llvm/test/CodeGen/AMDGPU/regalloc-sgpr128-partial-def.mir

# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -verify-machineinstrs --stress-regalloc=2 -start-before=greedy -stop-after=virtregrewriter \
# RUN:   %s -o - | FileCheck %s

# Test that S_MOV_B64 rematerialization is shrunk to S_MOV_B32 when only a
# single 32-bit subreg of the defined value is used at the remat point.

# CHECK-LABEL: name: remat_shrink_s_mov_b64
---
name: remat_shrink_s_mov_b64
tracksRegLiveness: true
body: |
  bb.0:
    liveins: $sgpr8_sgpr9
    %0:sreg_64_xexec = COPY $sgpr8_sgpr9

    ; 0x0000002A_00000539: Lo_32 = 1337, Hi_32 = 42
    undef %1.sub0_sub1:sgpr_128 = S_MOV_B64 180388627769
    ; 0x00000007_00000065: Lo_32 = 101, Hi_32 = 7
    undef %2.sub0_sub1:sgpr_128 = S_MOV_B64 30064771173
    %2.sub2_sub3:sgpr_128 = S_MOV_B64 2
    undef %3.sub2_sub3:sgpr_128 = S_MOV_B64 30064771173
    undef %4.sub2_sub3:sgpr_128 = S_MOV_B64 180388627769
    undef %5.sub0_sub1:sgpr_128 = S_MOV_B64 180388627769
    %6:sreg_64 = S_MOV_B64_IMM_PSEUDO 65536
    S_NOP 0, implicit %1.sub0
    S_NOP 0, implicit %1.sub1

    ; CHECK: S_NOP 0, implicit-def $sgpr0_sgpr1
    S_NOP 0, implicit-def $sgpr0_sgpr1, implicit-def $sgpr2_sgpr3, implicit-def $sgpr4_sgpr5, implicit-def $sgpr6_sgpr7

    ; %2: uses both sub0 and sub1 - no shrink expected.
    S_NOP 0, implicit %2.sub0
    S_NOP 0, implicit %2.sub1

    ; %1: both lanes used after barrier, rematerialized as S_MOV_B64, not shrunk.
    ; CHECK: renamable $[[REG1LO:sgpr[0-9]+]]_[[REG1HI:sgpr[0-9]+]] = S_MOV_B64 180388627769
    ; CHECK-NEXT: S_NOP 0, implicit renamable $[[REG1HI]]
    ; CHECK-NEXT: S_NOP 0, implicit killed renamable $[[REG1LO]]
    S_NOP 0, implicit %1.sub1
    S_NOP 0, implicit %1.sub0

    ; %3: only sub3 used - shrink to S_MOV_B32 with Hi_32(0x0000000700000065) = 7.
    ; CHECK: renamable $[[REG3:sgpr[0-9]+]] = S_MOV_B32 7
    ; CHECK-NEXT: S_NOP 0, implicit renamable $[[REG3]]
    ; CHECK-NEXT: S_NOP 0, implicit killed renamable $[[REG3]]
    S_NOP 0, implicit %3.sub3
    S_NOP 0, implicit %3.sub3

    ; %4: only sub2 used - shrink to S_MOV_B32 with Lo_32(0x0000002A00000539) = 1337.
    ; CHECK: renamable $[[REG4:sgpr[0-9]+]] = S_MOV_B32 1337
    ; CHECK-NEXT: S_NOP 0, implicit killed renamable $[[REG4]]
    S_NOP 0, implicit %4.sub2

    ; %5: sub0_sub1 def, only sub1 used - shrink to S_MOV_B32 with Hi_32(0x0000002A00000539) = 42.
    ; CHECK: renamable $[[REG5:sgpr[0-9]+]] = S_MOV_B32 42
    ; CHECK-NEXT: S_NOP 0, implicit killed renamable $[[REG5]]
    S_NOP 0, implicit %5.sub1

    ; CHECK: renamable $[[REG6:sgpr[0-9]+]] = S_MOV_B32 65536
    ; CHECK-NEXT: S_NOP 0, implicit killed renamable $[[REG6]]
    S_NOP 0, implicit %6.sub0

    ; CHECK: S_ENDPGM 0
    S_ENDPGM 0, implicit %0, implicit %1.sub0
...