llvm-project/llvm/test/CodeGen/AMDGPU/branch-relaxation.ll

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; RUN: llc -march=amdgcn -mcpu=tahiti -verify-machineinstrs -amdgpu-s-branch-bits=4 < %s | FileCheck -enable-var-scope -check-prefix=GCN %s
; FIXME: We should use llvm-mc for this, but we can't even parse our own output.
; See PR33579.
; RUN: llc -march=amdgcn -verify-machineinstrs -amdgpu-s-branch-bits=4 -o %t.o -filetype=obj %s
; RUN: llvm-readobj -r %t.o | FileCheck --check-prefix=OBJ %s
; OBJ: Relocations [
; OBJ-NEXT: ]
; Restrict maximum branch to between +7 and -8 dwords
; Used to emit an always 4 byte instruction. Inline asm always assumes
; each instruction is the maximum size.
declare void @llvm.amdgcn.s.sleep(i32) #0
declare i32 @llvm.amdgcn.workitem.id.x() #1
; GCN-LABEL: {{^}}uniform_conditional_max_short_forward_branch:
; GCN: s_load_dword [[CND:s[0-9]+]]
; GCN: s_cmp_eq_u32 [[CND]], 0
; GCN-NEXT: s_cbranch_scc1 [[BB3:BB[0-9]+_[0-9]+]]
; GCN-NEXT: ; %bb.1: ; %bb2
; GCN-NEXT: ;;#ASMSTART
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: ;;#ASMEND
; GCN-NEXT: s_sleep 0
; GCN-NEXT: [[BB3]]: ; %bb3
; GCN: v_mov_b32_e32 [[V_CND:v[0-9]+]], [[CND]]
; GCN: buffer_store_dword [[V_CND]]
; GCN: s_endpgm
define amdgpu_kernel void @uniform_conditional_max_short_forward_branch(i32 addrspace(1)* %arg, i32 %cnd) #0 {
bb:
%cmp = icmp eq i32 %cnd, 0
br i1 %cmp, label %bb3, label %bb2 ; +8 dword branch
bb2:
; 24 bytes
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
call void @llvm.amdgcn.s.sleep(i32 0)
br label %bb3
bb3:
store volatile i32 %cnd, i32 addrspace(1)* %arg
ret void
}
; GCN-LABEL: {{^}}uniform_conditional_min_long_forward_branch:
; GCN: s_load_dword [[CND:s[0-9]+]]
; GCN: s_cmp_eq_u32 [[CND]], 0
; GCN-NEXT: s_cbranch_scc0 [[LONGBB:BB[0-9]+_[0-9]+]]
; GCN-NEXT: [[LONG_JUMP:BB[0-9]+_[0-9]+]]: ; %bb0
; GCN-NEXT: s_getpc_b64 s{{\[}}[[PC_LO:[0-9]+]]:[[PC_HI:[0-9]+]]{{\]}}
; GCN-NEXT: s_add_u32 s[[PC_LO]], s[[PC_LO]], [[ENDBB:BB[0-9]+_[0-9]+]]-([[LONG_JUMP]]+4)
; GCN-NEXT: s_addc_u32 s[[PC_HI]], s[[PC_HI]], 0
; GCN-NEXT: s_setpc_b64 s{{\[}}[[PC_LO]]:[[PC_HI]]{{\]}}
; GCN-NEXT: [[LONGBB]]:
; GCN-NEXT: ;;#ASMSTART
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN-NEXT: ;;#ASMEND
; GCN-NEXT: [[ENDBB]]:
; GCN: v_mov_b32_e32 [[V_CND:v[0-9]+]], [[CND]]
; GCN: buffer_store_dword [[V_CND]]
; GCN: s_endpgm
define amdgpu_kernel void @uniform_conditional_min_long_forward_branch(i32 addrspace(1)* %arg, i32 %cnd) #0 {
bb0:
%cmp = icmp eq i32 %cnd, 0
br i1 %cmp, label %bb3, label %bb2 ; +9 dword branch
bb2:
; 32 bytes
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br label %bb3
bb3:
store volatile i32 %cnd, i32 addrspace(1)* %arg
ret void
}
; GCN-LABEL: {{^}}uniform_conditional_min_long_forward_vcnd_branch:
; GCN: s_load_dword [[CND:s[0-9]+]]
; GCN-DAG: v_mov_b32_e32 [[V_CND:v[0-9]+]], [[CND]]
; GCN-DAG: v_cmp_eq_f32_e64 [[UNMASKED:s\[[0-9]+:[0-9]+\]]], [[CND]], 0
; GCN-DAG: s_and_b64 vcc, exec, [[UNMASKED]]
