From 7f4e85a954d24cc30bf85f4040fcd204bd5e23fd Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Sat, 14 Dec 2024 11:28:25 +0100
Subject: [PATCH] gimple-fold: Fix the recent ifcombine optimization for
_BitInt [PR118023]
The BIT_FIELD_REF verifier has:
if (INTEGRAL_TYPE_P (TREE_TYPE (op))
&& !type_has_mode_precision_p (TREE_TYPE (op)))
{
error ("%qs of non-mode-precision operand", code_name);
return true;
}
check among other things, so one can't extract something out of say
_BitInt(63) or _BitInt(4096).
The new ifcombine optimization happily creates such BIT_FIELD_REFs
and ICEs during their verification.
The following patch fixes that by rejecting those in decode_field_reference.
2024-12-14 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/118023
* gimple-fold.cc (decode_field_reference): Return NULL_TREE if
inner has non-type_has_mode_precision_p integral type.
* gcc.dg/bitint-119.c: New test.
---
gcc/gimple-fold.cc | 4 +++-
gcc/testsuite/gcc.dg/bitint-119.c | 11 +++++++++++
2 files changed, 14 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/bitint-119.c
diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc
index e1b4b65dd662..6c11654a2c65 100644
--- a/gcc/gimple-fold.cc
+++ b/gcc/gimple-fold.cc
@@ -7643,7 +7643,9 @@ decode_field_reference (tree *pexp, HOST_WIDE_INT *pbitsize,
/* Reject out-of-bound accesses (PR79731). */
|| (! AGGREGATE_TYPE_P (TREE_TYPE (inner))
&& compare_tree_int (TYPE_SIZE (TREE_TYPE (inner)),
- bp + bs) < 0))
+ bp + bs) < 0)
+ || (INTEGRAL_TYPE_P (TREE_TYPE (inner))
+ && !type_has_mode_precision_p (TREE_TYPE (inner))))
return NULL_TREE;
*pbitsize = bs;
diff --git a/gcc/testsuite/gcc.dg/bitint-119.c b/gcc/testsuite/gcc.dg/bitint-119.c
new file mode 100644
index 000000000000..8283d50b3a68
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/bitint-119.c
@@ -0,0 +1,11 @@
+/* PR tree-optimization/118023 */
+/* { dg-do compile { target bitint } } */
+/* { dg-options "-O2" } */
+
+_BitInt(63) b;
+
+int
+foo (void)
+{
+ return !*(_Complex char *) &b;
+}
--
GitLab