i965/fs: Also do the gen4 SEND dependency workaround against other SENDs.

We were handling the the dependency workaround for the first written reg
of a send preceding the one we're fixing up, but didn't consider the other
regs.  Thus if you had two sampler calls that got allocated to the same
set of regs, one might, rarely, ovewrite the other.  This was occurring in
XBMC's GLSL shaders.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=44567
NOTE: This is a candidate for the stable branches.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
(cherry picked from commit 4dc7e6dcbf)
This commit is contained in:
Eric Anholt 2013-03-06 17:50:50 -08:00 committed by Ian Romanick
parent c5bc65bd62
commit ff27e18834

View file

@ -2295,7 +2295,8 @@ clear_deps_for_inst_src(fs_inst *inst, int dispatch_width, bool *deps,
void
fs_visitor::insert_gen4_pre_send_dependency_workarounds(fs_inst *inst)
{
int write_len = inst->regs_written() * dispatch_width / 8;
int reg_size = dispatch_width / 8;
int write_len = inst->regs_written() * reg_size;
int first_write_grf = inst->dst.reg;
bool needs_dep[BRW_MAX_MRF];
assert(write_len < (int)sizeof(needs_dep) - 1);
@ -2334,14 +2335,19 @@ fs_visitor::insert_gen4_pre_send_dependency_workarounds(fs_inst *inst)
* instruction but a MOV that might have left us an outstanding
* dependency has more latency than a MOV.
*/
if (scan_inst->dst.file == GRF &&
scan_inst->dst.reg >= first_write_grf &&
scan_inst->dst.reg < first_write_grf + write_len &&
needs_dep[scan_inst->dst.reg - first_write_grf]) {
inst->insert_before(DEP_RESOLVE_MOV(scan_inst->dst.reg));
needs_dep[scan_inst->dst.reg - first_write_grf] = false;
if (scan_inst_16wide)
needs_dep[scan_inst->dst.reg - first_write_grf + 1] = false;
if (scan_inst->dst.file == GRF) {
for (int i = 0; i < scan_inst->regs_written(); i++) {
int reg = scan_inst->dst.reg + i * reg_size;
if (reg >= first_write_grf &&
reg < first_write_grf + write_len &&
needs_dep[reg - first_write_grf]) {
inst->insert_before(DEP_RESOLVE_MOV(reg));
needs_dep[reg - first_write_grf] = false;
if (scan_inst_16wide)
needs_dep[reg - first_write_grf + 1] = false;
}
}
}
/* Clear the flag for registers that actually got read (as expected). */