; GCN: s_cbranch_vccz [[LONGBB:BB[0-9]+_[0-9]+]]
; GCN-NEXT: [[LONG_JUMP:BB[0-9]+_[0-9]+]]: ; %bb0
; GCN-NEXT: s_getpc_b64 s{{\[}}[[PC_LO:[0-9]+]]:[[PC_HI:[0-9]+]]{{\]}}
; GCN-NEXT: s_add_u32 s[[PC_LO]], s[[PC_LO]], [[ENDBB:BB[0-9]+_[0-9]+]]-([[LONG_JUMP]]+4)
; GCN-NEXT: s_addc_u32 s[[PC_HI]], s[[PC_HI]], 0
; GCN-NEXT: s_setpc_b64 s{{\[}}[[PC_LO]]:[[PC_HI]]{{\]}}
; GCN-NEXT: [[LONGBB]]:
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: [[ENDBB]]:
; GCN: buffer_store_dword [[V_CND]]
; GCN: s_endpgm
define amdgpu_kernel void @uniform_conditional_min_long_forward_vcnd_branch(float addrspace(1)* %arg, float %cnd) #0 {
bb0:
%cmp = fcmp oeq float %cnd, 0.0
br i1 %cmp, label %bb3, label %bb2 ; + 8 dword branch
bb2:
call void asm sideeffect " ; 32 bytes
v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br label %bb3
bb3:
store volatile float %cnd, float addrspace(1)* %arg
ret void
}
; GCN-LABEL: {{^}}min_long_forward_vbranch:
; GCN: buffer_load_dword
; GCN: v_cmp_ne_u32_e32 vcc, 0, v{{[0-9]+}}
; GCN: s_and_saveexec_b64 [[SAVE:s\[[0-9]+:[0-9]+\]]], vcc
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: s_or_b64 exec, exec, [[SAVE]]
; GCN: buffer_store_dword
; GCN: s_endpgm
define amdgpu_kernel void @min_long_forward_vbranch(i32 addrspace(1)* %arg) #0 {
bb:
%tid = call i32 @llvm.amdgcn.workitem.id.x()
%tid.ext = zext i32 %tid to i64
%gep = getelementptr inbounds i32, i32 addrspace(1)* %arg, i64 %tid.ext
%load = load volatile i32, i32 addrspace(1)* %gep
%cmp = icmp eq i32 %load, 0
br i1 %cmp, label %bb3, label %bb2 ; + 8 dword branch
bb2:
call void asm sideeffect " ; 32 bytes
v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br label %bb3
bb3:
store volatile i32 %load, i32 addrspace(1)* %gep
ret void
}
; GCN-LABEL: {{^}}long_backward_sbranch:
; GCN: s_mov_b32 [[LOOPIDX:s[0-9]+]], 0{{$}}
; GCN: [[LOOPBB:BB[0-9]+_[0-9]+]]: ; %bb2
; GCN-NEXT: ; =>This Inner Loop Header: Depth=1
; GCN-NEXT: s_add_i32 [[INC:s[0-9]+]], [[LOOPIDX]], 1
; GCN-NEXT: s_cmp_lt_i32 [[INC]], 10
; GCN-NEXT: ;;#ASMSTART
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: ;;#ASMEND
; GCN-NEXT: s_cbranch_scc0 [[ENDBB:BB[0-9]+_[0-9]+]]
; GCN-NEXT: [[LONG_JUMP:BB[0-9]+_[0-9]+]]: ; %bb2
; GCN-NEXT: ; in Loop: Header=[[LOOPBB]] Depth=1
; GCN-NEXT: s_getpc_b64 s{{\[}}[[PC_LO:[0-9]+]]:[[PC_HI:[0-9]+]]{{\]}}
; GCN-NEXT: s_sub_u32 s[[PC_LO]], s[[PC_LO]], ([[LONG_JUMP]]+4)-[[LOOPBB]]
; GCN-NEXT: s_subb_u32 s[[PC_HI]], s[[PC_HI]], 0
; GCN-NEXT: s_setpc_b64 s{{\[}}[[PC_LO]]:[[PC_HI]]{{\]}}
; GCN-NEXT: [[ENDBB]]:
; GCN-NEXT: s_endpgm
define amdgpu_kernel void @long_backward_sbranch(i32 addrspace(1)* %arg) #0 {
bb:
br label %bb2
bb2:
%loop.idx = phi i32 [ 0, %bb ], [ %inc, %bb2 ]
; 24 bytes
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
%inc = add nsw i32 %loop.idx, 1 ; add cost 4
%cmp = icmp slt i32 %inc, 10 ; condition cost = 8
br i1 %cmp, label %bb2, label %bb3 ; -
bb3:
ret void
}
; Requires expansion of unconditional branch from %bb2 to %bb4 (and
; expansion of conditional branch from %bb to %bb3.
