[C++ PATCH] Fix 14179 - compile-time

["Giovanni Bajo" <giovannibajo at libero dot it>]

Hello,

c++/14179 is a PR about having an array of 8 millions of elements with
initializers for all of them. We used to handle this pretty fast with GCC 2.95
(as we were expanding on the fly), but right now this is both a compile-time
and memory hog.

This patch addresses some compile-time issues, by tweaking
cp_parser_initializer_clause, so that it's super fast for simple literals used
in initializers. This allows my rather slow computer to compile an array with
half million of elements in 0m32 instead of 0m50, which is a 40% improvement.
In projection, I'm theoretically able to compile the full testcase in "only" 8
minutes (this is a checking compiler, though); GCC 2.95 can do it in 1m30.

Tested on i686-pc-linux-gnu, no new regressions. OK for mainline? OK for 3.4?

Giovanni Bajo


cp/
        PR c++/14179
        * parser.c (cp_parser_initializer): Speed up parsing of simple
        literals as initializers.

Attachment: patch-pr14179-1.txt
Description: Text document