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AMDGPU: Other sizes of popcnt are fast

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We can chain bcnt instructions together, so
any width popcnt is pretty fast.

llvm-svn: 269950
This commit is contained in:
Matt Arsenault 2016-05-18 16:10:19 +00:00
parent 5b89989aa5
commit 41311e20a0
3 changed files with 77 additions and 2 deletions
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2
lib/Target/AMDGPU/AMDGPUTargetTransformInfo.h
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@ -76,7 +76,7 @@ public:
TTI::PopcntSupportKind getPopcntSupport(unsigned TyWidth) {
assert(isPowerOf2_32(TyWidth) && "Ty width must be power of 2");
return ST->hasBCNT(TyWidth) ? TTI::PSK_FastHardware : TTI::PSK_Software;
return TTI::PSK_FastHardware;
}
unsigned getNumberOfRegisters(bool Vector);

52
test/CodeGen/AMDGPU/ctpop64.ll
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@ -7,6 +7,9 @@ declare <4 x i64> @llvm.ctpop.v4i64(<4 x i64>) nounwind readnone
declare <8 x i64> @llvm.ctpop.v8i64(<8 x i64>) nounwind readnone
declare <16 x i64> @llvm.ctpop.v16i64(<16 x i64>) nounwind readnone
declare i65 @llvm.ctpop.i65(i65) nounwind readnone
declare i128 @llvm.ctpop.i128(i128) nounwind readnone
; FUNC-LABEL: {{^}}s_ctpop_i64:
; SI: s_load_dwordx2 [[SVAL:s\[[0-9]+:[0-9]+\]]], s{{\[[0-9]+:[0-9]+\]}}, 0xb
; VI: s_load_dwordx2 [[SVAL:s\[[0-9]+:[0-9]+\]]], s{{\[[0-9]+:[0-9]+\]}}, 0x2c
@ -141,3 +144,52 @@ endif:
store i64 %tmp5, i64 addrspace(1)* %out
ret void
}
; FUNC-LABEL: {{^}}s_ctpop_i128:
; GCN: s_bcnt1_i32_b64 [[SRESULT0:s[0-9]+]],
; GCN: s_bcnt1_i32_b64 [[SRESULT1:s[0-9]+]],
; GCN: s_add_i32 s{{[0-9]+}}, [[SRESULT0]], [[SRESULT1]]
; GCN: s_endpgm
define void @s_ctpop_i128(i32 addrspace(1)* noalias %out, i128 %val) nounwind {
%ctpop = call i128 @llvm.ctpop.i128(i128 %val) nounwind readnone
%truncctpop = trunc i128 %ctpop to i32
store i32 %truncctpop, i32 addrspace(1)* %out, align 4
ret void
}
; FUNC-LABEL: {{^}}s_ctpop_i65:
; GCN: s_bcnt1_i32_b64
; GCN: s_and_b32
; GCN: s_bcnt1_i32_b64
; GCN: s_add_i32
; GCN: s_endpgm
define void @s_ctpop_i65(i32 addrspace(1)* noalias %out, i65 %val) nounwind {
%ctpop = call i65 @llvm.ctpop.i65(i65 %val) nounwind readnone
%truncctpop = trunc i65 %ctpop to i32
store i32 %truncctpop, i32 addrspace(1)* %out, align 4
ret void
}
; FIXME: Should not have extra add
; FUNC-LABEL: {{^}}v_ctpop_i128:
; GCN-DAG: buffer_load_dwordx2 v{{\[}}[[VAL0:[0-9]+]]:[[VAL1:[0-9]+]]{{\]}}, off, s{{\[[0-9]+:[0-9]+\]}}, 0{{$}}
; GCN-DAG: buffer_load_dwordx2 v{{\[}}[[VAL2:[0-9]+]]:[[VAL3:[0-9]+]]{{\]}}, off, s{{\[[0-9]+:[0-9]+\]}}, 0 offset:8{{$}}
; GCN: v_bcnt_u32_b32_e64 [[MIDRESULT0:v[0-9]+]], v[[VAL2]], 0
; GCN: v_bcnt_u32_b32{{_e32|_e64}} [[MIDRESULT1:v[0-9]+]], v[[VAL3]], [[MIDRESULT0]]
; GCN: v_bcnt_u32_b32_e64 [[MIDRESULT2:v[0-9]+]], v[[VAL0]], 0
; GCN: v_bcnt_u32_b32{{_e32|_e64}} [[MIDRESULT3:v[0-9]+]], v[[VAL1]], [[MIDRESULT2]]
; GCN: v_add_i32_e32 [[RESULT:v[0-9]+]], vcc, [[MIDRESULT2]], [[MIDRESULT1]]
; GCN: buffer_store_dword [[RESULT]],
; GCN: s_endpgm
define void @v_ctpop_i128(i32 addrspace(1)* noalias %out, i128 addrspace(1)* noalias %in) nounwind {
%val = load i128, i128 addrspace(1)* %in, align 8
%ctpop = call i128 @llvm.ctpop.i128(i128 %val) nounwind readnone
%truncctpop = trunc i128 %ctpop to i32
store i32 %truncctpop, i32 addrspace(1)* %out, align 4
ret void
}

25
test/Transforms/LoopIdiom/AMDGPU/popcnt.ll
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@ -1,4 +1,4 @@
; RUN: opt -loop-idiom -mtriple=r600-- -mcpu=SI -S < %s | FileCheck %s
; RUN: opt -loop-idiom -mtriple=amdgcn-- -S < %s | FileCheck %s
; Mostly copied from x86 version.
@ -59,6 +59,29 @@ while.end: ; preds = %while.body, %entry
ret i32 %c.0.lcssa
}
; CHECK-LABEL: @popcount_i128
; CHECK: entry
; CHECK: llvm.ctpop.i128
; CHECK: ret
define i32 @popcount_i128(i128 %a) nounwind uwtable readnone ssp {
entry:
%tobool3 = icmp eq i128 %a, 0
br i1 %tobool3, label %while.end, label %while.body
while.body: ; preds = %entry, %while.body
%c.05 = phi i32 [ %inc, %while.body ], [ 0, %entry ]
%a.addr.04 = phi i128 [ %and, %while.body ], [ %a, %entry ]
%inc = add nsw i32 %c.05, 1
%sub = add i128 %a.addr.04, -1
%and = and i128 %sub, %a.addr.04
%tobool = icmp eq i128 %and, 0
br i1 %tobool, label %while.end, label %while.body
while.end: ; preds = %while.body, %entry
%c.0.lcssa = phi i32 [ 0, %entry ], [ %inc, %while.body ]
ret i32 %c.0.lcssa
}
; To recognize this pattern:
;int popcount(unsigned long long a, int mydata1, int mydata2) {
; int c = 0;