Disable some bogus -Wmaybe-uninitialized warnings
gcc/ChangeLog: PR middle-end/97840 * ipa-modref.c (analyze_ssa_name_flags): Skip clobbers if inlining is done. * tree-ssa-uninit.c (maybe_warn_pass_by_reference): Make stmt gcall; skip const calls and unused arguments. (warn_uninitialized_vars): Update prototype. gcc/testsuite/ChangeLog: * g++.dg/warn/uninit-1.C: New test.
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@ -1333,7 +1333,14 @@ analyze_ssa_name_flags (tree name, vec<unsigned char> &known_flags, int depth)
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/* Handle *name = exp. */
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else if (assign
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&& memory_access_to (gimple_assign_lhs (assign), name))
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flags &= ~(EAF_UNUSED | EAF_NOCLOBBER);
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{
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/* In general we can not ignore clobbers because they are
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barriers for code motion, however after inlining it is safe to
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do because local optimization passes do not consider clobbers
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from other functions. Similar logic is in ipa-pure-const.c. */
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if (!cfun->after_inlining || !gimple_clobber_p (assign))
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flags &= ~(EAF_UNUSED | EAF_NOCLOBBER);
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}
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/* ASM statements etc. */
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else if (!assign)
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{
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@ -0,0 +1,29 @@
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/* { dg-do compile } */
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/* { dg-options "-O2 -Wmaybe-uninitialized" } */
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struct a {int a;};
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__attribute__ ((noinline))
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void
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nowarn (const struct a *ptr)
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{
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if (ptr)
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asm volatile ("");
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}
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void
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test()
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{
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struct a ptr;
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nowarn (&ptr);
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}
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__attribute__ ((noinline))
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int
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nowarn2 (const struct a *ptr, const struct a ptr2)
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{
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return ptr != 0 || ptr2.a;
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}
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int mem;
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int
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test2()
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{
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struct a ptr,ptr2={0};
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return nowarn2 (&ptr, ptr2);
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}
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@ -443,7 +443,7 @@ maybe_warn_operand (ao_ref &ref, gimple *stmt, tree lhs, tree rhs,
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access implying read access to those objects. */
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static void
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maybe_warn_pass_by_reference (gimple *stmt, wlimits &wlims)
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maybe_warn_pass_by_reference (gcall *stmt, wlimits &wlims)
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{
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if (!wlims.wmaybe_uninit)
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return;
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@ -457,6 +457,10 @@ maybe_warn_pass_by_reference (gimple *stmt, wlimits &wlims)
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if (!fntype)
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return;
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/* Const function do not read their arguments. */
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if (gimple_call_flags (stmt) & ECF_CONST)
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return;
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const built_in_function fncode
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= (fndecl && gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)
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? DECL_FUNCTION_CODE (fndecl) : (built_in_function)BUILT_IN_LAST);
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@ -523,6 +527,10 @@ maybe_warn_pass_by_reference (gimple *stmt, wlimits &wlims)
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(but not definitive) read access. */
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wlims.always_executed = false;
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/* Ignore args we are not going to read from. */
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if (gimple_call_arg_flags (stmt, argno - 1) & EAF_UNUSED)
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continue;
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tree arg = gimple_call_arg (stmt, argno - 1);
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ao_ref ref;
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@ -639,8 +647,8 @@ warn_uninitialized_vars (bool wmaybe_uninit)
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if (gimple_vdef (stmt))
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wlims.vdef_cnt++;
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if (is_gimple_call (stmt))
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maybe_warn_pass_by_reference (stmt, wlims);
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if (gcall *call = dyn_cast <gcall *> (stmt))
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maybe_warn_pass_by_reference (call, wlims);
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else if (gimple_assign_load_p (stmt)
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&& gimple_has_location (stmt))
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{
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