diff options
Diffstat (limited to 'src/util/register_allocate.c')
| -rw-r--r-- | src/util/register_allocate.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/src/util/register_allocate.c b/src/util/register_allocate.c index 684ee5d6cf5..2ad8c3ce11a 100644 --- a/src/util/register_allocate.c +++ b/src/util/register_allocate.c @@ -168,6 +168,12 @@ struct ra_graph { unsigned int *stack; unsigned int stack_count; + + /** + * Tracks the start of the set of optimistically-colored registers in the + * stack. + */ + unsigned int stack_optimistic_start; }; /** @@ -454,6 +460,7 @@ static void ra_simplify(struct ra_graph *g) { bool progress = true; + unsigned int stack_optimistic_start = UINT_MAX; int i; while (progress) { @@ -482,6 +489,9 @@ ra_simplify(struct ra_graph *g) } if (!progress && best_optimistic_node != ~0U) { + if (stack_optimistic_start == UINT_MAX) + stack_optimistic_start = g->stack_count; + decrement_q(g, best_optimistic_node); g->stack[g->stack_count] = best_optimistic_node; g->stack_count++; @@ -489,6 +499,8 @@ ra_simplify(struct ra_graph *g) progress = true; } } + + g->stack_optimistic_start = stack_optimistic_start; } /** @@ -542,7 +554,17 @@ ra_select(struct ra_graph *g) g->nodes[n].reg = r; g->stack_count--; - if (g->regs->round_robin) + /* Rotate the starting point except for any nodes above the lowest + * optimistically colorable node. The likelihood that we will succeed + * at allocating optimistically colorable nodes is highly dependent on + * the way that the previous nodes popped off the stack are laid out. + * The round-robin strategy increases the fragmentation of the register + * file and decreases the number of nearby nodes assigned to the same + * color, what increases the likelihood of spilling with respect to the + * dense packing strategy. + */ + if (g->regs->round_robin && + g->stack_count - 1 <= g->stack_optimistic_start) start_search_reg = r + 1; } |