; GCN-LABEL: {{^}}uniform_unconditional_min_long_forward_branch:
; GCN: s_cmp_eq_u32
; GCN-NEXT: s_cbranch_scc0 [[BB2:BB[0-9]+_[0-9]+]]
; GCN-NEXT: [[LONG_JUMP0:BB[0-9]+_[0-9]+]]: ; %bb0
; GCN-NEXT: s_getpc_b64 s{{\[}}[[PC0_LO:[0-9]+]]:[[PC0_HI:[0-9]+]]{{\]}}
; GCN-NEXT: s_add_u32 s[[PC0_LO]], s[[PC0_LO]], [[BB3:BB[0-9]_[0-9]+]]-([[LONG_JUMP0]]+4)
; GCN-NEXT: s_addc_u32 s[[PC0_HI]], s[[PC0_HI]], 0{{$}}
; GCN-NEXT: s_setpc_b64 s{{\[}}[[PC0_LO]]:[[PC0_HI]]{{\]}}
; GCN-NEXT: [[BB2]]: ; %bb2
; GCN: v_mov_b32_e32 [[BB2_K:v[0-9]+]], 17
; GCN: buffer_store_dword [[BB2_K]]
; GCN-NEXT: [[LONG_JUMP1:BB[0-9]+_[0-9]+]]: ; %bb2
; GCN-NEXT: s_getpc_b64 s{{\[}}[[PC1_LO:[0-9]+]]:[[PC1_HI:[0-9]+]]{{\]}}
; GCN-NEXT: s_add_u32 s[[PC1_LO]], s[[PC1_LO]], [[BB4:BB[0-9]_[0-9]+]]-([[LONG_JUMP1]]+4)
; GCN-NEXT: s_addc_u32 s[[PC1_HI]], s[[PC1_HI]], 0{{$}}
; GCN-NEXT: s_setpc_b64 s{{\[}}[[PC1_LO]]:[[PC1_HI]]{{\]}}
; GCN: [[BB3]]: ; %bb3
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: ;;#ASMEND
; GCN-NEXT: [[BB4]]: ; %bb4
; GCN: v_mov_b32_e32 [[BB4_K:v[0-9]+]], 63
; GCN: buffer_store_dword [[BB4_K]]
; GCN-NEXT: s_endpgm
; GCN-NEXT: .Lfunc_end{{[0-9]+}}:
define amdgpu_kernel void @uniform_unconditional_min_long_forward_branch(i32 addrspace(1)* %arg, i32 %arg1) {
bb0:
%tmp = icmp ne i32 %arg1, 0
br i1 %tmp, label %bb2, label %bb3
bb2:
store volatile i32 17, i32 addrspace(1)* undef
br label %bb4
bb3:
; 32 byte asm
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br label %bb4
bb4:
store volatile i32 63, i32 addrspace(1)* %arg
ret void
}
; GCN-LABEL: {{^}}uniform_unconditional_min_long_backward_branch:
; GCN-NEXT: ; %bb.0: ; %entry
; GCN-NEXT: [[LOOP:BB[0-9]_[0-9]+]]: ; %loop
; GCN-NEXT: ; =>This Inner Loop Header: Depth=1
; GCN-NEXT: ;;#ASMSTART
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: ;;#ASMEND
; GCN-NEXT: [[LONGBB:BB[0-9]+_[0-9]+]]: ; %loop
; GCN-NEXT: ; in Loop: Header=[[LOOP]] Depth=1
; GCN-NEXT: s_getpc_b64 s{{\[}}[[PC_LO:[0-9]+]]:[[PC_HI:[0-9]+]]{{\]}}
; GCN-NEXT: s_sub_u32 s[[PC_LO]], s[[PC_LO]], ([[LONGBB]]+4)-[[LOOP]]
; GCN-NEXT: s_subb_u32 s[[PC_HI]], s[[PC_HI]], 0{{$}}
; GCN-NEXT: s_setpc_b64 s{{\[}}[[PC_LO]]:[[PC_HI]]{{\]}}
; GCN-NEXT .Lfunc_end{{[0-9]+}}:
define amdgpu_kernel void @uniform_unconditional_min_long_backward_branch(i32 addrspace(1)* %arg, i32 %arg1) {
