src/llvm-project/llvm/test/CodeGen/AMDGPU/coalescer-early-clobber-subreg.mir

# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
# RUN: llc -march=amdgcn -verify-machineinstrs -run-pass=register-coalescer -o - %s | FileCheck %s

# Test used to crash with message:
# JoinVals::computeAssignment(unsigned int, (anonymous namespace)::JoinVals &): Assertion `Assignments[ValNo] != -1 && "Bad recursion?"' failed.

# The issue was with processing two operands are parts of the same reg and are
# used in the same instruction (e.g. inline asm): first is "def early-clobber",
# while the other is just "def".
# Register coalescer ran in bad recursion if the early clobbered subreg is
# second in the following sequence of COPYs.

---
name:            foo1
tracksRegLiveness: true
body:             |
  bb.0:
    liveins: $vgpr0_vgpr1

    ; CHECK-LABEL: name: foo1
    ; CHECK: liveins: $vgpr0_vgpr1
    ; CHECK-NEXT: {{  $}}
    ; CHECK-NEXT: INLINEASM &"", 0 /* attdialect */, 1835018 /* regdef:SRegOrLds_32 */, def undef %2.sub0, 1835019 /* regdef-ec:SRegOrLds_32 */, def undef early-clobber %2.sub1
    ; CHECK-NEXT: FLAT_STORE_DWORDX2 $vgpr0_vgpr1, %2, 0, 0, implicit $exec, implicit $flat_scr :: (store (s64))
    ; CHECK-NEXT: S_ENDPGM 0
    INLINEASM &"", 0 /* attdialect */, 1835018 /* regdef:VGPR_32 */, def %0:vgpr_32, 1835019 /* regdef-ec:VGPR_32 */, def early-clobber %1:vgpr_32
    undef %2.sub0:vreg_64 = COPY killed %0
    %2.sub1:vreg_64 = COPY killed %1
    FLAT_STORE_DWORDX2 killed $vgpr0_vgpr1, killed %2, 0, 0, implicit $exec, implicit $flat_scr :: (store (s64))
    S_ENDPGM 0

...

---
name:            foo2
tracksRegLiveness: true
body:             |
  bb.0:
    liveins: $vgpr0_vgpr1

    ; CHECK-LABEL: name: foo2
    ; CHECK: liveins: $vgpr0_vgpr1
    ; CHECK-NEXT: {{  $}}
    ; CHECK-NEXT: INLINEASM &"", 0 /* attdialect */, 1835019 /* regdef-ec:SRegOrLds_32 */, def undef early-clobber %2.sub1, 1835018 /* regdef:SRegOrLds_32 */, def undef %2.sub0
    ; CHECK-NEXT: FLAT_STORE_DWORDX2 $vgpr0_vgpr1, %2, 0, 0, implicit $exec, implicit $flat_scr :: (store (s64))
    ; CHECK-NEXT: S_ENDPGM 0
    INLINEASM &"", 0 /* attdialect */, 1835019 /* regdef-ec:VGPR_32 */, def early-clobber %1:vgpr_32, 1835018 /* regdef:VGPR_32 */, def %0:vgpr_32
    undef %2.sub0:vreg_64 = COPY killed %0
    %2.sub1:vreg_64 = COPY killed %1
    FLAT_STORE_DWORDX2 killed $vgpr0_vgpr1, killed %2, 0, 0, implicit $exec, implicit $flat_scr :: (store (s64))
    S_ENDPGM 0

...

---
name:            foo3
tracksRegLiveness: true
body:             |
  bb.0:
    liveins: $vgpr0_vgpr1

    ; CHECK-LABEL: name: foo3
    ; CHECK: liveins: $vgpr0_vgpr1
    ; CHECK-NEXT: {{  $}}
    ; CHECK-NEXT: INLINEASM &"", 0 /* attdialect */, 1835018 /* regdef:SRegOrLds_32 */, def undef %2.sub0, 1835019 /* regdef-ec:SRegOrLds_32 */, def undef early-clobber %2.sub1
    ; CHECK-NEXT: FLAT_STORE_DWORDX2 $vgpr0_vgpr1, %2, 0, 0, implicit $exec, implicit $flat_scr :: (store (s64))
    ; CHECK-NEXT: S_ENDPGM 0
    INLINEASM &"", 0 /* attdialect */, 1835018 /* regdef:VGPR_32 */, def %1:vgpr_32, 1835019 /* regdef-ec:VGPR_32 */, def early-clobber %0:vgpr_32
    undef %2.sub0:vreg_64 = COPY killed %1
    %2.sub1:vreg_64 = COPY killed %0
    FLAT_STORE_DWORDX2 killed $vgpr0_vgpr1, killed %2, 0, 0, implicit $exec, implicit $flat_scr :: (store (s64))
    S_ENDPGM 0

...

---
name:            foo4
tracksRegLiveness: true
body:             |
  bb.0:
    liveins: $vgpr0_vgpr1

    ; CHECK-LABEL: name: foo4
    ; CHECK: liveins: $vgpr0_vgpr1
    ; CHECK-NEXT: {{  $}}
    ; CHECK-NEXT: INLINEASM &"", 0 /* attdialect */, 1835019 /* regdef-ec:SRegOrLds_32 */, def undef early-clobber %2.sub1, 1835018 /* regdef:SRegOrLds_32 */, def undef %2.sub0
    ; CHECK-NEXT: FLAT_STORE_DWORDX2 $vgpr0_vgpr1, %2, 0, 0, implicit $exec, implicit $flat_scr :: (store (s64))
    ; CHECK-NEXT: S_ENDPGM 0
    INLINEASM &"", 0 /* attdialect */, 1835019 /* regdef-ec:VGPR_32 */, def early-clobber %0:vgpr_32, 1835018 /* regdef:VGPR_32 */, def %1:vgpr_32
    undef %2.sub0:vreg_64 = COPY killed %1
    %2.sub1:vreg_64 = COPY killed %0
    FLAT_STORE_DWORDX2 killed $vgpr0_vgpr1, killed %2, 0, 0, implicit $exec, implicit $flat_scr :: (store (s64))
    S_ENDPGM 0

...