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.
Bootstrapped and tested on x86_64-unknown-linux-gnu, will push
later.
Martin - do you remember which case was supposed to be allowed
with offset < model->offset?
Thanks,
Richard.
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.
---
gcc/testsuite/gcc.dg/torture/pr111807.c | 12 ++++++++++++
gcc/tree-sra.cc | 2 +-
2 files changed, 13 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr111807.c
diff --git a/gcc/testsuite/gcc.dg/torture/pr111807.c
b/gcc/testsuite/gcc.dg/torture/pr111807.c
new file mode 100644
index 00000000000..09fbdcfb667
--- /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 24d0c20da6a..f8dff8b27d7 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)))
--
2.35.3
