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optimize (let ([x (let~ ([y M]) N)]) P) to (let~ ([y M]) (let ([x N]) P))

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which helps expose unboxing opportunities with multiple-value binding
This commit is contained in:
Matthew Flatt 2010-08-11 10:24:06 -06:00
parent a6ec6a7e30
commit e9269f1c4a
1 changed files with 40 additions and 21 deletions
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61
src/racket/src/syntax.c
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@ -3132,28 +3132,46 @@ scheme_optimize_lets(Scheme_Object *form, Optimize_Info *info, int for_inline, i
is_rec = (SCHEME_LET_FLAGS(head) & SCHEME_LET_RECURSIVE);
#if 0
if (!is_rec) {
/* (let ([x (let ([y M]) N)]) P) => (let ([y M]) (let ([x N]) P)) */
if (head->count == 1) {
clv = (Scheme_Compiled_Let_Value *)head->body; /* ([x ...]) */
if (SAME_TYPE(SCHEME_TYPE(clv->value), scheme_compiled_let_void_type)) {
Scheme_Let_Header *lh = (Scheme_Let_Header *)clv->value; /* (let ([y ...]) ...) */
if (!(SCHEME_LET_FLAGS(lh) & SCHEME_LET_RECURSIVE)
&& (lh->count == 1)) {
value = ((Scheme_Compiled_Let_Value *)lh->body)->body; /* = N */
((Scheme_Compiled_Let_Value *)lh->body)->body = (Scheme_Object *)head;
clv->value = value;
head = lh;
form = (Scheme_Obejct *)head;
int try_again;
do {
try_again = 0;
/* (let ([x (let~ ([y M]) N)]) P) => (let~ ([y M]) (let ([x N]) P)) */
if (post_bind) {
if (head->num_clauses == 1) {
clv = (Scheme_Compiled_Let_Value *)head->body; /* ([x ...]) */
if (SAME_TYPE(SCHEME_TYPE(clv->value), scheme_compiled_let_void_type)) {
Scheme_Let_Header *lh = (Scheme_Let_Header *)clv->value; /* (let~ ([y ...]) ...) */
orig_info = info;
info = scheme_optimize_info_add_frame(info, 1, 0, 0);
value = clv->body; /* = P */
if (lh->count)
value = scheme_optimize_shift(value, lh->count, head->count);
if (value) {
clv->body = value;
if (!lh->num_clauses) {
clv->value = lh->body;
lh->body = (Scheme_Object *)head;
} else {
body = lh->body;
for (i = lh->num_clauses - 1; i--; ) {
body = ((Scheme_Compiled_Let_Value *)body)->body;
}
clv->value = ((Scheme_Compiled_Let_Value *)body)->body; /* N */
((Scheme_Compiled_Let_Value *)body)->body = (Scheme_Object *)head;
}
head = lh;
form = (Scheme_Object *)head;
is_rec = (SCHEME_LET_FLAGS(head) & SCHEME_LET_RECURSIVE);
post_bind = !(SCHEME_LET_FLAGS(head) & (SCHEME_LET_RECURSIVE | SCHEME_LET_STAR));
try_again = 1;
}
}
}
}
}
} while (try_again);
}
#endif
split_shift = 0;
if (is_rec) {
@ -3201,15 +3219,16 @@ scheme_optimize_lets(Scheme_Object *form, Optimize_Info *info, int for_inline, i
body_info = scheme_optimize_info_add_frame(info, head->count, head->count,
post_bind ? SCHEME_POST_BIND_FRAME : 0);
if (post_bind) {
if (post_bind)
rhs_info = scheme_optimize_info_add_frame(info, 0, 0, 0);
if (for_inline)
body_info->inline_fuel >>= 1;
} else if (split_shift)
else if (split_shift)
rhs_info = scheme_optimize_info_add_frame(body_info, split_shift, 0, 0);
else
rhs_info = body_info;
if (for_inline)
body_info->inline_fuel >>= 1;
body = head->body;
for (i = head->num_clauses; i--; ) {
pre_body = (Scheme_Compiled_Let_Value *)body;