entry:
br label %loop
loop:
; 32 byte asm
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br label %loop
}
; Expansion of branch from %bb1 to %bb3 introduces need to expand
; branch from %bb0 to %bb2
; GCN-LABEL: {{^}}expand_requires_expand:
; GCN-NEXT: ; %bb.0: ; %bb0
; GCN: s_load_dword
; GCN: s_cmp_lt_i32 s{{[0-9]+}}, 0{{$}}
; GCN-NEXT: s_cbranch_scc0 [[BB1:BB[0-9]+_[0-9]+]]
; GCN-NEXT: [[LONGBB0:BB[0-9]+_[0-9]+]]: ; %bb0
; GCN-NEXT: s_getpc_b64 s{{\[}}[[PC0_LO:[0-9]+]]:[[PC0_HI:[0-9]+]]{{\]}}
; GCN-NEXT: s_add_u32 s[[PC0_LO]], s[[PC0_LO]], [[BB2:BB[0-9]_[0-9]+]]-([[LONGBB0]]+4)
; GCN-NEXT: s_addc_u32 s[[PC0_HI]], s[[PC0_HI]], 0{{$}}
; GCN-NEXT: s_setpc_b64 s{{\[}}[[PC0_LO]]:[[PC0_HI]]{{\]}}
; GCN-NEXT: [[BB1]]: ; %bb1
; GCN-NEXT: s_load_dword
; GCN-NEXT: s_waitcnt lgkmcnt(0)
; GCN-NEXT: s_cmp_eq_u32 s{{[0-9]+}}, 3{{$}}
; GCN-NEXT: s_cbranch_scc0 [[BB2:BB[0-9]_[0-9]+]]
; GCN-NEXT: [[LONGBB1:BB[0-9]+_[0-9]+]]: ; %bb1
; GCN-NEXT: s_getpc_b64 s{{\[}}[[PC1_LO:[0-9]+]]:[[PC1_HI:[0-9]+]]{{\]}}
; GCN-NEXT: s_add_u32 s[[PC1_LO]], s[[PC1_LO]], [[BB3:BB[0-9]+_[0-9]+]]-([[LONGBB1]]+4)
; GCN-NEXT: s_addc_u32 s[[PC1_HI]], s[[PC1_HI]], 0{{$}}
; GCN-NEXT: s_setpc_b64 s{{\[}}[[PC1_LO]]:[[PC1_HI]]{{\]}}
; GCN-NEXT: [[BB2]]: ; %bb2
; GCN-NEXT: ;;#ASMSTART
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: v_nop_e64
; GCN-NEXT: ;;#ASMEND
; GCN-NEXT: [[BB3]]: ; %bb3
; GCN-NEXT: ;;#ASMSTART
; GCN-NEXT: v_nop_e64
; GCN-NEXT: ;;#ASMEND
; GCN-NEXT: ;;#ASMSTART
; GCN-NEXT: v_nop_e64
; GCN-NEXT: ;;#ASMEND
; GCN-NEXT: s_endpgm
define amdgpu_kernel void @expand_requires_expand(i32 %cond0) #0 {
bb0:
%tmp = tail call i32 @llvm.amdgcn.workitem.id.x() #0
%cmp0 = icmp slt i32 %cond0, 0
br i1 %cmp0, label %bb2, label %bb1
bb1:
%val = load volatile i32, i32 addrspace(4)* undef
%cmp1 = icmp eq i32 %val, 3
br i1 %cmp1, label %bb3, label %bb2
bb2:
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br label %bb3
bb3:
; These NOPs prevent tail-duplication-based outlining
; from firing, which defeats the need to expand the branches and this test.
call void asm sideeffect
"v_nop_e64", ""() #0
call void asm sideeffect
"v_nop_e64", ""() #0
ret void
}
; Requires expanding of required skip branch.
