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tree-ssa-coalesce.c (compare_pairs): Use the elements as secondary keys in order to obtain a stable sort.

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* tree-ssa-coalesce.c (compare_pairs): Use the elements as secondary keys 
  in order to obtain a stable sort.

From-SVN: r127993
This commit is contained in:
Nick Clifton 2007-08-31 14:28:38 +00:00 • committed by Nick Clifton
parent 3681df8fe1
commit 7562df8122
2 changed files with 21 additions and 2 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2007-08-31 Nick Clifton <nickc@redhat.com>
* tree-ssa-coalesce.c (compare_pairs): Use the elements as
secondary keys in order to obtain a stable sort.
2007-08-31 Nick Clifton <nickc@redhat.com>
PR target/33132

18
gcc/tree-ssa-coalesce.c
View file

@ -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;
}