fs_inst *inst)
{
bool read_flag = false;
+ const unsigned flags_written = inst->flags_written();
foreach_inst_in_block_reverse_starting_from(fs_inst, scan_inst, inst) {
if (scan_inst->opcode == BRW_OPCODE_ADD &&
goto not_match;
}
+ /* If the scan instruction writes a different flag register than the
+ * instruction we're trying to propagate from, bail.
+ *
+ * FINISHME: The second part of the condition may be too strong.
+ * Perhaps (scan_inst->flags_written() & flags_written) !=
+ * flags_written?
+ */
+ if (scan_inst->flags_written() != 0 &&
+ scan_inst->flags_written() != flags_written)
+ goto not_match;
+
/* From the Sky Lake PRM Vol. 7 "Assigning Conditional Mods":
*
* * Note that the [post condition signal] bits generated at
}
not_match:
- if (scan_inst->flags_written())
+ if ((scan_inst->flags_written() & flags_written) != 0)
break;
- read_flag = read_flag || scan_inst->flags_read(devinfo);
+ read_flag = read_flag ||
+ (scan_inst->flags_read(devinfo) & flags_written) != 0;
}
return false;
{
const enum brw_conditional_mod cond = brw_negate_cmod(inst->conditional_mod);
bool read_flag = false;
+ const unsigned flags_written = inst->flags_written();
if (cond != BRW_CONDITIONAL_Z && cond != BRW_CONDITIONAL_NZ)
return false;
scan_inst->exec_size != inst->exec_size)
break;
+ /* If the scan instruction writes a different flag register than the
+ * instruction we're trying to propagate from, bail.
+ *
+ * FINISHME: The second part of the condition may be too strong.
+ * Perhaps (scan_inst->flags_written() & flags_written) !=
+ * flags_written?
+ */
+ if (scan_inst->flags_written() != 0 &&
+ scan_inst->flags_written() != flags_written)
+ break;
+
if (scan_inst->can_do_cmod() &&
((!read_flag && scan_inst->conditional_mod == BRW_CONDITIONAL_NONE) ||
scan_inst->conditional_mod == cond)) {
break;
}
- if (scan_inst->flags_written())
+ if ((scan_inst->flags_written() & flags_written) != 0)
break;
- read_flag = read_flag || scan_inst->flags_read(devinfo);
+ read_flag = read_flag ||
+ (scan_inst->flags_read(devinfo) & flags_written) != 0;
}
return false;
/* A CMP with a second source of zero can match with anything. A CMP
* with a second source that is not zero can only match with an ADD
* instruction.
+ *
+ * Only apply this optimization to float-point sources. It can fail for
+ * integers. For inputs a = 0x80000000, b = 4, int(0x80000000) < 4, but
+ * int(0x80000000) - 4 overflows and results in 0x7ffffffc. that's not
+ * less than zero, so the flags get set differently than for (a < b).
*/
if (inst->opcode == BRW_OPCODE_CMP && !inst->src[1].is_zero()) {
- progress = cmod_propagate_cmp_to_add(devinfo, block, inst) || progress;
+ if (brw_reg_type_is_floating_point(inst->src[0].type) &&
+ cmod_propagate_cmp_to_add(devinfo, block, inst))
+ progress = true;
+
continue;
}
}
bool read_flag = false;
+ const unsigned flags_written = inst->flags_written();
foreach_inst_in_block_reverse_starting_from(fs_inst, scan_inst, inst) {
if (regions_overlap(scan_inst->dst, scan_inst->size_written,
inst->src[0], inst->size_read(0))) {
+ /* If the scan instruction writes a different flag register than
+ * the instruction we're trying to propagate from, bail.
+ *
+ * FINISHME: The second part of the condition may be too strong.
+ * Perhaps (scan_inst->flags_written() & flags_written) !=
+ * flags_written?
