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rb_tree: optimize tree rotation

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The RB_ROTATE macros begin with fetching a field via a pointer. In
most cases, that value is one that has already been pulled into a
register, and the compiler cannot infer that. So, to eliminate those
needless fetches, have the caller of the RB_ROTATE macros present the
data in the third macro parameter, rather than having the macro fetch
it.

Differential Revision:	https://reviews.freebsd.org/D35520
This commit is contained in:
Doug Moore 2022-06-25 02:40:16 -05:00
parent e3b31e23ff
commit 61c74fb66f
1 changed files with 4 additions and 2 deletions
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6
sys/sys/tree.h
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@ -380,7 +380,6 @@ struct { \
} while (/*CONSTCOND*/ 0)
#define RB_ROTATE_LEFT(head, elm, tmp, field) do { \
(tmp) = RB_RIGHT(elm, field); \
if ((RB_RIGHT(elm, field) = RB_LEFT(tmp, field)) != NULL) { \
RB_SET_PARENT(RB_RIGHT(elm, field), elm, field); \
} \
@ -392,7 +391,6 @@ struct { \
} while (/*CONSTCOND*/ 0)
#define RB_ROTATE_RIGHT(head, elm, tmp, field) do { \
(tmp) = RB_LEFT(elm, field); \
if ((RB_LEFT(elm, field) = RB_RIGHT(tmp, field)) != NULL) { \
RB_SET_PARENT(RB_LEFT(elm, field), elm, field); \
} \
@ -473,6 +471,7 @@ name##_RB_INSERT_COLOR(struct name *head, struct type *elm) \
} \
RB_FLIP_RIGHT(parent, field); \
if (RB_RED_RIGHT(parent, field)) { \
child = elm; \
elm = parent; \
continue; \
} \
@ -493,6 +492,7 @@ name##_RB_INSERT_COLOR(struct name *head, struct type *elm) \
} \
RB_FLIP_LEFT(parent, field); \
if (RB_RED_LEFT(parent, field)) { \
child = elm; \
elm = parent; \
continue; \
} \
@ -548,6 +548,7 @@ name##_RB_REMOVE_COLOR(struct name *head, \
RB_FLIP_LEFT(parent, field); \
else if (!RB_RED_RIGHT(sib, field)) { \
RB_FLIP_LEFT(parent, field); \
elm = RB_LEFT(sib, field); \
RB_ROTATE_RIGHT(head, sib, elm, field); \
if (RB_RED_RIGHT(elm, field)) \
RB_FLIP_LEFT(sib, field); \
@ -578,6 +579,7 @@ name##_RB_REMOVE_COLOR(struct name *head, \
RB_FLIP_RIGHT(parent, field); \
else if (!RB_RED_LEFT(sib, field)) { \
RB_FLIP_RIGHT(parent, field); \
elm = RB_RIGHT(sib, field); \
RB_ROTATE_LEFT(head, sib, elm, field); \
if (RB_RED_LEFT(elm, field)) \
RB_FLIP_RIGHT(sib, field); \