ipa/103989 - tame IPA optimizations at -Og

With -Og we are not prepared to do cleanup after IPA optimizations
and dead code exposed by those confuses late diagnostic passes.
This is a first patch removing unwanted IPA optimizations, namely
both late modref and pure-const analysis.

2022-01-18  Richard Biener  <rguenther@suse.de>

	PR ipa/103989
	* passes.def (pass_all_optimizations_g): Remove pass_modref
	and pass_local_pure_const.

diff --git a/gcc/passes.def b/gcc/passes.def
index 7880842..3e75de4 100644 (file)
--- a/gcc/passes.def
+++ b/gcc/passes.def
@@ -372,6 +372,9 @@ along with GCC; see the file COPYING3.  If not see
   POP_INSERT_PASSES ()
   NEXT_PASS (pass_all_optimizations_g);
   PUSH_INSERT_PASSES_WITHIN (pass_all_optimizations_g)
+      /* The idea is that with -Og we do not perform any IPA optimization
+        so post-IPA work should be restricted to semantically required
+        passes and all optimization work is done early.  */
       NEXT_PASS (pass_remove_cgraph_callee_edges);
       NEXT_PASS (pass_strip_predict_hints, false /* early_p */);
       /* Lower remaining pieces of GIMPLE.  */
@@ -399,8 +402,6 @@ along with GCC; see the file COPYING3.  If not see
          number of false positives from it.  */
       NEXT_PASS (pass_split_crit_edges);
       NEXT_PASS (pass_late_warn_uninitialized);
-      NEXT_PASS (pass_local_pure_const);
-      NEXT_PASS (pass_modref);
       /* uncprop replaces constants by SSA names.  This makes analysis harder
         and thus it should be run last.  */
       NEXT_PASS (pass_uncprop);