Clarify that -O2 sets -fstrict-aliasing

From-SVN: r51097
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Michael Meissner 2002-03-20 22:56:33 +00:00 committed by Michael Meissner
parent 86d8c251a1
commit 852b81bbe0
2 changed files with 13 additions and 4 deletions

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@ -1,3 +1,8 @@
2002-03-20 Michael Meissner <meissner@redhat.com>
* doc/invoke.texi (Optimize Options): Document that -O2 sets
-fstrict-aliasing.
2002-03-20 Bob Wilson <bob.wilson@acm.org> 2002-03-20 Bob Wilson <bob.wilson@acm.org>
* config/xtensa/xtensa.h (ASM_OUTPUT_POOL_PROLOGUE): Emit a * config/xtensa/xtensa.h (ASM_OUTPUT_POOL_PROLOGUE): Emit a

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@ -3170,10 +3170,11 @@ perform loop unrolling or function inlining when you specify @option{-O2}.
As compared to @option{-O}, this option increases both compilation time As compared to @option{-O}, this option increases both compilation time
and the performance of the generated code. and the performance of the generated code.
@option{-O2} turns on all optional optimizations except for loop unrolling, @option{-O2} turns on all optional optimizations except for loop
function inlining, and register renaming. It also turns on the unrolling, function inlining, and register renaming. It also turns on
@option{-fforce-mem} option on all machines and frame pointer elimination the @option{-fforce-mem} and @option{-fstrict-aliasing} option on all
on machines where doing so does not interfere with debugging. machines and frame pointer elimination on machines where doing so does
not interfere with debugging.
Please note the warning under @option{-fgcse} about Please note the warning under @option{-fgcse} about
invoking @option{-O2} on programs that use computed gotos. invoking @option{-O2} on programs that use computed gotos.
@ -3716,6 +3717,9 @@ node, an alias set for the node. Nodes in different alias sets are not
allowed to alias. For an example, see the C front-end function allowed to alias. For an example, see the C front-end function
@code{c_get_alias_set}. @code{c_get_alias_set}.
For all machines, optimization level 2 and higher enables this flag by
default.
@item -falign-functions @item -falign-functions
@itemx -falign-functions=@var{n} @itemx -falign-functions=@var{n}
@opindex falign-functions @opindex falign-functions