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llvm-mirror/test/CodeGen/AMDGPU/call-waw-waitcnt.mir
Austin Kerbow 8f662721b9 AMDGPU: Avoid overwriting saved PC
Summary:
An outstanding load with same destination sgpr as call could cause PC to be
updated with junk value on return.

Reviewers: arsenm, rampitec

Reviewed By: arsenm

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69474
2019-10-28 10:02:22 -07:00

54 lines
2.5 KiB
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# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
# RUN: llc -march=amdgcn -mcpu=gfx900 -verify-machineinstrs -run-pass=si-insert-waitcnts %s -o - | FileCheck -check-prefix=GCN %s
# $sgpr30_sgpr31 will hold the return address. We need a waitcnt before SI_CALL so
# that the return address is not clobbered in the callee by the outstanding load.
--- |
define amdgpu_kernel void @call_waw_waitcnt() #0 {
%1 = call i32 @func()
ret void
}
declare hidden i32 @func() #0
attributes #0 = { nounwind }
...
---
name: call_waw_waitcnt
tracksRegLiveness: true
body: |
bb.0:
liveins: $sgpr4_sgpr5, $sgpr7, $sgpr0_sgpr1_sgpr2_sgpr3
; GCN-LABEL: name: call_waw_waitcnt
; GCN: liveins: $sgpr4_sgpr5, $sgpr7, $sgpr0_sgpr1_sgpr2_sgpr3
; GCN: S_WAITCNT 0
; GCN: $sgpr30_sgpr31 = S_LOAD_DWORDX2_IMM $sgpr4_sgpr5, 0, 0, 0
; GCN: $sgpr33 = S_MOV_B32 killed $sgpr7
; GCN: $flat_scr_lo = S_ADD_U32 killed $sgpr4, $sgpr33, implicit-def $scc
; GCN: $flat_scr_hi = S_ADDC_U32 killed $sgpr5, 0, implicit-def $scc, implicit killed $scc
; GCN: BUNDLE implicit-def $sgpr4_sgpr5, implicit-def $sgpr4, implicit-def $sgpr5, implicit-def $scc {
; GCN: $sgpr4_sgpr5 = S_GETPC_B64
; GCN: $sgpr4 = S_ADD_U32 internal $sgpr4, target-flags(amdgpu-rel32-lo) @func + 4, implicit-def $scc
; GCN: $sgpr5 = S_ADDC_U32 internal $sgpr5, target-flags(amdgpu-rel32-hi) @func + 4, implicit-def $scc, implicit internal $scc
; GCN: }
; GCN: $sgpr32 = S_MOV_B32 $sgpr33
; GCN: S_WAITCNT 49279
; GCN: dead $sgpr30_sgpr31 = SI_CALL killed renamable $sgpr4_sgpr5, @func, csr_amdgpu_highregs, implicit $sgpr0_sgpr1_sgpr2_sgpr3, implicit-def dead $vgpr0
; GCN: S_ENDPGM 0
$sgpr30_sgpr31 = S_LOAD_DWORDX2_IMM $sgpr4_sgpr5, 0, 0, 0
$sgpr33 = S_MOV_B32 killed $sgpr7
$flat_scr_lo = S_ADD_U32 killed $sgpr4, $sgpr33, implicit-def $scc
$flat_scr_hi = S_ADDC_U32 killed $sgpr5, 0, implicit-def $scc, implicit killed $scc
BUNDLE implicit-def $sgpr4_sgpr5, implicit-def $sgpr4, implicit-def $sgpr5, implicit-def $scc {
$sgpr4_sgpr5 = S_GETPC_B64
$sgpr4 = S_ADD_U32 internal $sgpr4, target-flags(amdgpu-rel32-lo) @func + 4, implicit-def $scc
$sgpr5 = S_ADDC_U32 internal $sgpr5, target-flags(amdgpu-rel32-hi) @func + 4, implicit-def $scc, implicit internal $scc
}
$sgpr32 = S_MOV_B32 $sgpr33
dead $sgpr30_sgpr31 = SI_CALL killed renamable $sgpr4_sgpr5, @func, csr_amdgpu_highregs, implicit $sgpr0_sgpr1_sgpr2_sgpr3, implicit-def dead $vgpr0
S_ENDPGM 0
...