On Thu, Apr 7, 2022 at 1:20 PM Jan Hubicka via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Hi,
> this patch fixes ipa-modref propagation of pure/const functions. When we
> inline
> function, the modref summary is updated to represent the function after
> inlining and there we need to propagate nondeterministic and side-effects
> flag.
>
> Bootstrapped/regtested x86_64-linux, will commit it shortly.
I noticed we have ->writes_errno in the summary which we do not handle
in this function either? That's also missing on the GCC 11 branch
(where I just picked r12-2851-g9851a1631f2915 and
r12-5538-ga70faf6e4df748, both still in testing).
Richard.
> Honza
>
> gcc/ChangeLog:
>
> 2022-04-07 Jan Hubicka <hubi...@ucw.cz>
>
> PR ipa/105160
> * ipa-modref.cc (ipa_merge_modref_summary_after_inlining):
>
> gcc/testsuite/ChangeLog:
>
> 2022-04-07 Jan Hubicka <hubi...@ucw.cz>
>
> PR ipa/105160
> * gcc.dg/ipa/pr105160.c: New test.
>
> diff --git a/gcc/ipa-modref.cc b/gcc/ipa-modref.cc
> index acfd7d80ff8..556816ab429 100644
> --- a/gcc/ipa-modref.cc
> +++ b/gcc/ipa-modref.cc
> @@ -5281,6 +5281,29 @@ ipa_merge_modref_summary_after_inlining (cgraph_edge
> *edge)
> if (!ignore_stores)
> to_info_lto->stores->collapse ();
> }
> + /* Merge side effects and non-determinism.
> + PURE/CONST flags makes functions deterministic and if there is
> + no LOOPING_CONST_OR_PURE they also have no side effects. */
> + if (!(flags & (ECF_CONST | ECF_NOVOPS | ECF_PURE))
> + || (flags & ECF_LOOPING_CONST_OR_PURE))
> + {
> + if (to_info)
> + {
> + if (!callee_info || callee_info->side_effects)
> + to_info->side_effects = true;
> + if ((!callee_info || callee_info->nondeterministic)
> + && !ignore_nondeterminism_p (edge->caller->decl, flags))
> + to_info->nondeterministic = true;
> + }
> + if (to_info_lto)
> + {
> + if (!callee_info_lto || callee_info_lto->side_effects)
> + to_info_lto->side_effects = true;
> + if ((!callee_info_lto || callee_info_lto->nondeterministic)
> + && !ignore_nondeterminism_p (edge->caller->decl, flags))
> + to_info_lto->nondeterministic = true;
> + }
> + }
> if (callee_info || callee_info_lto)
> {
> auto_vec <modref_parm_map, 32> parm_map;
> diff --git a/gcc/testsuite/gcc.dg/ipa/pr105160.c
> b/gcc/testsuite/gcc.dg/ipa/pr105160.c
> new file mode 100644
> index 00000000000..ea80545b102
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/ipa/pr105160.c
> @@ -0,0 +1,77 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O -fdump-ipa-modref" } */
> +#define sysreg_read(regname) \
> +({ \
> + unsigned long __sr_val; \
> + asm volatile(""); \
> + \
> + __sr_val; \
> +})
> +
> +#define sysreg_write(regname, __sw_val) \
> +do { \
> + asm volatile(""); \
> +} while (0)
> +
> +#define isb() \
> +do { \
> + asm volatile( \
> + "isb" \
> + : \
> + : \
> + : "memory"); \
> +} while (0)
> +
> +static unsigned long sctlr_read(void)
> +{
> + return sysreg_read(sctlr_el1);
> +}
> +
> +static void sctlr_write(unsigned long val)
> +{
> + sysreg_write(sctlr_el1, val);
> +}
> +
> +static void sctlr_rmw(void)
> +{
> + unsigned long val;
> +
> + val = sctlr_read();
> + val |= 1UL << 7;
> + sctlr_write(val);
> +}
> +
> +void sctlr_read_multiple(void)
> +{
> + sctlr_read();
> + sctlr_read();
> + sctlr_read();
> + sctlr_read();
> +}
> +
> +void sctlr_write_multiple(void)
> +{
> + sctlr_write(0);
> + sctlr_write(0);
> + sctlr_write(0);
> + sctlr_write(0);
> + sctlr_write(0);
> +}
> +
> +void sctlr_rmw_multiple(void)
> +{
> + sctlr_rmw();
> + sctlr_rmw();
> + sctlr_rmw();
> + sctlr_rmw();
> +}
> +
> +void function(void)
> +{
> + sctlr_read_multiple();
> + sctlr_write_multiple();
> + sctlr_rmw_multiple();
> +
> + isb();
> +}
> +/* { dg-final { scan-ipa-dump-not "Function found to be const" "modref" } }
> */
