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llvm-mirror/test/CodeGen/Hexagon/two-addr-tied-subregs.mir
Bjorn Pettersson bb16824edf [TwoAddressInstructionPass] Replace subregister uses when processing tied operands
Summary:
TwoAddressInstruction pass typically rewrites
  %1:short = foo %0.sub_lo:long
as
  %1:short = COPY %0.sub_lo:long
  %1:short = foo %1:short
when having tied operands.

If there are extra un-tied operands that uses the same reg and
subreg, such as the second and third inputs to fie here:
  %1:short = fie %0.sub_lo:long, %0.sub_hi:long, %0.sub_lo:long
then there was a bug which replaced the register %0 also for
the un-tied operand, but without changing the subregister indices.
So we used to get:
  %1:short = COPY %0.sub_lo:long
  %1:short = fie %1, %1.sub_hi:short, %1.sub_lo:short
With this fix we instead get:
  %1:short = COPY %0.sub_lo:long
  %1:short = fie %1, %0.sub_hi:long, %1

Reviewers: arsenm, JesperAntonsson, kparzysz, MatzeB

Reviewed By: MatzeB

Subscribers: bjope, kparzysz, wdng, llvm-commits

Differential Revision: https://reviews.llvm.org/D36224

llvm-svn: 344492
2018-10-15 08:36:03 +00:00

57 lines
1.7 KiB
YAML

# RUN: llc -march hexagon -run-pass livevars -run-pass twoaddressinstruction -verify-machineinstrs -o - %s | FileCheck %s
###############################################################################
---
name: test1
tracksRegLiveness: true
body: |
bb.0.entry:
liveins: $d0
%0:doubleregs = COPY killed $d0
%1:intregs = S2_lsr_i_r_acc %0.isub_lo, %0.isub_lo, 16
...
# Verify that both uses if %0.isub_lo are replaced here.
# (we used to get %1:intregs = S2_lsr_i_r_acc %1, %1.isub_lo, 16)
#
# CHECK-LABEL: name: test1
# CHECK: bb.0.entry:
# CHECK: %0:doubleregs = COPY killed $d0
# CHECK-NEXT: %1:intregs = COPY killed %0.isub_lo
# CHECK-NEXT: %1:intregs = S2_lsr_i_r_acc %1, %1, 16
###############################################################################
---
name: test2
tracksRegLiveness: true
body: |
bb.0.entry:
liveins: $d0
%0:doubleregs = COPY killed $d0
%1:intregs = S2_lsr_i_r_acc %0.isub_lo, %0.isub_hi, 16
...
# Verify that the use of %0.isub_hi isn't replaced here.
# (we used to get %1:intregs = S2_lsr_i_r_acc %1, %1.isub_hi, 16)
#
# We also used to get an incorrect "killed" for %0 in the second COPY.
# So we verify that we do not get machine verifier complaints here.
# An improvement could be to get a "killed" attribute on the last
# use of %0.isub_hi, but we do not need it for the IR to be valid.
#
# CHECK-LABEL: name: test2
# CHECK: bb.0.entry:
# CHECK: %0:doubleregs = COPY killed $d0
# CHECK-NEXT: %1:intregs = COPY %0.isub_lo
# CHECK-NEXT: %1:intregs = S2_lsr_i_r_acc %1, %0.isub_hi, 16
###############################################################################