From 7b91eefe7cbe771397684b5970f7c04313baa2f0 Mon Sep 17 00:00:00 2001 From: Eric Anholt Date: Mon, 8 Aug 2011 15:56:11 -0700 Subject: [PATCH] i965/vs: Slightly improve the trivial reg allocator to skip unused regs. This fixes most of the regressions in the vs array test set from the varying array indexing work, since the giant array that was originally allocated in virtual GRF space never gets used and is only ever read/stored from scratch space. --- .../dri/i965/brw_vec4_reg_allocate.cpp | 26 +++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-) diff --git a/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp b/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp index e7f6b28a536..1bfd84d76e8 100644 --- a/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp +++ b/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp @@ -41,15 +41,37 @@ vec4_visitor::reg_allocate_trivial() { int last_grf = 0; int hw_reg_mapping[this->virtual_grf_count]; + bool virtual_grf_used[this->virtual_grf_count]; int i; int next; + /* Calculate which virtual GRFs are actually in use after whatever + * optimization passes have occurred. + */ + for (int i = 0; i < this->virtual_grf_count; i++) { + virtual_grf_used[i] = false; + } + + foreach_iter(exec_list_iterator, iter, this->instructions) { + vec4_instruction *inst = (vec4_instruction *)iter.get(); + + if (inst->dst.file == GRF) + virtual_grf_used[inst->dst.reg] = true; + + for (int i = 0; i < 3; i++) { + if (inst->src[i].file == GRF) + virtual_grf_used[inst->src[i].reg] = true; + } + } + /* Note that compressed instructions require alignment to 2 registers. */ hw_reg_mapping[0] = this->first_non_payload_grf; next = hw_reg_mapping[0] + this->virtual_grf_sizes[0]; for (i = 1; i < this->virtual_grf_count; i++) { - hw_reg_mapping[i] = next; - next += this->virtual_grf_sizes[i]; + if (virtual_grf_used[i]) { + hw_reg_mapping[i] = next; + next += this->virtual_grf_sizes[i]; + } } prog_data->total_grf = next; -- 2.30.2