In November 2009 I asked about these, and there was some good discussion following ( https://gcc.gnu.org/ml/gcc/2009-11/threads.html#00008 ); at one point it just makes sense to remove things that were already considered old back in a decade ago.
Committed. Gerald Index: index.html =================================================================== RCS file: /cvs/gcc/wwwdocs/htdocs/projects/index.html,v retrieving revision 1.70 diff -u -r1.70 index.html --- index.html 29 Jun 2014 11:31:33 -0000 1.70 +++ index.html 17 Apr 2015 22:58:42 -0000 @@ -31,7 +31,6 @@ <li><a href="#improve_the_installation_procedure">Improve the installation procedure</a></li> <li><a href="#simpler_porting">Simpler porting</a></li> <li><a href="#generalize_the_machine_model">Generalize the machine model</a></li> -<li><a href="#the_old_problems_file">The old PROBLEMS file</a></li> </ul> <p>Remember to <a href="../contributewhy.html">keep other developers @@ -104,34 +103,5 @@ used for scalars and another for large objects. The compiler does not now have a way to understand this.</p> -<h2><a name="the_old_problems_file">The old PROBLEMS file</a></h2> - -<p>The following used to be in a file <code>PROBLEMS</code> in the GCC - distribution. Probably much of it is no longer relevant as of GCC 3.0 -(the file hadn't changed since GCC 2.0), but some might be. Someone -should go through it, identifying what is and isn't relevant, adding -anything applicable to current GCC (and describing a bug) to our -bug-tracking system and/or updating this patch to remove such analysed -entries from the list.</p> - -<ol> - <li value="110">Possible special combination pattern: If the two - operands to a comparison die there and both come from insns that are - identical except for replacing one operand with the other, throw away - those insns. Ok if insns being discarded are known 1 to 1. An andl - #1 after a seq is 1 to 1, but how should compiler know that?</li> - - <li value="117">Any number of slow zero-extensions in one loop, that - have their clr insns moved out of the loop, can share one register if - their original life spans are disjoint. But it may be hard to be sure - of this since the life span data that regscan produces may be hard to - interpret validly or may be incorrect after cse.</li> - - <li value="118">In cse, when a bfext insn refers to a register, if the - field corresponds to a halfword or a byte and the register is - equivalent to a memory location, it would be possible to detect this - and replace it with a simple memory reference.</li> -</ol> - </body> </html>