| Message ID | CAO2gOZX-YhBDxZmEGXztty6H+KAdbKtpPhyY5betB0tHj0dhwQ@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
On Sat, Jun 22, 2013 at 2:59 AM, Dehao Chen <dehao@google.com> wrote: > This patch prevents integer-underflow of badness computation in ipa-inline. > > Bootstrapped and passed regression tests. > > OK for trunk? > > Thanks, > Dehao > > gcc/ChangeLog: > 2013-06-21 Dehao Chen <dehao@google.com> > > * ipa-inline.c (edge_badness): Fix integer underflow. > > Index: gcc/ipa-inline.c > =================================================================== > --- gcc/ipa-inline.c (revision 200326) > +++ gcc/ipa-inline.c (working copy) > @@ -888,11 +888,9 @@ edge_badness (struct cgraph_edge *edge, bool dump) > else if (max_count) > { > int relbenefit = relative_time_benefit (callee_info, edge, edge_time); > - badness = > - ((int) > - ((double) edge->count * INT_MIN / 2 / max_count / > RELATIVE_TIME_BENEFIT_RANGE) * > - relbenefit) / growth; > - > + badness = ((int)((double) edge->count / max_count > + * relbenefit / RELATIVE_TIME_BENEFIT_RANGE * INT_MIN / 2)) / growth; > + FP operations on the host are frowned upon if code generation depends on their outcome. They all should use sreal_* as predict already does. Other than that I wonder why the final division is int (so we get truncation and not rounding)? That increases the effect of doing the multiply by relbenefit in double. Richard. > /* Be sure that insanity of the profile won't lead to increasing counts > in the scalling and thus to overflow in the computation above. */ > gcc_assert (max_count >= edge->count);
Index: gcc/ipa-inline.c =================================================================== --- gcc/ipa-inline.c (revision 200326) +++ gcc/ipa-inline.c (working copy) @@ -888,11 +888,9 @@ edge_badness (struct cgraph_edge *edge, bool dump) else if (max_count) { int relbenefit = relative_time_benefit (callee_info, edge, edge_time); - badness = - ((int) - ((double) edge->count * INT_MIN / 2 / max_count / RELATIVE_TIME_BENEFIT_RANGE) * - relbenefit) / growth; - + badness = ((int)((double) edge->count / max_count + * relbenefit / RELATIVE_TIME_BENEFIT_RANGE * INT_MIN / 2)) / growth; + /* Be sure that insanity of the profile won't lead to increasing counts in the scalling and thus to overflow in the computation above. */
This patch prevents integer-underflow of badness computation in ipa-inline. Bootstrapped and passed regression tests. OK for trunk? Thanks, Dehao gcc/ChangeLog: 2013-06-21 Dehao Chen <dehao@google.com> * ipa-inline.c (edge_badness): Fix integer underflow. gcc_assert (max_count >= edge->count);