From 996e968353f5b91cf8b7487998783ccba61de0d8 Mon Sep 17 00:00:00 2001 From: Jeff Law Date: Mon, 7 Dec 1998 15:38:24 -0700 Subject: [PATCH] local-alloc.c (block_alloc): Slightly retune heuristic to widen qty lifetimes. * local-alloc.c (block_alloc): Slightly retune heuristic to widen qty lifetimes. Actually check in the local-alloc patch that goes along with this ChangeLog entry... From-SVN: r24171 --- gcc/local-alloc.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/gcc/local-alloc.c b/gcc/local-alloc.c index f112713b284..f7d12d2e1e0 100644 --- a/gcc/local-alloc.c +++ b/gcc/local-alloc.c @@ -1414,8 +1414,8 @@ block_alloc (b) discourage the register allocator from creating false dependencies. - The adjustment by the value +-3 indicates precisely that - this qty conflicts with qtys in the instructions immediately + The adjustment value is choosen to indicate that this qty + conflicts with all the qtys in the instructions immediately before and after the lifetime of this qty. Experiments have shown that higher values tend to hurt @@ -1423,8 +1423,9 @@ block_alloc (b) If allocation using the extended lifetime fails we will try again with the qty's unadjusted lifetime. */ - int fake_birth = MAX (0, qty_birth[q] - 3); - int fake_death = MIN (insn_number * 2 + 1, qty_death[q] + 3); + int fake_birth = MAX (0, qty_birth[q] - 2 + qty_birth[q] % 2); + int fake_death = MIN (insn_number * 2 + 1, + qty_death[q] + 2 - qty_death[q] % 2); #endif if (N_REG_CLASSES > 1)