From: Richard Biener <rguenther@suse.de>
Date: Mon, 11 Aug 2025 12:43:58 +0000 (+0200)
Subject: Restrict aggregate copy VN generalization
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=6d9c1aad2c46092ac0e5adcaad2ea5af57fad180;p=thirdparty%2Fgcc.git

Restrict aggregate copy VN generalization

The following avoids ending up with a MEM_REF as component to apply.

	* tree-ssa-sccvn.cc (vn_reference_lookup_3): When we fail to
	match up the two base MEM_REFs, fail.
---

diff --git a/gcc/tree-ssa-sccvn.cc b/gcc/tree-ssa-sccvn.cc
index 61d794d8407..cdd7c0542ad 100644
--- a/gcc/tree-ssa-sccvn.cc
+++ b/gcc/tree-ssa-sccvn.cc
@@ -3631,7 +3631,12 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
 	    {
 	      extra_off = vr->operands[i].off - lhs_ops[j].off;
 	      i--, j--;
+	      found = true;
 	    }
+	  /* If we did find a match we'd eventually append a MEM_REF
+	     as component.  Don't.  */
+	  if (!found)
+	    return (void *)-1;
 	}
       else
 	return (void *)-1;