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llvm-mirror/test/CodeGen/AMDGPU/mul_int24.ll
Matt Arsenault 2b0231f519 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
2018-06-26 19:10:00 +00:00

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; RUN: llc -march=amdgcn -verify-machineinstrs < %s | FileCheck -check-prefix=GCN -check-prefix=SI -check-prefix=FUNC %s
; RUN: llc -march=amdgcn -mcpu=tonga -mattr=-flat-for-global -verify-machineinstrs < %s | FileCheck -check-prefix=GCN -check-prefix=VI -check-prefix=FUNC %s
; RUN: llc -march=r600 -mcpu=redwood < %s | FileCheck -check-prefix=EG -check-prefix=FUNC %s
; RUN: llc -march=r600 -mcpu=cayman < %s | FileCheck -check-prefix=CM -check-prefix=FUNC %s
; FUNC-LABEL: {{^}}test_smul24_i32:
; GCN-NOT: bfe
; GCN: v_mul_i32_i24
; Signed 24-bit multiply is not supported on pre-Cayman GPUs.
; EG: MULLO_INT
; Make sure we are not masking the inputs
; CM-NOT: AND
; CM: MUL_INT24
define amdgpu_kernel void @test_smul24_i32(i32 addrspace(1)* %out, i32 %a, i32 %b) #0 {
entry:
%a.shl = shl i32 %a, 8
%a.24 = ashr i32 %a.shl, 8
%b.shl = shl i32 %b, 8
%b.24 = ashr i32 %b.shl, 8
%mul24 = mul i32 %a.24, %b.24
store i32 %mul24, i32 addrspace(1)* %out
ret void
}
; FUNC-LABEL: {{^}}test_smulhi24_i64:
; GCN-NOT: bfe
; GCN-NOT: ashr
; GCN: v_mul_hi_i32_i24_e32 [[RESULT:v[0-9]+]],
; GCN-NEXT: buffer_store_dword [[RESULT]]
; EG: ASHR
; EG: ASHR
; EG: MULHI_INT
; CM-NOT: ASHR
; CM: MULHI_INT24
; CM: MULHI_INT24
; CM: MULHI_INT24
; CM: MULHI_INT24
define amdgpu_kernel void @test_smulhi24_i64(i32 addrspace(1)* %out, i32 %a, i32 %b) #0 {
entry:
%a.shl = shl i32 %a, 8
%a.24 = ashr i32 %a.shl, 8
%b.shl = shl i32 %b, 8
%b.24 = ashr i32 %b.shl, 8
%a.24.i64 = sext i32 %a.24 to i64
%b.24.i64 = sext i32 %b.24 to i64
%mul48 = mul i64 %a.24.i64, %b.24.i64
%mul48.hi = lshr i64 %mul48, 32
%mul24hi = trunc i64 %mul48.hi to i32
store i32 %mul24hi, i32 addrspace(1)* %out
ret void
}
; This requires handling of the original 64-bit mul node to eliminate
; unnecessary extension instructions because after legalization they
; will not be removed by SimplifyDemandedBits because there are
; multiple uses by the separate mul and mulhi.
; FUNC-LABEL: {{^}}test_smul24_i64:
; GCN: s_load_dword s
; GCN: s_load_dword s
; GCN-NOT: bfe
; GCN-NOT: ashr
; GCN-DAG: v_mul_hi_i32_i24_e32
; GCN-DAG: v_mul_i32_i24_e32
; GCN: buffer_store_dwordx2
define amdgpu_kernel void @test_smul24_i64(i64 addrspace(1)* %out, [8 x i32], i32 %a, [8 x i32], i32 %b) #0 {
%shl.i = shl i32 %a, 8
%shr.i = ashr i32 %shl.i, 8
%conv.i = sext i32 %shr.i to i64
%shl1.i = shl i32 %b, 8
%shr2.i = ashr i32 %shl1.i, 8
%conv3.i = sext i32 %shr2.i to i64
%mul.i = mul i64 %conv3.i, %conv.i
store i64 %mul.i, i64 addrspace(1)* %out
ret void
}