+ */
+ if (scan_inst->flags_written() != 0 &&
+ scan_inst->flags_written() != flags_written)
+ break;
+
if (scan_inst->is_partial_write() ||
scan_inst->dst.offset != inst->src[0].offset ||
scan_inst->exec_size != inst->exec_size)
/* CMP's result is the same regardless of dest type. */
if (inst->conditional_mod == BRW_CONDITIONAL_NZ &&
scan_inst->opcode == BRW_OPCODE_CMP &&
- (inst->dst.type == BRW_REGISTER_TYPE_D ||
- inst->dst.type == BRW_REGISTER_TYPE_UD)) {
+ brw_reg_type_is_integer(inst->dst.type)) {
inst->remove(block);
progress = true;
break;
if (inst->opcode == BRW_OPCODE_AND)
break;
- /* Comparisons operate differently for ints and floats */
- if (scan_inst->dst.type != inst->dst.type &&
- (scan_inst->dst.type == BRW_REGISTER_TYPE_F ||
- inst->dst.type == BRW_REGISTER_TYPE_F))
+ /* Not safe to use inequality operators if the types are different
+ */
+ if (scan_inst->dst.type != inst->src[0].type &&
+ inst->conditional_mod != BRW_CONDITIONAL_Z &&
+ inst->conditional_mod != BRW_CONDITIONAL_NZ)
break;
+ /* Comparisons operate differently for ints and floats */
+ if (scan_inst->dst.type != inst->dst.type) {
+ /* Comparison result may be altered if the bit-size changes
+ * since that affects range, denorms, etc
+ */
+ if (type_sz(scan_inst->dst.type) != type_sz(inst->dst.type))
+ break;
+
+ /* We should propagate from a MOV to another instruction in a
+ * sequence like:
+ *
+ * and(16) g31<1>UD g20<8,8,1>UD g22<8,8,1>UD
+ * mov.nz.f0(16) null<1>F g31<8,8,1>D
+ */
+ if (inst->opcode == BRW_OPCODE_MOV) {
+ if ((inst->src[0].type != BRW_REGISTER_TYPE_D &&
+ inst->src[0].type != BRW_REGISTER_TYPE_UD) ||
+ (scan_inst->dst.type != BRW_REGISTER_TYPE_D &&
+ scan_inst->dst.type != BRW_REGISTER_TYPE_UD)) {
+ break;
+ }
+ } else if (brw_reg_type_is_floating_point(scan_inst->dst.type) !=
+ brw_reg_type_is_floating_point(inst->dst.type)) {
+ break;
+ }
+ }
+
/* If the instruction generating inst's source also wrote the
* flag, and inst is doing a simple .nz comparison, then inst
* is redundant - the appropriate value is already in the flag
scan_inst->opcode == BRW_OPCODE_CMPN)
break;
- /* From the Sky Lake PRM Vol. 7 "Assigning Conditional Mods":
- *
- * * Note that the [post condition signal] bits generated at
- * the output of a compute are before the .sat.
- */
- if (scan_inst->saturate)
- break;
-
/* From the Sky Lake PRM, Vol 2a, "Multiply":
*
* "When multiplying integer data types, if one of the sources
scan_inst->opcode == BRW_OPCODE_MUL)
break;
- /* Otherwise, try propagating the conditional. */
enum brw_conditional_mod cond =
inst->src[0].negate ? brw_swap_cmod(inst->conditional_mod)
: inst->conditional_mod;
+ /* From the Sky Lake PRM Vol. 7 "Assigning Conditional Mods":
+ *
+ * * Note that the [post condition signal] bits generated at
+ * the output of a compute are before the .sat.
+ *
+ * This limits the cases where we can propagate the conditional
+ * modifier. If scan_inst has a saturate modifier, then we can
+ * only propagate from inst if inst is 'scan_inst <= 0',
+ * 'scan_inst == 0', 'scan_inst != 0', or 'scan_inst > 0'. If
+ * inst is 'scan_inst == 0', the conditional modifier must be
+ * replace with LE. Likewise, if inst is 'scan_inst != 0', the
+ * conditional modifier must be replace with G.
+ *
+ * The only other cases are 'scan_inst < 0' (which is a
+ * contradiction) and 'scan_inst >= 0' (which is a tautology).
+ */
+ if (scan_inst->saturate) {
+ if (scan_inst->dst.type != BRW_REGISTER_TYPE_F)
+ break;
+
+ if (cond != BRW_CONDITIONAL_Z &&
+ cond != BRW_CONDITIONAL_NZ &&
+ cond != BRW_CONDITIONAL_LE &&
+ cond != BRW_CONDITIONAL_G)
+ break;
+
+ if (inst->opcode != BRW_OPCODE_MOV &&
+ inst->opcode != BRW_OPCODE_CMP)
+ break;
+
+ /* inst->src[1].is_zero() was tested before, but be safe
+ * against possible future changes in this code.
+ */
+ assert(inst->opcode != BRW_OPCODE_CMP || inst->src[1].is_zero());
+
+ if (cond == BRW_CONDITIONAL_Z)
+ cond = BRW_CONDITIONAL_LE;
+ else if (cond == BRW_CONDITIONAL_NZ)
+ cond = BRW_CONDITIONAL_G;
+ }
+
+ /* Otherwise, try propagating the conditional. */
if (scan_inst->can_do_cmod() &&
((!read_flag && scan_inst->conditional_mod == BRW_CONDITIONAL_NONE) ||
scan_inst->conditional_mod == cond)) {
scan_inst->conditional_mod = cond;
+ scan_inst->flag_subreg = inst->flag_subreg;
inst->remove(block);
progress = true;
}
break;
}
- if (scan_inst->flags_written())
+ if ((scan_inst->flags_written() & flags_written) != 0)
break;
- read_flag = read_flag || scan_inst->flags_read(devinfo);
+ read_flag = read_flag ||
+ (scan_inst->flags_read(devinfo) & flags_written) != 0;
}
}
projects / mesa.git / blobdiff