http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60757
Bug ID: 60757 Summary: combine uses exponential time in nonzero_bits1 recursion Product: gcc Version: 4.9.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: rtl-optimization Assignee: unassigned at gcc dot gnu.org Reporter: amylaar at gcc dot gnu.org Created attachment 32540 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=32540&action=edit pruned down testcase With a small fix to the rtx_costs for epiphany, gcc.c-torture/compile/pr43415.c times out compiling at -O3. Even when the loop iteration counts are pruned, it's still too much, as nonzero_bits recurses for both operands of a binary operator... going through 40 operations means 2^40 paths being followed...