llvm/test/CodeGen/AMDGPU/recursion.ll

   1 ; RUN: sed 's/CODE_OBJECT_VERSION/400/g' %s | llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -verify-machineinstrs | FileCheck %s
   2 ; RUN: sed 's/CODE_OBJECT_VERSION/500/g' %s | llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -verify-machineinstrs | FileCheck -check-prefixes=V5 %s
   3
   4 ; CHECK-LABEL: {{^}}recursive:
   5 ; CHECK: ScratchSize: 16
   6 define void @recursive() {
   7   call void @recursive()
   8   store volatile i32 0, ptr addrspace(1) undef
   9   ret void
  10 }
  11
  12 ; CHECK-LABEL: {{^}}tail_recursive:
  13 ; CHECK: ScratchSize: 0
  14 define void @tail_recursive() {
  15   tail call void @tail_recursive()
  16   ret void
  17 }
  18
  19 define void @calls_tail_recursive() norecurse {
  20   tail call void @tail_recursive()
  21   ret void
  22 }
  23
  24 ; CHECK-LABEL: {{^}}tail_recursive_with_stack:
  25 define void @tail_recursive_with_stack() {
  26   %alloca = alloca i32, addrspace(5)
  27   store volatile i32 0, ptr addrspace(5) %alloca
  28   tail call void @tail_recursive_with_stack()
  29   ret void
  30 }
  31
  32 ; For an arbitrary recursive call, report a large number for unknown stack
  33 ; usage for code object v4 and older
  34 ; CHECK-LABEL: {{^}}calls_recursive:
  35 ; CHECK: .amdhsa_private_segment_fixed_size 16400{{$}}
  36 ;
  37 ; V5-LABEL: {{^}}calls_recursive:
  38 ; V5: .amdhsa_private_segment_fixed_size 0{{$}}
  39 ; V5: .amdhsa_uses_dynamic_stack 1
  40 define amdgpu_kernel void @calls_recursive() {
  41   call void @recursive()
  42   ret void
  43 }
  44
  45 ; Make sure we do not report a huge stack size for tail recursive
  46 ; functions
  47 ; CHECK-LABEL: {{^}}kernel_indirectly_calls_tail_recursive:
  48 ; CHECK: .amdhsa_private_segment_fixed_size 0{{$}}
  49 define amdgpu_kernel void @kernel_indirectly_calls_tail_recursive() {
  50   call void @calls_tail_recursive()
  51   ret void
  52 }
  53
  54 ; TODO: Even though tail_recursive is only called as a tail call, we
  55 ; end up treating it as generally recursive call from the regular call
  56 ; in the kernel.
  57
  58 ; CHECK-LABEL: {{^}}kernel_calls_tail_recursive:
  59 ; CHECK: .amdhsa_private_segment_fixed_size 16384{{$}}
  60 ;
  61 ; V5-LABEL: {{^}}kernel_calls_tail_recursive:
  62 ; V5: .amdhsa_private_segment_fixed_size 0{{$}}
  63 ; V5: .amdhsa_uses_dynamic_stack 1
  64 define amdgpu_kernel void @kernel_calls_tail_recursive() {
  65   call void @tail_recursive()
  66   ret void
  67 }
  68
  69 ; CHECK-LABEL: {{^}}kernel_calls_tail_recursive_with_stack:
  70 ; CHECK: .amdhsa_private_segment_fixed_size 16384{{$}}
  71 ;
  72 ; V5-LABEL: {{^}}kernel_calls_tail_recursive_with_stack:
  73 ; V5: .amdhsa_private_segment_fixed_size 8{{$}}
  74 ; V5: .amdhsa_uses_dynamic_stack 1
  75 define amdgpu_kernel void @kernel_calls_tail_recursive_with_stack() {
  76   call void @tail_recursive_with_stack()
  77   ret void
  78 }
  79
  80 !llvm.module.flags = !{!0}
  81 !0 = !{i32 1, !"amdgpu_code_object_version", i32 CODE_OBJECT_VERSION}