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llvm-mirror/test/CodeGen/AMDGPU/smrd-vccz-bug.ll
Jay Foad b4c888fa24 [AMDGPU] Simplify VCCZ bug handling
Summary:
VCCZBugHandledSet was used to make sure we don't apply the same
workaround more than once to a single cbranch instruction, but it's not
necessary because the workaround involves inserting an s_waitcnt
instruction, which is enough for subsequent iterations to detect that no
further workaround is necessary.

Also beef up the test case to check that the workaround was only applied
once. I have also manually verified that the test still passes even if I
hack the big do-while loop in runOnMachineFunction to run a minimum of
five iterations.

Subscribers: arsenm, kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69621
2019-10-30 17:09:07 +00:00

50 lines
1.6 KiB
LLVM

; RUN: llc -march=amdgcn -mcpu=verde -verify-machineinstrs < %s | FileCheck -check-prefix=GCN -check-prefix=VCCZ-BUG %s
; RUN: llc -march=amdgcn -mcpu=bonaire -verify-machineinstrs < %s | FileCheck -check-prefix=GCN -check-prefix=VCCZ-BUG %s
; RUN: llc -march=amdgcn -mcpu=tonga -mattr=-flat-for-global -verify-machineinstrs < %s | FileCheck -check-prefix=GCN %s
; GCN-FUNC: {{^}}vccz_workaround:
; GCN: s_load_dword s{{[0-9]+}}, s[{{[0-9]+:[0-9]+}}], 0x0
; GCN: v_cmp_neq_f32_e64 {{[^,]*}}, s{{[0-9]+}}, 0{{$}}
; VCCZ-BUG: s_waitcnt lgkmcnt(0)
; VCCZ-BUG: s_mov_b64 vcc, vcc
; GCN-NOT: s_mov_b64 vcc, vcc
; GCN: s_cbranch_vccnz [[EXIT:[0-9A-Za-z_]+]]
; GCN: buffer_store_dword
; GCN: [[EXIT]]:
; GCN: s_endpgm
define amdgpu_kernel void @vccz_workaround(i32 addrspace(4)* %in, i32 addrspace(1)* %out, float %cond) {
entry:
%cnd = fcmp oeq float 0.0, %cond
%sgpr = load volatile i32, i32 addrspace(4)* %in
br i1 %cnd, label %if, label %endif
if:
store i32 %sgpr, i32 addrspace(1)* %out
br label %endif
endif:
ret void
}
; GCN-FUNC: {{^}}vccz_noworkaround:
; GCN: v_cmp_neq_f32_e32 vcc, 0, v{{[0-9]+}}
; GCN-NOT: s_waitcnt lgkmcnt(0)
; GCN-NOT: s_mov_b64 vcc, vcc
; GCN: s_cbranch_vccnz [[EXIT:[0-9A-Za-z_]+]]
; GCN: buffer_store_dword
; GCN: [[EXIT]]:
; GCN: s_endpgm
define amdgpu_kernel void @vccz_noworkaround(float addrspace(1)* %in, float addrspace(1)* %out) {
entry:
%vgpr = load volatile float, float addrspace(1)* %in
%cnd = fcmp oeq float 0.0, %vgpr
br i1 %cnd, label %if, label %endif
if:
store float %vgpr, float addrspace(1)* %out
br label %endif
endif:
ret void
}