[Bug tree-optimization/39207] New: [4.4 Regression] Strict aliasing warnings in libstdc++ headers

[jakub at gcc dot gnu dot org]

#include <string>
#include <map>

const std::string &usage ();

void
foo ()
{ 
  std::map < std::string, int >best_scores;
  const std::map < std::string, int >::const_iterator current_best =
best_scores.find (usage ());
  if (0 < current_best->second) best_scores[usage ()] = 0;
}

yields:
LC_ALL=C g++ -S -O2 -Wall ai.C
ai.C: In function 'void foo()':
ai.C:11: warning: dereferencing pointer '<anonymous>' does break
strict-aliasing rules
/usr/lib/gcc/i386-redhat-linux/4.4.0/../../../../include/c++/4.4.0/bits/stl_tree.h:259:
note: initialized from here

I'll attach another testcase which doesn't include any headers and triggers 3
warnings.


-- 
           Summary: [4.4 Regression] Strict aliasing warnings in libstdc++
                    headers
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jakub at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39207