; GCN-LABEL: {{^}}uniform_inside_divergent:
; GCN: v_cmp_gt_u32_e32 vcc, 16, v{{[0-9]+}}
; GCN-NEXT: s_and_saveexec_b64 [[MASK:s\[[0-9]+:[0-9]+\]]], vcc
; GCN-NEXT: ; mask branch [[ENDIF:BB[0-9]+_[0-9]+]]
; GCN-NEXT: s_cbranch_execnz [[IF:BB[0-9]+_[0-9]+]]
; GCN-NEXT: [[LONGBB:BB[0-9]+_[0-9]+]]: ; %entry
; GCN-NEXT: s_getpc_b64 s{{\[}}[[PC_LO:[0-9]+]]:[[PC_HI:[0-9]+]]{{\]}}
; GCN-NEXT: s_add_u32 s[[PC_LO]], s[[PC_LO]], [[BB2:BB[0-9]_[0-9]+]]-([[LONGBB]]+4)
; GCN-NEXT: s_addc_u32 s[[PC_HI]], s[[PC_HI]], 0{{$}}
; GCN-NEXT: s_setpc_b64 s{{\[}}[[PC_LO]]:[[PC_HI]]{{\]}}
; GCN-NEXT: [[IF]]: ; %if
; GCN: buffer_store_dword
; GCN: s_cmp_lg_u32
; GCN: s_cbranch_scc1 [[ENDIF]]
; GCN-NEXT: ; %bb.2: ; %if_uniform
; GCN: buffer_store_dword
; GCN-NEXT: [[ENDIF]]: ; %endif
; GCN-NEXT: s_or_b64 exec, exec, [[MASK]]
; GCN-NEXT: s_sleep 5
; GCN-NEXT: s_endpgm
define amdgpu_kernel void @uniform_inside_divergent(i32 addrspace(1)* %out, i32 %cond) #0 {
entry:
%tid = call i32 @llvm.amdgcn.workitem.id.x()
%d_cmp = icmp ult i32 %tid, 16
br i1 %d_cmp, label %if, label %endif
if:
store i32 0, i32 addrspace(1)* %out
%u_cmp = icmp eq i32 %cond, 0
br i1 %u_cmp, label %if_uniform, label %endif
if_uniform:
store i32 1, i32 addrspace(1)* %out
br label %endif
endif:
; layout can remove the split branch if it can copy the return block.
; This call makes the return block long enough that it doesn't get copied.
call void @llvm.amdgcn.s.sleep(i32 5);
ret void
}
; si_mask_branch
; GCN-LABEL: {{^}}analyze_mask_branch:
; GCN: v_cmp_nlt_f32_e32 vcc
; GCN-NEXT: s_and_saveexec_b64 [[TEMP_MASK:s\[[0-9]+:[0-9]+\]]], vcc
; GCN-NEXT: s_xor_b64 [[MASK:s\[[0-9]+:[0-9]+\]]], exec, [[TEMP_MASK]]
; GCN-NEXT: ; mask branch [[FLOW:BB[0-9]+_[0-9]+]]
; GCN: [[FLOW]]: ; %Flow
; GCN-NEXT: s_or_saveexec_b64 [[TEMP_MASK1:s\[[0-9]+:[0-9]+\]]], [[MASK]]
; GCN-NEXT: s_xor_b64 exec, exec, [[TEMP_MASK1]]
; GCN-NEXT: ; mask branch [[RET:BB[0-9]+_[0-9]+]]
; GCN: [[LOOP_BODY:BB[0-9]+_[0-9]+]]: ; %loop{{$}}
; GCN: ;;#ASMSTART
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: v_nop_e64
; GCN: ;;#ASMEND
; GCN: s_cbranch_vccz [[RET]]
Generalize MergeBlockIntoPredecessor. Replace uses of MergeBasicBlockIntoOnlyPred. Summary: Two utils methods have essentially the same functionality. This is an attempt to merge them into one. 1. lib/Transforms/Utils/Local.cpp : MergeBasicBlockIntoOnlyPred 2. lib/Transforms/Utils/BasicBlockUtils.cpp : MergeBlockIntoPredecessor Prior to the patch: 1. MergeBasicBlockIntoOnlyPred Updates either DomTree or DeferredDominance Moves all instructions from Pred to BB, deletes Pred Asserts BB has single predecessor If address was taken, replace the block address with constant 1 (?) 2. MergeBlockIntoPredecessor Updates DomTree, LoopInfo and MemoryDependenceResults Moves all instruction from BB to Pred, deletes BB Returns if doesn't have a single predecessor Returns if BB's address was taken After the patch: Method 2. MergeBlockIntoPredecessor is attempting to become the new default: Updates DomTree or DeferredDominance, and LoopInfo and MemoryDependenceResults Moves all instruction from BB to Pred, deletes BB Returns if doesn't have a single predecessor Returns if BB's address was taken Uses of MergeBasicBlockIntoOnlyPred that need to be replaced: 1. lib/Transforms/Scalar/LoopSimplifyCFG.cpp Updated in this patch. No challenges. 