On 4/30/24 12:22, Jakub Jelinek wrote:
On Tue, Apr 30, 2024 at 03:09:51PM -0400, Jason Merrill via Gcc wrote:
On Fri, Apr 26, 2024 at 5:44 AM Aldy Hernandez via Gcc <gcc@gcc.gnu.org> wrote:
In implementing prange (pointer ranges), I have found a 1.74% slowdown
in VRP, even without any code path actually using the code. I have
tracked this down to irange::get_bitmask() being compiled differently
with and without the bare bones patch. With the patch,
irange::get_bitmask() has a lot of code inlined into it, particularly
get_bitmask_from_range() and consequently the wide_int_storage code.
...
+static irange_bitmask
+get_bitmask_from_range (tree type,
+ const wide_int &min, const wide_int &max)
...
-irange_bitmask
-irange::get_bitmask_from_range () const
My guess is that this is the relevant change: the old function has
external linkage, and is therefore interposable, which inhibits
inlining. The new function has internal linkage, which allows
inlining.
Even when a function is exported, when not compiled with -fpic/-fPIC
if we know the function is defined in current TU, it can't be interposed,
Ah, I was misremembering the effect of the change. Rather, it's that if
we see that a function with internal linkage has only a single caller,
we try harder to inline it.
Jason
