From 1d91f8d9164b38b4c924f43ec4fc5ceb65c96a78 Mon Sep 17 00:00:00 2001 From: Eric Anholt Date: Thu, 21 Oct 2010 16:54:03 -0700 Subject: i965: Be more aggressive in tracking live/dead intervals within loops. Fixes glsl-fs-convolution-2, which was blowing up due to the array access insanity getting at the uniform values within the loop. Each temporary was considered live across the whole loop. --- src/mesa/drivers/dri/i965/brw_fs.cpp | 54 +++++++++++++++++++++++++++--------- 1 file changed, 41 insertions(+), 13 deletions(-) diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp index aa945c9771..174f622d59 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp @@ -2441,6 +2441,7 @@ fs_visitor::calculate_live_intervals() int *use = talloc_array(mem_ctx, int, num_vars); int loop_depth = 0; int loop_start = 0; + int bb_header_ip = 0; for (int i = 0; i < num_vars; i++) { def[i] = 1 << 30; @@ -2458,12 +2459,8 @@ fs_visitor::calculate_live_intervals() loop_depth--; if (loop_depth == 0) { - /* FINISHME: - * - * Patches up any vars marked for use within the loop as - * live until the end. This is conservative, as there - * will often be variables defined and used inside the - * loop but dead at the end of the loop body. + /* Patches up the use of vars marked for being live across + * the whole loop. */ for (int i = 0; i < num_vars; i++) { if (use[i] == loop_start) { @@ -2472,22 +2469,53 @@ fs_visitor::calculate_live_intervals() } } } else { - int eip = ip; - - if (loop_depth) - eip = loop_start; - for (unsigned int i = 0; i < 3; i++) { if (inst->src[i].file == GRF && inst->src[i].reg != 0) { - use[inst->src[i].reg] = MAX2(use[inst->src[i].reg], eip); + int reg = inst->src[i].reg; + + if (!loop_depth || (this->virtual_grf_sizes[reg] == 1 && + def[reg] >= bb_header_ip)) { + use[reg] = ip; + } else { + def[reg] = MIN2(loop_start, def[reg]); + use[reg] = loop_start; + + /* Nobody else is going to go smash our start to + * later in the loop now, because def[reg] now + * points before the bb header. + */ + } } } if (inst->dst.file == GRF && inst->dst.reg != 0) { - def[inst->dst.reg] = MIN2(def[inst->dst.reg], eip); + int reg = inst->dst.reg; + + if (!loop_depth || (this->virtual_grf_sizes[reg] == 1 && + !inst->predicated)) { + def[reg] = MIN2(def[reg], ip); + } else { + def[reg] = MIN2(def[reg], loop_start); + } } } ip++; + + /* Set the basic block header IP. This is used for determining + * if a complete def of single-register virtual GRF in a loop + * dominates a use in the same basic block. It's a quick way to + * reduce the live interval range of most register used in a + * loop. + */ + if (inst->opcode == BRW_OPCODE_IF || + inst->opcode == BRW_OPCODE_ELSE || + inst->opcode == BRW_OPCODE_ENDIF || + inst->opcode == BRW_OPCODE_DO || + inst->opcode == BRW_OPCODE_WHILE || + inst->opcode == BRW_OPCODE_BREAK || + inst->opcode == BRW_OPCODE_CONTINUE) { + bb_header_ip = ip; + } } talloc_free(this->virtual_grf_def); -- cgit v1.2.3