2. lib/CodeGen/CodeGenPrepare.cpp Updated in this patch. i. eliminateFallThrough is straightforward, but I added using a temporary array to avoid the iterator invalidation. ii. eliminateMostlyEmptyBlock(s) methods also now use a temporary array for blocks Some interesting aspects: - Since Pred is not deleted (BB is), the entry block does not need updating. - The entry block was being updated with the deleted block in eliminateMostlyEmptyBlock. Added assert to make obvious that BB=SinglePred. - isMergingEmptyBlockProfitable assumes BB is the one to be deleted. - eliminateMostlyEmptyBlock(BB) does not delete BB on one path, it deletes its unique predecessor instead. - adding some test owner as subscribers for the interesting tests modified: test/CodeGen/X86/avx-cmp.ll test/CodeGen/AMDGPU/nested-loop-conditions.ll test/CodeGen/AMDGPU/si-annotate-cf.ll test/CodeGen/X86/hoist-spill.ll test/CodeGen/X86/2006-11-17-IllegalMove.ll 3. lib/Transforms/Scalar/JumpThreading.cpp Not covered in this patch. It is the only use case using the DeferredDominance. I would defer to Brian Rzycki to make this replacement. Reviewers: chandlerc, spatel, davide, brzycki, bkramer, javed.absar Subscribers: qcolombet, sanjoy, nemanjai, nhaehnle, jlebar, tpr, kbarton, RKSimon, wmi, arsenm, llvm-commits Differential Revision: https://reviews.llvm.org/D48202 llvm-svn: 335183
2018-06-21 06:01:04 +08:00
; GCN-NEXT: [[LONGBB:BB[0-9]+_[0-9]+]]: ; %loop
; GCN-NEXT: ; in Loop: Header=[[LOOP_BODY]] Depth=1
; GCN-NEXT: s_getpc_b64 s{{\[}}[[PC_LO:[0-9]+]]:[[PC_HI:[0-9]+]]{{\]}}
; GCN-NEXT: s_sub_u32 s[[PC_LO]], s[[PC_LO]], ([[LONGBB]]+4)-[[LOOP_BODY]]
; GCN-NEXT: s_subb_u32 s[[PC_HI]], s[[PC_HI]], 0
; GCN-NEXT: s_setpc_b64 s{{\[}}[[PC_LO]]:[[PC_HI]]{{\]}}
; GCN-NEXT: [[RET]]: ; %UnifiedReturnBlock
; GCN-NEXT: s_endpgm
define amdgpu_kernel void @analyze_mask_branch() #0 {
entry:
%reg = call float asm sideeffect "v_mov_b32_e64 $0, 0", "=v"()
%cmp0 = fcmp ogt float %reg, 0.000000e+00
br i1 %cmp0, label %loop, label %ret
loop:
%phi = phi float [ 0.000000e+00, %loop_body ], [ 1.000000e+00, %entry ]
call void asm sideeffect
"v_nop_e64
v_nop_e64", ""() #0
%cmp1 = fcmp olt float %phi, 8.0
br i1 %cmp1, label %loop_body, label %ret
loop_body:
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br label %loop
ret:
store volatile i32 7, i32 addrspace(1)* undef
ret void
}
; GCN-LABEL: {{^}}long_branch_hang:
; GCN: s_cmp_lt_i32 s{{[0-9]+}}, 6
AMDGPU: Add pass to lower kernel arguments to loads This replaces most argument uses with loads, but for now not all. The code in SelectionDAG for calling convention lowering is actively harmful for amdgpu_kernel. It attempts to split the argument types into register legal types, which results in low quality code for arbitary types. Since all kernel arguments are passed in memory, we just want the raw types. I've tried a couple of methods of mitigating this in SelectionDAG, but it's easier to just bypass this problem alltogether. It's possible to hack around the problem in the initial lowering, but the real problem is the DAG then expects to be able to use CopyToReg/CopyFromReg for uses of the arguments outside the block. Exposing the argument loads in the IR also has the advantage that the LoadStoreVectorizer can merge them. I'm not sure the best approach to dealing with the IR argument list is. The patch as-is just leaves