intel/fs: Allow copy propagation between MOVs of mixed sizes

This eliminates some spurious, size-converting moves.  For example, on
Ice Lake this helps dEQP-VK.spirv_assembly.type.vec3.i8.bitwise_xor_frag:

SIMD8 shader: 52 instructions. 1 loops. 4164 cycles. 0:0 spills:fills, 5 sends
SIMD8 shader: 49 instructions. 1 loops. 4044 cycles. 0:0 spills:fills, 5 sends

Unfortunately, this doesn't clean everything up.  Here's a subset of the
"before" assembly:

send(8)         g11<1>UW        g2<0,1,0>UD     0x02106e02
                            dp data 1 MsgDesc: ( untyped surface read, Surface = 2, SIMD8, Mask = 0xe) mlen 1 rlen 1 { align1 1Q };
mov(8)          g7<4>UB         g11<8,8,1>UD                    { align1 1Q };
mov(8)          g12<1>UB        g7<32,8,4>UB                    { align1 1Q };
send(8)         g13<1>UW        g2<0,1,0>UD     0x02106e03
                            dp data 1 MsgDesc: ( untyped surface read, Surface = 3, SIMD8, Mask = 0xe) mlen 1 rlen 1 { align1 1Q };
mov(8)          g15<1>UW        g12<8,8,1>UB                    { align1 1Q };
mov(8)          g8<4>UB         g13<8,8,1>UD                    { align1 1Q };
mov(8)          g14<1>UB        g8<32,8,4>UB                    { align1 1Q };
mov(8)          g16<1>UW        g14<8,8,1>UB                    { align1 1Q };
xor(8)          g17<1>UW        g15<8,8,1>UW    g16<8,8,1>UW    { align1 1Q };

And here's the same subset of the "after" assembly:

send(8)         g11<1>UW        g2<0,1,0>UD     0x02106e02
                            dp data 1 MsgDesc: ( untyped surface read, Surface = 2, SIMD8, Mask = 0xe) mlen 1 rlen 1 { align1 1Q };
mov(8)          g7<4>UB         g11<8,8,1>UD                    { align1 1Q };
send(8)         g13<1>UW        g2<0,1,0>UD     0x02106e03
                            dp data 1 MsgDesc: ( untyped surface read, Surface = 3, SIMD8, Mask = 0xe) mlen 1 rlen 1 { align1 1Q };
mov(8)          g15<1>UW        g7<32,8,4>UB                    { align1 1Q };
mov(8)          g8<4>UB         g13<8,8,1>UD                    { align1 1Q };
mov(8)          g16<1>UW        g8<32,8,4>UB                    { align1 1Q };
xor(8)          g17<1>UW        g15<8,8,1>UW    g16<8,8,1>UW    { align1 1Q };

There are a lot of regioning and type restrictions in
fs_visitor::try_copy_propagate, and I'm a little nervious about messing
with them too much.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Suggested-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9025>
This commit is contained in:
Ian Romanick
2021-04-13 14:07:19 -07:00
committed by Marge Bot
parent a147717a93
commit e3f502e007

View File

@@ -52,6 +52,7 @@ struct acp_entry : public exec_node {
unsigned size_read;
enum opcode opcode;
bool saturate;
bool is_partial_write;
};
struct block_data {
@@ -586,8 +587,11 @@ fs_visitor::try_copy_propagate(fs_inst *inst, int arg, acp_entry *entry)
* destination of the copy, and simply replacing the sources would give a
* program with different semantics.
*/
if (type_sz(entry->dst.type) < type_sz(inst->src[arg].type))
if ((type_sz(entry->dst.type) < type_sz(inst->src[arg].type) ||
entry->is_partial_write) &&
inst->opcode != BRW_OPCODE_MOV) {
return false;
}
/* Bail if the result of composing both strides cannot be expressed
* as another stride. This avoids, for example, trying to transform
@@ -680,7 +684,8 @@ fs_visitor::try_copy_propagate(fs_inst *inst, int arg, acp_entry *entry)
/* Compute the first component of the copy that the instruction is
* reading, and the base byte offset within that component.
*/
assert(entry->dst.offset % REG_SIZE == 0 && entry->dst.stride == 1);
assert((entry->dst.offset % REG_SIZE == 0 || inst->opcode == BRW_OPCODE_MOV) &&
entry->dst.stride == 1);
const unsigned component = rel_offset / type_sz(entry->dst.type);
const unsigned suboffset = rel_offset % type_sz(entry->dst.type);
@@ -950,7 +955,9 @@ can_propagate_from(fs_inst *inst)
(inst->src[0].file == FIXED_GRF &&
inst->src[0].is_contiguous())) &&
inst->src[0].type == inst->dst.type &&
!inst->is_partial_write()) ||
/* Subset of !is_partial_write() conditions. */
!((inst->predicate && inst->opcode != BRW_OPCODE_SEL) ||
!inst->dst.is_contiguous())) ||
is_identity_payload(FIXED_GRF, inst);
}
@@ -1012,6 +1019,7 @@ fs_visitor::opt_copy_propagation_local(void *copy_prop_ctx, bblock_t *block,
entry->size_read += inst->size_read(i);
entry->opcode = inst->opcode;
entry->saturate = inst->saturate;
entry->is_partial_write = inst->is_partial_write();
acp[entry->dst.nr % ACP_HASH_SIZE].push_tail(entry);
} else if (inst->opcode == SHADER_OPCODE_LOAD_PAYLOAD &&
inst->dst.file == VGRF) {