Revert "workarounds for gcc optimizer misbuilds" [ci skip]

This reverts commit 51491b3.

src/c4/yml/parse_engine.def.hpp

@@ -102,14 +102,6 @@ inline bool _is_doc_token(csubstr s) noexcept
     // The current version does not suffer this problem, but it may
     // appear again.
     //
-    //
-    // UPDATE. The problem appeared again in gcc12 and gcc13 with -Os
-    // (but not any other optimization level, nor any other compiler
-    // or version), because the assignment to s is being hoisted out
-    // of the loop which calls this function. Then the length doesn't
-    // enter the s.len >= 3 when it should. Adding a
-    // C4_DONT_OPTIMIZE(var) makes the problem go away.
-    //
     if(s.len >= 3)
     {
         switch(s.str[0])
@@ -1947,9 +1939,6 @@ typename ParseEngine<EventHandler>::ScannedScalar ParseEngine<EventHandler>::_sc
     while( ! _finished_file())
     {
         const csubstr line = m_evt_handler->m_curr->line_contents.rem;
-        #if defined(__GNUC__) && __GNUC__ == 11
-        C4_DONT_OPTIMIZE(line); // prevent erroneous hoist of the assignment out of the loop
-        #endif
         bool line_is_blank = true;
         _c4dbgpf("scanning double quoted scalar @ line[{}]:  line='{}'", m_evt_handler->m_curr->pos.line, line);
         for(size_t i = 0; i < line.len; ++i)
@@ -2099,9 +2088,6 @@ void ParseEngine<EventHandler>::_scan_block(ScannedBlock *C4_RESTRICT sb, size_t
     {
         // peek next line, but do not advance immediately
         lc.reset_with_next_line(m_buf, m_evt_handler->m_curr->pos.offset);
-        #if defined(__GNUC__) && (__GNUC__ == 12 || __GNUC__ == 13)
-        C4_DONT_OPTIMIZE(lc.rem);
-        #endif
         _c4dbgpf("blck: peeking at [{}]~~~{}~~~", lc.stripped.len, lc.stripped);
         // evaluate termination conditions
         if(indentation != npos)

src/c4/yml/parser_state.hpp

@@ -66,9 +66,6 @@ struct LineContents
             ++e;
         RYML_ASSERT(e >= offset);
         const substr stripped_ = buf.range(offset, e);
-        #if defined(__GNUC__) && __GNUC__ == 11
-        C4_DONT_OPTIMIZE(stripped_);
-        #endif
         // advance pos to include the first line ending
         if(e < buf.len && buf.str[e] == '\r')
             ++e;