[Bug ipa/65873] [5/6 Regression] Failure to inline always_inline memcpy

hubicka at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Mon Apr 27 08:05:00 GMT 2015


--- Comment #1 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
The diff in flags is the following:

  not inlinable: bar/1 -> memcpy/0, optimization level attribute mismatch       

  align_functions (0/0x10)                                                      
  align_jumps (0/0x10)                                                          
  align_loops (0/0x10)                                                          
  flag_vect_cost_model (0x2/0x1)                                                
  optimize (0x3/0x2)                                                            
  flag_associative_math (0x1/0)                                                 
  flag_cx_limited_range (0x1/0)                                                 
  flag_finite_math_only (0x1/0)                                                 
  flag_gcse_after_reload (0x1/0)                                                
  flag_inline_functions (0x1/0)                                                 
  flag_ipa_cp_clone (0x1/0)                                                     
  flag_errno_math (0/0x1)                                                       
  flag_predictive_commoning (0x1/0)                                             
  flag_reciprocal_math (0x1/0)                                                  
  flag_signed_zeros (0/0x1)                                                     
  flag_trapping_math (0/0x1)                                                    
  flag_tree_loop_distribute_patterns (0x1/0)                                    
  flag_tree_loop_vectorize (0x1/0)                                              
  flag_tree_partial_pre (0x1/0)                                                 
  flag_tree_slp_vectorize (0x1/0)                                               
  flag_unsafe_math_optimizations (0x1/0)                                        
  flag_unswitch_loops (0x1/0)                                                   

so we fail because of errno-math difference.
The logic accepting/rejecitng inlines in can_inline_edge_p and I guess it is
the fact that we are affraid to inline safe math to unsafe.

I think certain combinations of flag will trigger ICE, such as one
enabling/disabling vector builtins. But I suppose we may want to bypass
majority of the checks for case we have always_inline w/o explicit optimization
attribute indeed, but only at early inlining time, probably not at LTO?
At LTO time we already did transformation that turn previously correct code
with target's optimization flags to be incorrect (i.e. -fstrict-aliasing blocks
some transformations we may do during early opts)

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