Vendored wiredtiger rand.c fails to compile without -fno-strict-aliasing

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    • Type: Bug
    • Resolution: Done
    • Priority: Major - P3
    • 3.1.7
    • Affects Version/s: None
    • Component/s: Build, Internal Code, WiredTiger
    • None
    • Environment:
      Ubuntu 15.04, GCC 4.9.2
    • Fully Compatible
    • ALL
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      Remove -fno-strict-aliasing from the top level SConstruct and build with a modern GCC.

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      Remove -fno-strict-aliasing from the top level SConstruct and build with a modern GCC.
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      If the -fno-strict-aliasing flag is removed from the top level SConstruct, the vendored WiredTiger sources in src/third_party/wiredtiger do not compile. In particular, the rand.c file generates strict aliasing errors:

      src/third_party/wiredtiger/src/support/rand.c: In function '__wt_random_init':
src/third_party/wiredtiger/src/support/rand.c:57:2: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  M_W(rnd) = 521288629;
  ^
src/third_party/wiredtiger/src/support/rand.c: In function '__wt_random':
src/third_party/wiredtiger/src/support/rand.c:78:2: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  w = M_W(rnd);
  ^
src/third_party/wiredtiger/src/support/rand.c:91:2: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  M_W(rnd) = w = 18000 * (w & 65535) + (w >> 16);
  ^
cc1: all warnings being treated as errors

            Assignee:
            Unassigned
            Reporter:
            Andrew Morrow (Inactive)
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              Created:
              Updated:
              Resolved: