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i965/compaction: Simplify jump target code.

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My attempts to clarify the code with _compacted/_uncompacted prefixed
variables apparently failed. Hopefully this is clearer.

In any case, the previous code wasn't clear enough to gcc to let it
optimize division by a power of two into a shift. No problems now.

Also, the previous code (in the ADD case) didn't work on 32-bit x86, due
to complicated set of interactions best summed up as unsigned division
and compiler optimizations.

Tested-by: Mark Janes <mark.a.janes@intel.com>
This commit is contained in:
Matt Turner 2014-09-27 09:39:49 -07:00
parent dce96f6da2
commit a36631b74c
1 changed files with 18 additions and 26 deletions
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44
src/mesa/drivers/dri/i965/brw_eu_compact.c
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@ -1201,28 +1201,24 @@ update_uip_jip(struct brw_context *brw, brw_inst *insn,
* - bytes on Gen8+; and
* - compacted instructions on Gen6+.
*/
int32_t jip = brw_inst_jip(brw, insn);
int32_t jip_compacted = jip / (brw->gen >= 8 ? sizeof(brw_compact_inst) : 1);
int32_t jip_uncompacted = jip / (brw->gen >= 8 ? sizeof(brw_inst) : 2);
int shift = brw->gen >= 8 ? 3 : 0;
int32_t jip_compacted = brw_inst_jip(brw, insn) >> shift;
jip_compacted -= compacted_between(this_old_ip,
this_old_ip + jip_uncompacted,
this_old_ip + (jip_compacted / 2),
compacted_counts);
brw_inst_set_jip(brw, insn,
jip_compacted * (brw->gen >= 8 ? sizeof(brw_compact_inst) : 1));
brw_inst_set_jip(brw, insn, jip_compacted << shift);
if (brw_inst_opcode(brw, insn) == BRW_OPCODE_ENDIF ||
brw_inst_opcode(brw, insn) == BRW_OPCODE_WHILE ||
(brw_inst_opcode(brw, insn) == BRW_OPCODE_ELSE && brw->gen <= 7))
return;
int32_t uip = brw_inst_uip(brw, insn);
int32_t uip_compacted = uip / (brw->gen >= 8 ? sizeof(brw_compact_inst) : 1);
int32_t uip_uncompacted = uip / (brw->gen >= 8 ? sizeof(brw_inst) : 2);
int32_t uip_compacted = brw_inst_uip(brw, insn) >> shift;
uip_compacted -= compacted_between(this_old_ip,
this_old_ip + uip_uncompacted,
this_old_ip + (uip_compacted / 2),
compacted_counts);
brw_inst_set_uip(brw, insn,
uip_compacted * (brw->gen >= 8 ? sizeof(brw_compact_inst) : 1));
brw_inst_set_uip(brw, insn, uip_compacted << shift);
}
static void
@ -1235,18 +1231,17 @@ update_gen4_jump_count(struct brw_context *brw, brw_inst *insn,
* - uncompacted instructions on G45; and
* - compacted instructions on Gen5.
*/
int jump_count = brw_inst_gen4_jump_count(brw, insn);
int jump_count_compacted = jump_count * (brw->is_g4x ? 2 : 1);
int jump_count_uncompacted = jump_count / (brw->is_g4x ? 1 : 2);
int shift = brw->is_g4x ? 1 : 0;
int target_old_ip = this_old_ip + jump_count_uncompacted;
int jump_count_compacted = brw_inst_gen4_jump_count(brw, insn) << shift;
int target_old_ip = this_old_ip + (jump_count_compacted / 2);
int this_compacted_count = compacted_counts[this_old_ip];
int target_compacted_count = compacted_counts[target_old_ip];
jump_count_compacted -= (target_compacted_count - this_compacted_count);
brw_inst_set_gen4_jump_count(brw, insn, jump_count_compacted /
(brw->is_g4x ? 2 : 1));
brw_inst_set_gen4_jump_count(brw, insn, jump_count_compacted >> shift);
}
void
@ -1421,9 +1416,8 @@ brw_compact_instructions(struct brw_compile *p, int start_offset,
/* Jump Count is in units of compacted instructions on Gen6. */
int jump_count_compacted = brw_inst_gen6_jump_count(brw, insn);
int jump_count_uncompacted = jump_count_compacted / 2;
target_old_ip = this_old_ip + jump_count_uncompacted;
target_old_ip = this_old_ip + (jump_count_compacted / 2);
target_compacted_count = compacted_counts[target_old_ip];
jump_count_compacted -= (target_compacted_count - this_compacted_count);
brw_inst_set_gen6_jump_count(brw, insn, jump_count_compacted);
@ -1444,15 +1438,13 @@ brw_compact_instructions(struct brw_compile *p, int start_offset,
brw_inst_dst_da_reg_nr(brw, insn) == BRW_ARF_IP) {
assert(brw_inst_src1_reg_file(brw, insn) == BRW_IMMEDIATE_VALUE);
int jump = brw_inst_imm_d(brw, insn);
int jump_compacted = jump / sizeof(brw_compact_inst);
int jump_uncompacted = jump / sizeof(brw_inst);
int shift = 3;
int jump_compacted = brw_inst_imm_d(brw, insn) >> shift;
target_old_ip = this_old_ip + jump_uncompacted;
target_old_ip = this_old_ip + (jump_compacted / 2);
target_compacted_count = compacted_counts[target_old_ip];
jump_compacted -= (target_compacted_count - this_compacted_count);
brw_inst_set_imm_ud(brw, insn, jump_compacted *
sizeof(brw_compact_inst));
brw_inst_set_imm_ud(brw, insn, jump_compacted << shift);
}
break;
}