From: Richard Biener <rguenther@suse.de>
Date: Mon, 16 Oct 2023 10:54:28 +0000 (+0200)
Subject: tree-optimization/111807 - ICE in verify_sra_access_forest
X-Git-Tag: basepoints/gcc-15~5462
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3aaf704bca3e;p=thirdparty%2Fgcc.git

tree-optimization/111807 - ICE in verify_sra_access_forest

The following addresses build_reconstructed_reference failing to
build references with a different offset than the models and thus
the caller conditional being off.  This manifests when attempting
to build a ref with offset 160 from the model BIT_FIELD_REF <l_4827[9], 8, 0>
onto the same base l_4827 but the models offset being 288.  This
cannot work for any kind of ref I can think of, not just with
BIT_FIELD_REFs.

	PR tree-optimization/111807
	* tree-sra.cc (build_ref_for_model): Only call
	build_reconstructed_reference when the offsets are the same.

	* gcc.dg/torture/pr111807.c: New testcase.
---

diff --git a/gcc/testsuite/gcc.dg/torture/pr111807.c b/gcc/testsuite/gcc.dg/torture/pr111807.c
new file mode 100644
index 000000000000..09fbdcfb667a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr111807.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+
+static struct A {
+  int x : 4;
+} a;
+static int b;
+int main()
+{
+  struct A t[2];
+  t[0] = b ? t[1] : a;
+  return (b ? t[1].x : 0) && 1;
+}
diff --git a/gcc/tree-sra.cc b/gcc/tree-sra.cc
index 24d0c20da6ae..f8dff8b27d76 100644
--- a/gcc/tree-sra.cc
+++ b/gcc/tree-sra.cc
@@ -1751,7 +1751,7 @@ build_ref_for_model (location_t loc, tree base, HOST_WIDE_INT offset,
 	  && !TREE_THIS_VOLATILE (base)
 	  && (TYPE_ADDR_SPACE (TREE_TYPE (base))
 	      == TYPE_ADDR_SPACE (TREE_TYPE (model->expr)))
-	  && offset <= model->offset
+	  && offset == model->offset
 	  /* build_reconstructed_reference can still fail if we have already
 	     massaged BASE because of another type incompatibility.  */
 	  && (res = build_reconstructed_reference (loc, base, model)))