From 4eb7284ef98c24331761cbe683c5bd89058e3ad3 Mon Sep 17 00:00:00 2001 From: Eric Anholt Date: Tue, 11 Jan 2011 15:13:49 -0800 Subject: [PATCH] i965: Tighten up the check for flow control interfering with coalescing. This greatly improves codegen for programs with flow control by allowing coalescing for all instructions at the top level, not just ones that follow the last flow control in the program. --- src/mesa/drivers/dri/i965/brw_fs.cpp | 38 +++++++++++++++++++--------- 1 file changed, 26 insertions(+), 12 deletions(-) diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp index 22e6e2e7368..35bce0f397c 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp @@ -2929,10 +2929,35 @@ bool fs_visitor::register_coalesce() { bool progress = false; + int if_depth = 0; + int loop_depth = 0; foreach_iter(exec_list_iterator, iter, this->instructions) { fs_inst *inst = (fs_inst *)iter.get(); + /* Make sure that we dominate the instructions we're going to + * scan for interfering with our coalescing, or we won't have + * scanned enough to see if anything interferes with our + * coalescing. We don't dominate the following instructions if + * we're in a loop or an if block. + */ + switch (inst->opcode) { + case BRW_OPCODE_DO: + loop_depth++; + break; + case BRW_OPCODE_WHILE: + loop_depth--; + break; + case BRW_OPCODE_IF: + if_depth++; + break; + case BRW_OPCODE_ENDIF: + if_depth--; + break; + } + if (loop_depth || if_depth) + continue; + if (inst->opcode != BRW_OPCODE_MOV || inst->predicated || inst->saturate || @@ -2950,14 +2975,6 @@ fs_visitor::register_coalesce() for (; scan_iter.has_next(); scan_iter.next()) { fs_inst *scan_inst = (fs_inst *)scan_iter.get(); - if (scan_inst->opcode == BRW_OPCODE_DO || - scan_inst->opcode == BRW_OPCODE_WHILE || - scan_inst->opcode == BRW_OPCODE_ENDIF) { - interfered = true; - iter = scan_iter; - break; - } - if (scan_inst->dst.file == GRF) { if (scan_inst->dst.reg == inst->dst.reg && (scan_inst->dst.reg_offset == inst->dst.reg_offset || @@ -2977,10 +2994,6 @@ fs_visitor::register_coalesce() continue; } - /* Update live interval so we don't have to recalculate. */ - this->virtual_grf_use[inst->src[0].reg] = MAX2(virtual_grf_use[inst->src[0].reg], - virtual_grf_use[inst->dst.reg]); - /* Rewrite the later usage to point at the source of the move to * be removed. */ @@ -3617,6 +3630,7 @@ brw_wm_fs_emit(struct brw_context *brw, struct brw_wm_compile *c) v.calculate_live_intervals(); progress = v.propagate_constants() || progress; progress = v.register_coalesce() || progress; + v.calculate_live_intervals(); progress = v.compute_to_mrf() || progress; progress = v.dead_code_eliminate() || progress; } while (progress); -- 2.30.2