From: Aleksey Demakov <ademakov@gmail.com>
Date: Wed, 24 May 2006 18:56:32 +0000 (+0000)
Subject: fix spill cost calculation problem
X-Git-Tag: before.move.to.git~240
X-Git-Url: https://git.unchartedbackwaters.co.uk/w/?a=commitdiff_plain;h=abd8f6c4e5c037e256ab60109346b51724ec7eac;p=francis%2Flibjit.git

fix spill cost calculation problem
---

diff --git a/ChangeLog b/ChangeLog
index 9227aec..718623c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2006-05-25  Aleksey Demakov  <ademakov@gmail.com>
+
+	* jit/jit-reg-alloc.c (use_cheapest_register): fix cost calculation
+	that sometimes caused overlooking free registers. This was a serious
+	problem as there are some 'spill_before' rules that assume that the
+	allocator will always choose EAX as the first free register.
+
 2006-05-21  Aleksey Demakov  <ademakov@gmail.com>
 
 	* jit/jit-reg-alloc.h: add _JIT_REGS_FREE_DEST flag to be used in
diff --git a/jit/jit-reg-alloc.c b/jit/jit-reg-alloc.c
index cea4fe5..47f9011 100644
--- a/jit/jit-reg-alloc.c
+++ b/jit/jit-reg-alloc.c
@@ -2504,7 +2504,7 @@ use_cheapest_register(jit_gencode_t gen, _jit_regs_t *regs, int index, jit_regus
 		}
 		else
 		{
-			cost = 10 + compute_spill_cost(gen, regs, reg, other_reg);
+			cost = compute_spill_cost(gen, regs, reg, other_reg);
 		}
 
 		if(cost < suitable_cost
@@ -3562,6 +3562,7 @@ _jit_regs_init(_jit_regs_t *regs, int flags)
 	regs->on_stack = (flags & _JIT_REGS_STACK) != 0;
 	regs->x87_arith = (flags & _JIT_REGS_X87_ARITH) != 0;
 	regs->reversible = (flags & _JIT_REGS_REVERSIBLE) != 0;
+	regs->free_dest = (flags & _JIT_REGS_FREE_DEST) != 0;
 
 	regs->no_pop = 0;
 	regs->reverse_dest = 0;