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Is -O9 legitimate?
- From: "Lee Rhodes" <lee at rhoba dot com>
- To: <gcc-help at gcc dot gnu dot org>
- Date: Mon, 9 Jul 2007 11:25:21 -0700
- Subject: Is -O9 legitimate?
I am studying a Makefile where the author specified the execution of GCC as
follows:
gcc -O9 -fno-strict-aliasing ...
I could not find any reference to either -O9 or -fno-strict-aliasing in the
4.2.0 gcc.pdf manual. I did find -fstrict-aliasing, but most commands that
have a -fno- option are listed in the manual.
What effect does -O9 have?
Would -fno-strict-aliasing turn off strict-aliasing?
Is there a gcc switch that would issue warnings about either obsolete or
ignored command line switches?
Are there other undocumented switches?
Lee.