https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109462
https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=24af552876eff707f75d30d3f0f0e7a5d62dd857

From 24af552876eff707f75d30d3f0f0e7a5d62dd857 Mon Sep 17 00:00:00 2001
From: Andrew MacLeod <amacleod@redhat.com>
Date: Tue, 11 Apr 2023 17:29:03 -0400
Subject: [PATCH] Don't use ANY PHI equivalences in range-on-entry.

PR 108139 dissallows PHI equivalencies in the on-entry calculator, but
it was only checking if the equivlaence was a PHI.  In this case, NAME
itself is a PHI with an equivlaence caused by an undefined value, so we
also need to check that case.  Unfortunately this un-fixes 101912.

	PR tree-optimization/109462
	gcc/
	* gimple-range-cache.cc (ranger_cache::fill_block_cache): Don't
	check for equivalences if NAME is a phi node.

	gcc/testsuite/
	* gcc.dg/uninit-pr101912.c: XFAIL the warning.
--- a/gcc/gimple-range-cache.cc
+++ b/gcc/gimple-range-cache.cc
@@ -1218,7 +1218,9 @@ ranger_cache::fill_block_cache (tree name, basic_block bb, basic_block def_bb)
 	  fprintf (dump_file, "\n");
 	}
       // See if any equivalences can refine it.
-      if (m_oracle)
+      // PR 109462, like 108139 below, a one way equivalence introduced
+      // by a PHI node can also be through the definition side.  Disallow it.
+      if (m_oracle && !is_a<gphi *> (SSA_NAME_DEF_STMT (name)))
 	{
 	  tree equiv_name;
 	  relation_kind rel;
--- a/gcc/testsuite/gcc.dg/uninit-pr101912.c
+++ b/gcc/testsuite/gcc.dg/uninit-pr101912.c
@@ -11,7 +11,7 @@ tzloadbody (void)
   for (int i = 0; i < n; i++)
     {
       int corr = getint ();
-      if (corr < 1 || (corr == 1 && !(leapcnt == 0 || (prevcorr < corr ? corr == prevcorr + 1 : (corr == prevcorr || corr == prevcorr - 1))))) /* { dg-bogus "uninitialized" } */
+      if (corr < 1 || (corr == 1 && !(leapcnt == 0 || (prevcorr < corr ? corr == prevcorr + 1 : (corr == prevcorr || corr == prevcorr - 1))))) /* { dg-bogus "uninitialized" "pr101912" { xfail *-*-* } } */
 	return -1;
 
       prevcorr = corr;
-- 
2.31.1