the IR arguments in place, so all the existing code will still compute the same kernarg size and pointlessly lowers the arguments. Arguably the frontend should emit kernels with an empty argument list in the first place. Alternatively a dummy array could be inserted as a single argument just to reserve space. This does have some disadvantages. Local pointer kernel arguments can no longer have AssertZext placed on them as the equivalent !range metadata is not valid on pointer typed loads. This is mostly bad for SI which needs to know about the known bits in order to use the DS instruction offset, so in this case this is not done. More importantly, this skips noalias arguments since this pass does not yet convert this to the equivalent !alias.scope and !noalias metadata. Producing this metadata correctly seems to be tricky, although this logically is the same as inlining into a function which doesn't exist. Additionally, exposing these loads to the vectorizer may result in degraded aliasing information if a pointer load is merged with another argument load. I'm also not entirely sure this is preserving the current clover ABI, although I would greatly prefer if it would stop widening arguments and match the HSA ABI. As-is I think it is extending < 4-byte arguments to 4-bytes but doesn't align them to 4-bytes. llvm-svn: 335650
2018-06-27 03:10:00 +08:00
; GCN: s_cbranch_scc1 {{BB[0-9]+_[0-9]+}}
Codegen: Make chains from trellis-shaped CFGs Lay out trellis-shaped CFGs optimally. A trellis of the shape below: A B |\ /| | \ / | | X | | / \ | |/ \| C D would be laid out A; B->C ; D by the current layout algorithm. Now we identify trellises and lay them out either A->C; B->D or A->D; B->C. This scales with an increasing number of predecessors. A trellis is a a group of 2 or more predecessor blocks that all have the same successors. because of this we can tail duplicate to extend existing trellises. As an example consider the following CFG: B D F H / \ / \ / \ / \ A---C---E---G---Ret Where A,C,E,G are all small (Currently 2 instructions). The CFG preserving layout is then A,B,C,D,E,F,G,H,Ret. The current code will copy C into B, E into D and G into F and yield the layout A,C,B(C),E,D(E),F(G),G,H,ret define void @straight_test(i32 %tag) { entry: br label %test1 test1: ; A %tagbit1 = and i32 %tag, 1 %tagbit1eq0 = icmp eq i32 %tagbit1, 0 br i1 %tagbit1eq0, label %test2, label %optional1 optional1: ; B call void @a() br label %test2 test2: ; C %tagbit2 = and i32 %tag, 2 %tagbit2eq0 = icmp eq i32 %tagbit2, 0 br i1 %tagbit2eq0, label %test3, label %optional2 optional2: ; D call void @b() br label %test3 test3: ; E %tagbit3 = and i32 %tag, 4 %tagbit3eq0 = icmp eq i32 %tagbit3, 0 br i1 %tagbit3eq0, label %test4, label %optional3 optional3: ; F call void @c() br label %test4 test4: ; G %tagbit4 = and i32 %tag, 8 %tagbit4eq0 = icmp eq i32 %tagbit4, 0 br i1 %tagbit4eq0, label %exit, label %optional4 optional4: ; H call void @d() br label %exit exit: ret void } here is the layout after D27742: straight_test: # @straight_test ; ... Prologue elided ; BB#0: # %entry ; A (merged with test1) ; ... More prologue elided mr 30, 3 andi. 3, 30, 1 bc 12, 1, .LBB0_2 ; BB#1: # %test2 ; C rlwinm. 3, 30, 0, 30, 30 beq 0, .LBB0_3 b .LBB0_4 .LBB0_2: # %optional1 ; B (copy of C) bl a nop rlwinm. 3, 30, 0, 30, 30 bne 0, .LBB0_4 .LBB0_3: # %test3 ; E rlwinm. 