get_reg(): try to free r2 for an SValue first

To be able to load a long long value correctly on i386, gv() rely on the
fact that when get_reg() look at an SValue it tries first to free the
register in r2 and then r. More information about the context can be
found at
http://lists.nongnu.org/archive/html/tinycc-devel/2012-06/msg00017.html
and later at
http://lists.nongnu.org/archive/html/tinycc-devel/2012-07/msg00021.html
This commit is contained in:
Thomas Preud'homme 2012-07-11 23:39:05 +02:00
parent ed9c6b132a
commit d1694f7d7e

View File

@ -589,11 +589,11 @@ ST_FUNC int get_reg(int rc)
IMPORTANT to start from the bottom to ensure that we don't
spill registers used in gen_opi()) */
for(p=vstack;p<=vtop;p++) {
r = p->r & VT_VALMASK;
/* look at second register (if long long) */
r = p->r2 & VT_VALMASK;
if (r < VT_CONST && (reg_classes[r] & rc))
goto save_found;
/* also look at second register (if long long) */
r = p->r2 & VT_VALMASK;
r = p->r & VT_VALMASK;
if (r < VT_CONST && (reg_classes[r] & rc)) {
save_found:
save_reg(r);
@ -812,7 +812,8 @@ ST_FUNC int gv(int rc)
vtop[-1].r = r; /* save register value */
vtop->r = vtop[-1].r2;
}
/* allocate second register */
/* Allocate second register. Here we rely on the fact that
get_reg() tries first to free r2 of an SValue. */
r2 = get_reg(rc2);
load(r2, vtop);
vpop();