391bcf8893
Summary: The current StructurizeCFG pass only works for CFG with one exit. AMDGPUUnifyDivergentExitNodes combines multiple "return" blocks and/or "unreachable" blocks to one exit block for the Structurizer to work. However, infinite loop is another kind of special "exit", and if we don't handle it, the case of multiple exits will prevent the structurizer from working. In this work, for each infinite loop, we add a dummy edge to the "return" block, and thus the AMDGPUUnifyDivergentExitNodes pass will work with infinite loops. This will make CFG with infinite loops be structurized. Reviewer: nhaehnle Differential Revision: https://reviews.llvm.org/D46340 llvm-svn: 332625
125 lines
3.6 KiB
LLVM
125 lines
3.6 KiB
LLVM
; RUN: llc -march=amdgcn -verify-machineinstrs < %s | FileCheck -check-prefix=GCN %s
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; RUN: llc -march=amdgcn -verify-machineinstrs -O0 < %s
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; GCN-LABEL: {{^}}test_loop:
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; GCN: s_and_b64 vcc, exec, -1
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; GCN: [[LABEL:BB[0-9+]_[0-9]+]]: ; %for.body{{$}}
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; GCN: ds_read_b32
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; GCN: ds_write_b32
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; GCN: s_cbranch_vccnz [[LABEL]]
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; GCN: s_endpgm
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define amdgpu_kernel void @test_loop(float addrspace(3)* %ptr, i32 %n) nounwind {
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entry:
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%cmp = icmp eq i32 %n, -1
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br i1 %cmp, label %for.exit, label %for.body
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for.exit:
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ret void
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for.body:
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%indvar = phi i32 [ %inc, %for.body ], [ 0, %entry ]
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%tmp = add i32 %indvar, 32
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%arrayidx = getelementptr float, float addrspace(3)* %ptr, i32 %tmp
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%vecload = load float, float addrspace(3)* %arrayidx, align 4
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%add = fadd float %vecload, 1.0
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store float %add, float addrspace(3)* %arrayidx, align 8
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%inc = add i32 %indvar, 1
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br label %for.body
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}
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; GCN-LABEL: @loop_const_true
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; GCN: [[LABEL:BB[0-9+]_[0-9]+]]:
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; GCN: ds_read_b32
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; GCN: ds_write_b32
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; GCN: s_branch [[LABEL]]
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define amdgpu_kernel void @loop_const_true(float addrspace(3)* %ptr, i32 %n) nounwind {
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entry:
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br label %for.body
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for.exit:
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ret void
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for.body:
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%indvar = phi i32 [ %inc, %for.body ], [ 0, %entry ]
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%tmp = add i32 %indvar, 32
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%arrayidx = getelementptr float, float addrspace(3)* %ptr, i32 %tmp
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%vecload = load float, float addrspace(3)* %arrayidx, align 4
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%add = fadd float %vecload, 1.0
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store float %add, float addrspace(3)* %arrayidx, align 8
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%inc = add i32 %indvar, 1
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br i1 true, label %for.body, label %for.exit
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}
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; GCN-LABEL: {{^}}loop_const_false:
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; GCN-NOT: s_branch
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; GCN: s_endpgm
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define amdgpu_kernel void @loop_const_false(float addrspace(3)* %ptr, i32 %n) nounwind {
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entry:
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br label %for.body
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for.exit:
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ret void
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; XXX - Should there be an S_ENDPGM?
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for.body:
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%indvar = phi i32 [ %inc, %for.body ], [ 0, %entry ]
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%tmp = add i32 %indvar, 32
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%arrayidx = getelementptr float, float addrspace(3)* %ptr, i32 %tmp
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%vecload = load float, float addrspace(3)* %arrayidx, align 4
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%add = fadd float %vecload, 1.0
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store float %add, float addrspace(3)* %arrayidx, align 8
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%inc = add i32 %indvar, 1
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br i1 false, label %for.body, label %for.exit
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}
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; GCN-LABEL: {{^}}loop_const_undef:
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; GCN-NOT: s_branch
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; GCN: s_endpgm
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define amdgpu_kernel void @loop_const_undef(float addrspace(3)* %ptr, i32 %n) nounwind {
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entry:
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br label %for.body
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for.exit:
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ret void
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; XXX - Should there be an s_endpgm?
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for.body:
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%indvar = phi i32 [ %inc, %for.body ], [ 0, %entry ]
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%tmp = add i32 %indvar, 32
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%arrayidx = getelementptr float, float addrspace(3)* %ptr, i32 %tmp
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%vecload = load float, float addrspace(3)* %arrayidx, align 4
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%add = fadd float %vecload, 1.0
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store float %add, float addrspace(3)* %arrayidx, align 8
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%inc = add i32 %indvar, 1
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br i1 undef, label %for.body, label %for.exit
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}
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; GCN-LABEL: {{^}}loop_arg_0:
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; GCN: v_and_b32_e32 v{{[0-9]+}}, 1, v{{[0-9]+}}
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; GCN: v_cmp_eq_u32{{[^,]*}}, 1,
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; GCN: [[LOOPBB:BB[0-9]+_[0-9]+]]
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; GCN: s_add_i32 s{{[0-9]+}}, s{{[0-9]+}}, 0x80
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; GCN: s_add_i32 s{{[0-9]+}}, s{{[0-9]+}}, 4
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; GCN: s_cbranch_vccnz [[LOOPBB]]
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; GCN-NEXT: ; %bb.2
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; GCN-NEXT: s_endpgm
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define amdgpu_kernel void @loop_arg_0(float addrspace(3)* %ptr, i32 %n, i1 %cond) nounwind {
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entry:
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br label %for.body
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for.exit:
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ret void
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for.body:
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%indvar = phi i32 [ %inc, %for.body ], [ 0, %entry ]
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%tmp = add i32 %indvar, 32
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%arrayidx = getelementptr float, float addrspace(3)* %ptr, i32 %tmp
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%vecload = load float, float addrspace(3)* %arrayidx, align 4
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%add = fadd float %vecload, 1.0
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store float %add, float addrspace(3)* %arrayidx, align 8
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%inc = add i32 %indvar, 1
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br i1 %cond, label %for.body, label %for.exit
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}
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