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| author | Nick Clifton <nickc@redhat.com> | 2007-08-31 14:28:38 +0000 |
|---|---|---|
| committer | Nick Clifton <nickc@gcc.gnu.org> | 2007-08-31 14:28:38 +0000 |
| commit | 7562df8122d83aa86ddbc2e096a96ef16e85045f (patch) | |
| tree | 186057dc0dca9f422aab0bbbc925c792aee79361 /gcc/tree-ssa-coalesce.c | |
| parent | 3681df8fe1eac5d26deefddeb621d2d74bbf5bb9 (diff) | |
| download | gcc-7562df8122d83aa86ddbc2e096a96ef16e85045f.zip gcc-7562df8122d83aa86ddbc2e096a96ef16e85045f.tar.gz gcc-7562df8122d83aa86ddbc2e096a96ef16e85045f.tar.bz2 | |
tree-ssa-coalesce.c (compare_pairs): Use the elements as secondary keys in order to obtain a stable sort.
* tree-ssa-coalesce.c (compare_pairs): Use the elements as secondary keys
in order to obtain a stable sort.
From-SVN: r127993
Diffstat (limited to 'gcc/tree-ssa-coalesce.c')
| -rw-r--r-- | gcc/tree-ssa-coalesce.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/gcc/tree-ssa-coalesce.c b/gcc/tree-ssa-coalesce.c index 1b63635..ef1ebca 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; } |