Re: [PATCH] pragma: Update target option node when optimization changes [PR103515]

[Jeff Law <jeffreyalaw@gmail.com>]

On 12/6/2021 7:15 PM, Kewen.Lin via Gcc-patches wrote:
> Hi,
>
> For a function with optimize pragma, it's possible that the target
> options change as optimization options change.  Now we create one
> optimization option node when parsing pragma optimize, but don't
> create target option node for possible target option changes.  It
> makes later processing not detect the target options have actually
> changed and doesn't update the target options accordingly.
>
> This patch is to check whether target options have changed when
> creating one optimization option node for pragma optimize, and
> make one target option node if needed.  The associated test case
> shows the difference.  Without this patch, the function foo1 will
> perform unrolling which is unexpected.  The reason is that flag
> unroll_only_small_loops isn't correctly set for it.  The value
> is updated after parsing function foo2, but doesn't get restored
> later since both decls don't have DECL_FUNCTION_SPECIFIC_TARGET
> set and the hook think we don't need to switch.  With this patch,
> there is no unrolling for foo1, which is also consistent with the
> behavior by replacing pragma by attribute whether w/ and w/o this
> patch.
>
> Bootstrapped and regtested on x86_64-redhat-linux, aarch64-linux-gnu
> and powerpc64{,le}-linux-gnu.
>
> Is it ok for trunk?
>
> BR,
> Kewen
> ---
> gcc/ChangeLog:
>
> 	PR target/103515
> 	* attribs.c (decl_attributes): Check if target options change and
> 	create one node if so.
>
> gcc/testsuite/ChangeLog:
>
> 	PR target/103515
> 	* gcc.target/powerpc/pr103515.c: New test.
OK
jeff