From 041e059f264744313dc38f2223098409f8d86c29 Mon Sep 17 00:00:00 2001 From: Xinliang David Li Date: Fri, 8 Apr 2011 21:03:12 +0000 Subject: [PATCH] FDO insane profile From-SVN: r172213 --- gcc/ChangeLog | 5 +++++ gcc/ipa-cp.c | 23 +++++++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 3abeed0c0fd..6d7b9073176 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2011-04-08 Xinliang David Li + + * ipa-cp.c (ipcp_update_profiling): Correct + negative scale factor due to insane profile data. + 2011-04-08 Xinliang David Li * final.c (dump_basic_block_info): New function. diff --git a/gcc/ipa-cp.c b/gcc/ipa-cp.c index db0941c36a3..2b1e50dcb61 100644 --- a/gcc/ipa-cp.c +++ b/gcc/ipa-cp.c @@ -1113,6 +1113,29 @@ ipcp_update_profiling (void) scale = ipcp_get_node_scale (orig_node); node->count = orig_node->count * scale / REG_BR_PROB_BASE; scale_complement = REG_BR_PROB_BASE - scale; + + /* Negative scale complement can result from insane profile data + in which the total incoming edge counts in this module is + larger than the callee's entry count. The insane profile data + usually gets generated due to the following reasons: + + 1) in multithreaded programs, when profile data is dumped + to gcda files in gcov_exit, some other threads are still running. + The profile counters are dumped in bottom up order (call graph). + The caller's BB counters may still be updated while the callee's + counter data is already saved to disk. + + 2) Comdat functions: comdat functions' profile data are not + allocated in comdat. When a comdat callee function gets inlined + at some callsites after instrumentation, and the remaining calls + to this function resolves to a comdat copy in another module, + the profile counters for this function are split. This can + result in sum of incoming edge counts from this module being + larger than callee instance's entry count. */ + + if (scale_complement < 0 && flag_profile_correction) + scale_complement = 0; + orig_node->count = orig_node->count * scale_complement / REG_BR_PROB_BASE; for (cs = node->callees; cs; cs = cs->next_callee)