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Re: Context sensitive type inheritance graph walking

On 2013.09.25 at 12:20 +0200, Jan Hubicka wrote:
> this is updated version of
> Bootstrapped/regtested x86_64-linux.  The patch is tested by ipa-devirt9
> testcase.  I have extra four, but I would like to first fix the case where the
> devirtualization happens in TODO of early_local_passes that is not dumped
> anywhere.  So I plan to post these incrementally once this code is hooked also
> into gimple folding.
> The patch results in 60% more devirtualizations on Firefox and 10% more
> speculative devirtualization.  I think main component missing now is code
> determining dynamic type from a call to constructor.  I have some prototype for
> this, too, I would like to discuss incrementally.  I am not 100% sure how much
> harder tracking of dynamic type changes becomes here.

Hi Honza,

I've tested your patch and it failed during the "profile generate" phase of an
LTO/PGO build of Firefox.


markus@x4 /tmp % cat test.ii
class A {
  virtual void m_fn1();
class B final : A {
  virtual void m_fn2() { m_fn1(); }
B::~B() {}

markus@x4 /tmp % g++ -c -std=c++11 -O2 -c test.ii
test.ii: In member function âvirtual void B::m_fn2()â:
test.ii:7:16: error: stmt (0x7f85504c3130) marked modified after optimization pass: 
   virtual void m_fn2() { m_fn1(); }
# .MEM_6 = VDEF <.MEM_2(D)>
A::m_fn1 (_5);
test.ii:7:16: internal compiler error: verify_ssa failed
0xc62364 verify_ssa(bool)
0xa305a1 execute_function_todo
0xa30d07 execute_todo
0xa32af9 execute_one_ipa_transform_pass
0xa32af9 execute_all_ipa_transforms()
0x7e3cc0 expand_function
0x7e5d96 expand_all_functions
0x7e5d96 compile()
0x7e6379 finalize_compilation_unit()
0x5f816e cp_write_global_declarations()
Please submit a full bug report,


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