; FUNC-LABEL: {{^}}test_smul24_i64_square:
; GCN: s_load_dword [[A:s[0-9]+]]
; GCN-DAG: v_mul_hi_i32_i24_e64 v{{[0-9]+}}, [[A]], [[A]]
; GCN-DAG: v_mul_i32_i24_e64 v{{[0-9]+}}, [[A]], [[A]]
; GCN: buffer_store_dwordx2
define amdgpu_kernel void @test_smul24_i64_square(i64 addrspace(1)* %out, i32 %a, i32 %b) #0 {
%shl.i = shl i32 %a, 8
%shr.i = ashr i32 %shl.i, 8
%conv.i = sext i32 %shr.i to i64
%mul.i = mul i64 %conv.i, %conv.i
store i64 %mul.i, i64 addrspace(1)* %out
ret void
}
; FUNC-LABEL: {{^}}test_smul24_i33:
; GCN: s_load_dword s
; GCN: s_load_dword s
; GCN-NOT: and
; GCN-NOT: lshr
; GCN-DAG: v_mul_i32_i24_e32
; GCN-DAG: v_mul_hi_i32_i24_e32
; SI: v_lshl_b64 v{{\[[0-9]+:[0-9]+\]}}, v{{\[[0-9]+:[0-9]+\]}}, 31
; SI: v_ashr_i64 v{{\[[0-9]+:[0-9]+\]}}, v{{\[[0-9]+:[0-9]+\]}}, 31
; VI: v_lshlrev_b64 v{{\[[0-9]+:[0-9]+\]}}, 31, v{{\[[0-9]+:[0-9]+\]}}
; VI: v_ashrrev_i64 v{{\[[0-9]+:[0-9]+\]}}, 31, v{{\[[0-9]+:[0-9]+\]}}
; GCN: buffer_store_dwordx2
define amdgpu_kernel void @test_smul24_i33(i64 addrspace(1)* %out, i33 %a, i33 %b) #0 {
entry:
%a.shl = shl i33 %a, 9
%a.24 = ashr i33 %a.shl, 9
%b.shl = shl i33 %b, 9
%b.24 = ashr i33 %b.shl, 9
%mul24 = mul i33 %a.24, %b.24
%ext = sext i33 %mul24 to i64
store i64 %ext, i64 addrspace(1)* %out
ret void
}
; FUNC-LABEL: {{^}}test_smulhi24_i33:
; SI: s_load_dword s
; SI: s_load_dword s
; SI-NOT: bfe
; SI: v_mul_hi_i32_i24_e32 v[[MUL_HI:[0-9]+]],
; SI-NEXT: v_and_b32_e32 v[[HI:[0-9]+]], 1, v[[MUL_HI]]
; SI-NEXT: buffer_store_dword v[[HI]]
define amdgpu_kernel void @test_smulhi24_i33(i32 addrspace(1)* %out, i33 %a, i33 %b) {
entry:
%tmp0 = shl i33 %a, 9
%a_24 = ashr i33 %tmp0, 9
%tmp1 = shl i33 %b, 9
%b_24 = ashr i33 %tmp1, 9
%tmp2 = mul i33 %a_24, %b_24
%hi = lshr i33 %tmp2, 32
%trunc = trunc i33 %hi to i32
store i32 %trunc, i32 addrspace(1)* %out
ret void
}
; GCN-LABEL: {{^}}simplify_i24_crash:
; GCN: v_mul_i32_i24_e32 v[[VAL_LO:[0-9]+]]
; GCN: v_mov_b32_e32 v[[VAL_HI:[0-9]+]], v[[VAL_LO]]
; GCN: buffer_store_dwordx2 v{{\[}}[[VAL_LO]]:[[VAL_HI]]{{\]}}
define amdgpu_kernel void @simplify_i24_crash(<2 x i32> addrspace(1)* %out, i32 %arg0, <2 x i32> %arg1, <2 x i32> %arg2) {
bb:
%cmp = icmp eq i32 %arg0, 0
br i1 %cmp, label %bb11, label %bb7
bb11:
%tmp14 = shufflevector <2 x i32> %arg1, <2 x i32> undef, <2 x i32> zeroinitializer
%tmp16 = shufflevector <2 x i32> %arg2, <2 x i32> undef, <2 x i32> zeroinitializer
%tmp17 = shl <2 x i32> %tmp14, <i32 8, i32 8>
%tmp18 = ashr <2 x i32> %tmp17, <i32 8, i32 8>
%tmp19 = shl <2 x i32> %tmp16, <i32 8, i32 8>
%tmp20 = ashr <2 x i32> %tmp19, <i32 8, i32 8>
%tmp21 = mul <2 x i32> %tmp18, %tmp20
store <2 x i32> %tmp21, <2 x i32> addrspace(1)* %out
br label %bb7
bb7:
ret void
}
attributes #0 = { nounwind }
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