.


https://reviews.llvm.org/D123860

Files:
  llvm/lib/CodeGen/GlobalISel/RegBankSelect.cpp
  llvm/lib/CodeGen/MachineVerifier.cpp
  llvm/test/CodeGen/AMDGPU/GlobalISel/regbankselect-assert-zext.mir
  llvm/test/MachineVerifier/test_g_assert_sext_register_bank_class.mir
  llvm/test/MachineVerifier/test_g_assert_zext_register_bank_class.mir

-------------- next part --------------
A non-text attachment was scrubbed...
Name: D123860.423121.patch
Type: text/x-patch
Size: 10975 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220415/6b53b3c6/attachment.bin>