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nir/nir_lower_io: Optimize 32-bit inbounds access 

Perform address calculation in 32 bits when
dealing with inbounds array derefs.

Closes: #6562
Signed-off-by: Konstantin Seurer <konstantin.seurer@gmail.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16729>
This commit is contained in:
Konstantin Seurer 2022-05-26 21:15:11 +02:00 committed by Marge Bot
parent f19cbe98e3
commit 08577bbb70
1 changed files with 18 additions and 10 deletions
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28
src/compiler/nir/nir_lower_io.c
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@ -1820,22 +1820,30 @@ nir_explicit_io_address_from_deref(nir_builder *b, nir_deref_instr *deref,
case nir_deref_type_var:
return build_addr_for_var(b, deref->var, addr_format);
case nir_deref_type_ptr_as_array:
case nir_deref_type_array: {
unsigned stride = nir_deref_instr_array_stride(deref);
assert(stride > 0);
unsigned offset_bit_size = addr_get_offset_bit_size(base_addr, addr_format);
nir_ssa_def *index = nir_ssa_for_src(b, deref->arr.index, 1);
index = nir_i2i(b, index, addr_get_offset_bit_size(base_addr, addr_format));
return build_addr_iadd(b, base_addr, addr_format, deref->modes,
nir_amul_imm(b, index, stride));
}
nir_ssa_def *offset;
case nir_deref_type_ptr_as_array: {
nir_ssa_def *index = nir_ssa_for_src(b, deref->arr.index, 1);
index = nir_i2i(b, index, addr_get_offset_bit_size(base_addr, addr_format));
unsigned stride = nir_deref_instr_array_stride(deref);
return build_addr_iadd(b, base_addr, addr_format, deref->modes,
nir_amul_imm(b, index, stride));
/* If the access chain has been declared in-bounds, then we know it doesn't
* overflow the type. For nir_deref_type_array, this implies it cannot be
* negative. Also, since types in NIR have a maximum 32-bit size, we know the
* final result will fit in a 32-bit value so we can convert the index to
* 32-bit before multiplying and save ourselves from a 64-bit multiply.
*/
if (deref->arr.in_bounds && deref->deref_type == nir_deref_type_array) {
index = nir_u2u32(b, index);
offset = nir_u2u(b, nir_amul_imm(b, index, stride), offset_bit_size);
} else {
index = nir_i2i(b, index, offset_bit_size);
offset = nir_amul_imm(b, index, stride);
}
return build_addr_iadd(b, base_addr, addr_format, deref->modes, offset);
}
case nir_deref_type_array_wildcard: