https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69344
Bug ID: 69344 Summary: [6 Regression] 435.gromacs regression Product: gcc Version: 6.0 Status: UNCONFIRMED Keywords: missed-optimization Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: rguenth at gcc dot gnu.org Target Milestone: --- Target: x86_64-*-* Our two SPEC 2k6 testers show recent (mid December) regressions for 435.gromacs: http://gcc.opensuse.org/SPEC/CFP/sb-czerny-head-64-2006/index.html http://gcc.opensuse.org/SPEC/CFP/sb-megrez-head-64-2006/index.html which can be narrowed down to r231790 (last good) r231841 (first known bad) for the first link and r231805 (last good) r231814 (first known bad) for the second. Both testers use -Ofast -march=native, one is corei-avx2 one bdver2 This effectively means (given gromas is C only) I'd blame r231814 which is 2015-12-18 Andreas Krebbel <kreb...@linux.vnet.ibm.com> * ira.c (ira_setup_alts): Move the scan for commutative modifier to the first loop to make it work even with disabled alternatives. but this means it is a backend issue. Didn't yet try narrowing down to a testcase or try confirming the causing revision.