intel/fs: Relax type matching rules in cmod propagation from MOV instructions

To allow cmod propagation from a MOV 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

A similar change to the vec4 backend had no effect.

Somewhere between c1ec582059 and 40fc4b5acd (1,094 commits) the
effectiveness of this patch diminished, and as of commit d7e0d47b9d
(nir: Add a bunch of b2[if] optimizations) this optimization no longer
has any effect on any platform.

A later patch "intel/fs: Use De Morgan's laws to avoid logical-not of a
logic result on Gen8+," generates some instruction sequences that
require this change in order for cmod propagation to make progress.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
This commit is contained in:
Ian Romanick
2018-06-19 13:34:57 -07:00
parent eae19f5f19
commit c9d5bd050c

View File

@@ -263,10 +263,25 @@ opt_cmod_propagation_local(const gen_device_info *devinfo, bblock_t *block)
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))
if (scan_inst->dst.type != inst->dst.type) {
/* 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 (scan_inst->dst.type == BRW_REGISTER_TYPE_F ||
inst->dst.type == BRW_REGISTER_TYPE_F) {
break;
}
}
/* If the instruction generating inst's source also wrote the
* flag, and inst is doing a simple .nz comparison, then inst