7a98f084c4
Currently, the custom SGPR spill lowering pass spills SGPRs into physical VGPR lanes and the remaining VGPRs are used by regalloc for vector regclass allocation. This imposes many restrictions that we ended up with unsuccessful SGPR spilling when there won't be enough VGPRs and we are forced to spill the leftover into memory during PEI. The custom spill handling during PEI has many edge cases and often breaks the compiler time to time. This patch implements spilling SGPRs into virtual VGPR lanes. Since we now split the register allocation for SGPRs and VGPRs, the virtual registers introduced for the spill lanes would get allocated automatically in the subsequent regalloc invocation for VGPRs. Spill to virtual registers will always be successful, even in the high-pressure situations, and hence it avoids most of the edge cases during PEI. We are now left with only the custom SGPR spills during PEI for special registers like the frame pointer which is an unproblematic case. Differential Revision: https://reviews.llvm.org/D124196
61 lines
2.4 KiB
LLVM
61 lines
2.4 KiB
LLVM
; RUN: llc -march=amdgcn -mcpu=fiji -mattr=-flat-for-global -amdgpu-sroa=0 -verify-machineinstrs < %s | FileCheck -enable-var-scope -check-prefix=GCN %s
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; RUN: llc -march=amdgcn -mcpu=hawaii -amdgpu-sroa=0 -verify-machineinstrs < %s | FileCheck -enable-var-scope -check-prefix=GCN %s
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; RUN: llc -march=amdgcn -mcpu=gfx900 -mattr=-flat-for-global -amdgpu-sroa=0 -verify-machineinstrs < %s | FileCheck -enable-var-scope -check-prefix=GCN %s
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; Test calls when called by other callable functions rather than
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; kernels.
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declare void @external_void_func_i32(i32) #0
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; GCN-LABEL: {{^}}test_func_call_external_void_func_i32_imm:
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; GCN: s_waitcnt
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; Spill CSR VGPR used for SGPR spilling
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; GCN: s_mov_b32 [[FP_SCRATCH_COPY:s[0-9]+]], s33
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; GCN-NEXT: s_mov_b32 s33, s32
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; GCN-NEXT: s_or_saveexec_b64 [[COPY_EXEC0:s\[[0-9]+:[0-9]+\]]], -1{{$}}
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; GCN-NEXT: buffer_store_dword v40, off, s[0:3], s33 ; 4-byte Folded Spill
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; GCN-NEXT: s_mov_b64 exec, [[COPY_EXEC0]]
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; GCN-DAG: v_writelane_b32 v40, [[FP_SCRATCH_COPY]], 2
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; GCN-DAG: v_writelane_b32 v40, s30, 0
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; GCN-DAG: v_writelane_b32 v40, s31, 1
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; GCN: s_swappc_b64
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; GCN: v_readlane_b32 s31, v40, 1
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; GCN: v_readlane_b32 s30, v40, 0
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; GCN-NEXT: v_readlane_b32 [[FP_SCRATCH_COPY:s[0-9]+]], v40, 2
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; GCN: s_or_saveexec_b64 [[COPY_EXEC1:s\[[0-9]+:[0-9]+\]]], -1{{$}}
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; GCN-NEXT: buffer_load_dword v40, off, s[0:3], s33 ; 4-byte Folded Reload
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; GCN-NEXT: s_mov_b64 exec, [[COPY_EXEC1]]
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; GCN-NEXT: s_addk_i32 s32, 0xfc00
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; GCN-NEXT: s_mov_b32 s33, [[FP_SCRATCH_COPY]]
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; GCN-NEXT: s_waitcnt vmcnt(0)
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; GCN-NEXT: s_setpc_b64 s[30:31]
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define void @test_func_call_external_void_func_i32_imm() #0 {
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call void @external_void_func_i32(i32 42)
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ret void
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}
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; GCN-LABEL: {{^}}test_func_call_external_void_func_i32_imm_stack_use:
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; GCN: s_waitcnt
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; GCN: s_mov_b32 s33, s32
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; GCN-DAG: s_addk_i32 s32, 0x1400{{$}}
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; GCN-DAG: buffer_store_dword v{{[0-9]+}}, off, s[0:3], s33 offset:
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; GCN: s_swappc_b64
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; GCN: s_addk_i32 s32, 0xec00{{$}}
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; GCN: s_setpc_b64
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define void @test_func_call_external_void_func_i32_imm_stack_use() #0 {
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%alloca = alloca [16 x i32], align 4, addrspace(5)
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%gep15 = getelementptr inbounds [16 x i32], ptr addrspace(5) %alloca, i32 0, i32 16
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store volatile i32 0, ptr addrspace(5) %alloca
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store volatile i32 0, ptr addrspace(5) %gep15
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call void @external_void_func_i32(i32 42)
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ret void
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}
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attributes #0 = { nounwind }
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attributes #1 = { nounwind readnone }
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attributes #2 = { nounwind noinline }
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