Fix handling of ICF_NOVOPS in ipa-modref

As shown in somewhat convoluted testcase, ipa-modref is mistreating
ECF_NOVOPS as "having no side effects".  This come from time when
modref cared only about memory accesses and thus it was possible to
shortcut on it.

This patch removes (hopefully) all those bad shortcuts.
Bootstrapped/regtested x86_64-linux, comitted.

gcc/ChangeLog:

	PR ipa/109985

	* ipa-modref.cc (modref_summary::useful_p): Fix handling of ECF_NOVOPS.
	(modref_access_analysis::process_fnspec): Likevise.
	(modref_access_analysis::analyze_call): Likevise.
	(propagate_unknown_call): Likevise.
	(modref_propagate_in_scc): Likevise.
	(modref_propagate_flags_in_scc): Likewise.
	(ipa_merge_modref_summary_after_inlining): Likewise.

1 files changed, 21 insertions, 15 deletions

diff --git a/gcc/ipa-modref.cc b/gcc/ipa-modref.cc
index 53a2e35..f6a758b 100644
--- a/gcc/ipa-modref.cc
+++ b/gcc/ipa-modref.cc
@@ -334,7 +334,7 @@ modref_summary::useful_p (int ecf_flags, bool check_flags)
   if (check_flags
       && remove_useless_eaf_flags (static_chain_flags, ecf_flags, false))
     return true;
-  if (ecf_flags & (ECF_CONST | ECF_NOVOPS))
+  if (ecf_flags & ECF_CONST)
     return ((!side_effects || !nondeterministic)
 	    && (ecf_flags & ECF_LOOPING_CONST_OR_PURE));
   if (loads && !loads->every_base)
@@ -1263,7 +1263,7 @@ modref_access_analysis::merge_call_side_effects
   int flags = gimple_call_flags (call);
 
   /* Nothing to do for non-looping cont functions.  */
-  if ((flags & (ECF_CONST | ECF_NOVOPS))
+  if ((flags & ECF_CONST)
       && !(flags & ECF_LOOPING_CONST_OR_PURE))
     return false;
 
@@ -1276,7 +1276,7 @@ modref_access_analysis::merge_call_side_effects
   /* 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))
+  if (!(flags & (ECF_CONST | ECF_PURE))
       || (flags & ECF_LOOPING_CONST_OR_PURE))
     {
       if (!m_summary->side_effects && callee_summary->side_effects)
@@ -1465,7 +1465,7 @@ modref_access_analysis::process_fnspec (gcall *call)
 
   /* 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))
+  if (!(flags & (ECF_CONST | ECF_PURE))
       || (flags & ECF_LOOPING_CONST_OR_PURE)
       || (cfun->can_throw_non_call_exceptions
 	  && stmt_could_throw_p (cfun, call)))
@@ -1604,12 +1604,12 @@ modref_access_analysis::analyze_call (gcall *stmt)
       print_gimple_stmt (dump_file, stmt, 0);
     }
 
-  if ((flags & (ECF_CONST | ECF_NOVOPS))
+  if ((flags & ECF_CONST)
       && !(flags & ECF_LOOPING_CONST_OR_PURE))
     {
       if (dump_file)
 	fprintf (dump_file,
-		 " - ECF_CONST | ECF_NOVOPS, ignoring all stores and all loads "
+		 " - ECF_CONST, ignoring all stores and all loads "
 		 "except for args.\n");
       return;
     }
@@ -1624,7 +1624,13 @@ modref_access_analysis::analyze_call (gcall *stmt)
       if (dump_file)
 	fprintf (dump_file, gimple_call_internal_p (stmt)
 		 ? " - Internal call" : " - Indirect call.\n");
-      process_fnspec (stmt);
+      if (flags & ECF_NOVOPS)
+        {
+	  set_side_effects ();
+	  set_nondeterministic ();
+        }
+      else
+	process_fnspec (stmt);
       return;
     }
   /* We only need to handle internal calls in IPA mode.  */
@@ -4568,7 +4574,7 @@ propagate_unknown_call (cgraph_node *node,
       return changed;
     }
 
-  if (!(ecf_flags & (ECF_CONST | ECF_NOVOPS | ECF_PURE))
+  if (!(ecf_flags & (ECF_CONST | ECF_PURE))
       || (ecf_flags & ECF_LOOPING_CONST_OR_PURE)
       || nontrivial_scc)
     {
@@ -4782,7 +4788,7 @@ modref_propagate_in_scc (cgraph_node *component_node)
 	      struct cgraph_node *callee;
 
 	      if (!callee_edge->inline_failed
-		 || ((flags & (ECF_CONST | ECF_NOVOPS))
+		 || ((flags & ECF_CONST)
 		     && !(flags & ECF_LOOPING_CONST_OR_PURE)))
 		continue;
 
@@ -5205,8 +5211,8 @@ modref_propagate_flags_in_scc (cgraph_node *component_node)
 	    {
 	      escape_summary *sum = escape_summaries->get (e);
 
-	      if (!sum || (e->indirect_info->ecf_flags
-			   & (ECF_CONST | ECF_NOVOPS)))
+	      if (!sum || ((e->indirect_info->ecf_flags & ECF_CONST)
+		  && !(e->indirect_info->ecf_flags & ECF_LOOPING_CONST_OR_PURE)))
 		continue;
 
 	      changed |= modref_merge_call_site_flags
@@ -5231,8 +5237,8 @@ modref_propagate_flags_in_scc (cgraph_node *component_node)
 	      modref_summary_lto *callee_summary_lto = NULL;
 	      struct cgraph_node *callee;
 
-	      if (ecf_flags & (ECF_CONST | ECF_NOVOPS)
-		  || !callee_edge->inline_failed)
+	      if ((ecf_flags & ECF_CONST)
+		  && !(ecf_flags & ECF_LOOPING_CONST_OR_PURE))
 		continue;
 
 	      /* Get the callee and its summary.  */
@@ -5330,7 +5336,7 @@ ipa_merge_modref_summary_after_inlining (cgraph_edge *edge)
 
   if (!callee_info && to_info)
     {
-      if (!(flags & (ECF_CONST | ECF_NOVOPS)))
+      if (!(flags & (ECF_CONST | ECF_PURE | ECF_NOVOPS)))
 	to_info->loads->collapse ();
       if (!ignore_stores)
 	to_info->stores->collapse ();
@@ -5345,7 +5351,7 @@ ipa_merge_modref_summary_after_inlining (cgraph_edge *edge)
   /* 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))
+  if (!(flags & (ECF_CONST | ECF_PURE))
       || (flags & ECF_LOOPING_CONST_OR_PURE))
     {
       if (to_info)