Re: LTO Test Case Help

[Michael Ploujnikov <michael dot ploujnikov at oracle dot com>]

On 2018-12-05 2:38 p.m., Michael Ploujnikov wrote:
> Hi,
> 
> I'm trying to write a testcase to reproduce duplicate clone symbols
> such as in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88297 I
> started with a testcase that is known to have constprop clones and
> split it into two object files:
> 
> 
> bash-4.2# cat /gcc/src/gcc/testsuite/gcc.dg/lto/independent-cloneids-lto_0.c 
> /* { dg-require-effective-target lto } */
> /* { dg-lto-options {{-O3 -fipa-cp -fipa-cp-clone}}  } */
> /* { dg-lto-do run } */
> 
> #include <stdio.h>
> 
> extern int foo (int arg);
> extern int bar (int arg);
> int __attribute__ ((noinline))
> foo (int arg)
> {
>   return 7 * arg;
> }
> 
> int __attribute__ ((noinline))
> bar (int arg)
> {
>   return arg * arg;
> }
> 
> int main (void)
> {
>   printf("%d\n", bar (3));
>   printf("%d\n", bar (4));
>   printf("%d\n", foo (5));
>   printf("%d\n", foo (6));
>   return 0;
> }
> 
> bash-4.2# cat /gcc/src/gcc/testsuite/gcc.dg/lto/independent-cloneids-lto_1.c 
> int __attribute__ ((noinline))
> foo (int arg)
> {
>   return 7 * arg;
> }
> 
> int __attribute__ ((noinline))
> bar (int arg)
> {
>   return arg * arg;
> }
> 
> but now decide_whether_version_node does not call decide_about_value
> and I don't know enough about ipa/lattices to figure out what's
> missing. Any help would be appreciated.
> 
> 
> - Michael
> 

If I print out the lattices in decide_whether_version_node right
before the call to gather_context_independent_values (and some more
info within the loop and after) I see:

debug: decide_whether_version_node - node: bar count is 1

Lattices:
  Node: main/13:
  Node: bar/12:
    param [0]: BOTTOM
         ctxs: BOTTOM
         Bits unusable (BOTTOM)
         VARYING
        AGGS BOTTOM
  Node: foo/11:
    param [0]: BOTTOM
         ctxs: BOTTOM
         Bits unusable (BOTTOM)
         VARYING
        AGGS BOTTOM
debug: decide_whether_version_node - !lat->bottom: 0
debug: decide_whether_version_node - !plats->aggs_bottom: 0
debug: decide_whether_version_node - node : bar info->do_clone_for_all_contexts: 0
debug: decide_whether_version_node - node: foo count is 1

Lattices:
  Node: main/13:
  Node: bar/12:
    param [0]: BOTTOM
         ctxs: BOTTOM
         Bits unusable (BOTTOM)
         VARYING
        AGGS BOTTOM
  Node: foo/11:
    param [0]: BOTTOM
         ctxs: BOTTOM
         Bits unusable (BOTTOM)
         VARYING
        AGGS BOTTOM
debug: decide_whether_version_node - !lat->bottom: 0
debug: decide_whether_version_node - !plats->aggs_bottom: 0
debug: decide_whether_version_node - node : foo info->do_clone_for_all_contexts: 0

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