[gcc r12-8069] Propagate nondeterministic and side_effects flags in modref summary after inlining

[gcc r12-8069] Propagate nondeterministic and side_effects flags in modref summary after inlining

[Jan Hubicka]

https://gcc.gnu.org/g:aabb9a261ef060cf24fd626713f1d7d9df81aa57

commit r12-8069-gaabb9a261ef060cf24fd626713f1d7d9df81aa57
Author: Jan Hubicka <jh@suse.cz>
Date:   Sat Apr 9 21:05:52 2022 +0200

    Propagate nondeterministic and side_effects flags in modref summary after inlining
    
    gcc/ChangeLog:
    
    2022-04-09  Jan Hubicka  <hubicka@ucw.cz>
    
            * ipa-modref.cc (ipa_merge_modref_summary_after_inlining): Propagate
            nondeterministic and side_effects flags.
    
    gcc/testsuite/ChangeLog:
    
    2022-04-09  Jan Hubicka  <hubicka@ucw.cz>
    
            * gcc.dg/ipa/pr105160.c: New test.

Diff:
---
 gcc/ipa-modref.cc                   | 23 +++++++++++
 gcc/testsuite/gcc.dg/ipa/pr105160.c | 77 +++++++++++++++++++++++++++++++++++++
 2 files changed, 100 insertions(+)

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"  } } */