This marks GTY bitmaps properly for most efficient marking. Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard. 2012-08-17 Richard Guenther <rguent...@suse.de> * bitmap.h (struct bitmap_element_def): GTY annotate next/prev. (struct bitmap_head_def): GTY skip current field. Index: gcc/bitmap.h =================================================================== --- gcc/bitmap.h (revision 190471) +++ gcc/bitmap.h (working copy) @@ -167,9 +167,9 @@ typedef struct GTY (()) bitmap_obstack { bitmap_elt_clear_from to be implemented in unit time rather than linear in the number of elements to be freed. */ -typedef struct GTY(()) bitmap_element_def { - struct bitmap_element_def *next; /* Next element. */ - struct bitmap_element_def *prev; /* Previous element. */ +typedef struct GTY((chain_next ("%h.next"), chain_prev ("%h.prev"))) bitmap_element_def { + struct bitmap_element_def *next; /* Next element. */ + struct bitmap_element_def *prev; /* Previous element. */ unsigned int indx; /* regno/BITMAP_ELEMENT_ALL_BITS. */ BITMAP_WORD bits[BITMAP_ELEMENT_WORDS]; /* Bits that are set. */ } bitmap_element; @@ -177,15 +177,17 @@ typedef struct GTY(()) bitmap_element_de struct bitmap_descriptor; /* Head of bitmap linked list. gengtype ignores ifdefs, but for statistics we need to add a bitmap descriptor pointer. As it is - not collected, we can just GTY((skip)) it. */ + not collected, we can just GTY((skip(""))) it. Likewise current + points to something already pointed to by the chain started by first, + no need to walk it again. */ typedef struct GTY(()) bitmap_head_def { - bitmap_element *first; /* First element in linked list. */ - bitmap_element *current; /* Last element looked at. */ - unsigned int indx; /* Index of last element looked at. */ - bitmap_obstack *obstack; /* Obstack to allocate elements from. - If NULL, then use GGC allocation. */ - struct bitmap_descriptor GTY((skip)) *desc; + bitmap_element *first; /* First element in linked list. */ + bitmap_element * GTY((skip(""))) current; /* Last element looked at. */ + unsigned int indx; /* Index of last element looked at. */ + bitmap_obstack *obstack; /* Obstack to allocate elements from. + If NULL, then use GGC allocation. */ + struct bitmap_descriptor GTY((skip(""))) *desc; } bitmap_head; /* Global data */