3, 30, 0, 29, 29 beq 0, .LBB0_5 b .LBB0_6 .LBB0_4: # %optional2 ; D (copy of E) bl b nop rlwinm. 3, 30, 0, 29, 29 bne 0, .LBB0_6 .LBB0_5: # %test4 ; G rlwinm. 3, 30, 0, 28, 28 beq 0, .LBB0_8 b .LBB0_7 .LBB0_6: # %optional3 ; F (copy of G) bl c nop rlwinm. 3, 30, 0, 28, 28 beq 0, .LBB0_8 .LBB0_7: # %optional4 ; H bl d nop .LBB0_8: # %exit ; Ret ld 30, 96(1) # 8-byte Folded Reload addi 1, 1, 112 ld 0, 16(1) mtlr 0 blr The tail-duplication has produced some benefit, but it has also produced a trellis which is not laid out optimally. With this patch, we improve the layouts of such trellises, and decrease the cost calculation for tail-duplication accordingly. This patch produces the layout A,C,E,G,B,D,F,H,Ret. This layout does have back edges, which is a negative, but it has a bigger compensating positive, which is that it handles the case where there are long strings of skipped blocks much better than the original layout. Both layouts handle runs of executed blocks equally well. Branch prediction also improves if there is any correlation between subsequent optional blocks. Here is the resulting concrete layout: straight_test: # @straight_test ; BB#0: # %entry ; A (merged with test1) mr 30, 3 andi. 3, 30, 1 bc 12, 1, .LBB0_4 ; BB#1: # %test2 ; C rlwinm. 3, 30, 0, 30, 30 bne 0, .LBB0_5 .LBB0_2: # %test3 ; E rlwinm. 3, 30, 0, 29, 29 bne 0, .LBB0_6 .LBB0_3: # %test4 ; G rlwinm. 3, 30, 0, 28, 28 bne 0, .LBB0_7 b .LBB0_8 .LBB0_4: # %optional1 ; B (Copy of C) bl a nop rlwinm. 3, 30, 0, 30, 30 beq 0, .LBB0_2 .LBB0_5: # %optional2 ; D (Copy of E) bl b nop rlwinm. 3, 30, 0, 29, 29 beq 0, .LBB0_3 .LBB0_6: # %optional3 ; F (Copy of G) bl c nop rlwinm. 3, 30, 0, 28, 28 beq 0, .LBB0_8 .LBB0_7: # %optional4 ; H bl d nop .LBB0_8: # %exit Differential Revision: https://reviews.llvm.org/D28522 llvm-svn: 295223
2017-02-16 03:49:14 +08:00
; GCN-NEXT: s_branch [[LONG_BR_0:BB[0-9]+_[0-9]+]]
; GCN-NEXT: BB{{[0-9]+_[0-9]+}}:
; GCN: s_add_u32 s{{[0-9]+}}, s{{[0-9]+}}, [[LONG_BR_DEST0:BB[0-9]+_[0-9]+]]-(
; GCN-NEXT: s_addc_u32
; GCN-NEXT: s_setpc_b64
; GCN-NEXT: [[LONG_BR_0]]:
; GCN-DAG: v_cmp_lt_i32
; GCN-DAG: v_cmp_gt_i32
; GCN: s_cbranch_vccnz
; GCN: s_setpc_b64
; GCN: s_setpc_b64
; GCN: [[LONG_BR_DEST0]]
; GCN: s_cbranch_vccz
; GCN: s_setpc_b64
; GCN: s_endpgm
define amdgpu_kernel void @long_branch_hang(i32 addrspace(1)* nocapture %arg, i32 %arg1, i32 %arg2, i32 %arg3, i32 %arg4, i64 %arg5) #0 {
bb:
%tmp = icmp slt i32 %arg2, 9
%tmp6 = icmp eq i32 %arg1, 0
%tmp7 = icmp sgt i32 %arg4, 0
%tmp8 = icmp sgt i32 %arg4, 5
br i1 %tmp8, label %bb9, label %bb13
bb9: ; preds = %bb
%tmp10 = and i1 %tmp7, %tmp
%tmp11 = icmp slt i32 %arg3, %arg4
%tmp12 = or i1 %tmp11, %tmp7
br i1 %tmp12, label %bb19, label %bb14
bb13: ; preds = %bb
call void asm sideeffect
"v_nop_e64
v_nop_e64
v_nop_e64
v_nop_e64", ""() #0
br i1 %tmp6, label %bb19, label %bb14
bb14: ; preds = %bb13, %bb9
%tmp15 = icmp slt i32 %arg3, %arg4
%tmp16 = or i1 %tmp15, %tmp
%tmp17 = and i1 %tmp6, %tmp16
%tmp18 = zext i1 %tmp17 to i32
br label %bb19
bb19: ; preds = %bb14, %bb13, %bb9
%tmp20 = phi i32 [ undef, %bb9 ], [ undef, %bb13 ], [ %tmp18, %bb14 ]
%tmp21 = getelementptr inbounds i32, i32 addrspace(1)* %arg, i64 %arg5
store i32 %tmp20, i32 addrspace(1)* %tmp21, align 4
ret void
}
attributes #0 = { nounwind }
attributes #1 = { nounwind readnone }