From 6a0a4c31e872d3ef97ef084da9c0ead37248bc30 Mon Sep 17 00:00:00 2001 From: nickc Date: Fri, 31 Aug 2007 14:28:38 +0000 Subject: * tree-ssa-coalesce.c (compare_pairs): Use the elements as secondary keys in order to obtain a stable sort. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@127993 138bc75d-0d04-0410-961f-82ee72b054a4 --- gcc/tree-ssa-coalesce.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) (limited to 'gcc/tree-ssa-coalesce.c') diff --git a/gcc/tree-ssa-coalesce.c b/gcc/tree-ssa-coalesce.c index 1b63635881b..ef1ebcab4a9 100644 --- a/gcc/tree-ssa-coalesce.c +++ b/gcc/tree-ssa-coalesce.c @@ -314,8 +314,22 @@ add_coalesce (coalesce_list_p cl, int p1, int p2, static int compare_pairs (const void *p1, const void *p2) { - return (*(const_coalesce_pair_p const*)p1)->cost - - (*(const_coalesce_pair_p const*)p2)->cost; + const_coalesce_pair_p const * pp1 = p1; + const_coalesce_pair_p const * pp2 = p2; + int result; + + result = (* pp2)->cost - (* pp1)->cost; + /* Since qsort does not guarantee stability we use the elements + as a secondary key. This provides us with independence from + the host's implementation of the sorting algorithm. */ + if (result == 0) + { + result = (* pp2)->first_element - (* pp1)->first_element; + if (result == 0) + result = (* pp2)->second_element - (* pp1)->second_element; + } + + return result; } -- cgit v1.2.1