Fix recursion discovery in ipa-pure-const

Jan Hubicka
Thu Nov 11 13:40:37 GMT 2021

We make self recursive functions as looping of fear of endless recursion.
This is done correctly for local pure/const and for non-trivial SCCs in
callgraph, but for trivial SCCs we miss the flag.

I think it is bad decision since infinite recursion will run out of stack,
but changing it upsets some testcases and should be done independently.
So this patch is fixing current behaviour to be consistent.

Bootstrapped/regtested x86_64-linux, comitted.


2021-11-11  Jan Hubicka  <>

	* ipa-pure-const.c (propagate_pure_const): Self recursion is
	a side effects.

diff --git a/gcc/ipa-pure-const.c b/gcc/ipa-pure-const.c
index 505ed4f8a3b..64777cd2d91 100644
--- a/gcc/ipa-pure-const.c
+++ b/gcc/ipa-pure-const.c
@@ -1513,6 +1611,9 @@ propagate_pure_const (void)
 	      enum pure_const_state_e edge_state = IPA_CONST;
 	      bool edge_looping = false;
+	      if (e->recursive_p ())
+		looping = true;
 	      if (dump_file && (dump_flags & TDF_DETAILS))
 		  fprintf (dump_file, "    Call to %s",

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