[PATCH] testsuite: analyzer: expect alignment warning with -fshort-enums

[Alexandre Oliva <oliva@adacore.com>]

On targets that have -fshort-enums enabled by default, the type casts
in the pr108251 analyzer tests warn that the byte-aligned enums may
not be sufficiently aligned to be a struct connection *.  The function
can't know better, the warning is reasonable, the code doesn't
expected enums to be shorter and less aligned than the struct.

Rather than use -fno-short-enums, I decided to embrace the warning on
targets that have short_enums enabled by default.

However, C++ doesn't issue the warning, because even with
-fshort-enums, enumeration types are not TYPE_PACKED, and the
expression is not sufficiently simplified by the C++ front-end for
check_and_warn_address_or_pointer_of_packed_member to identify the
insufficiently aligned pointer.  So don't expect the warning there.

(I've got followup patches in testing to get the same warnings in C++)

Regstrapped on x86_64-linux-gnu, also tested on arm-eabi with default
cpu on trunk, and with tms570 on gcc-13.  Ok to install?


for  gcc/testsuite/ChangeLog

	* c-c++-common/analyzer/null-deref-pr108251-smp_fetch_ssl_fc_has_early-O2.c:
	Expect "unaligned pointer value" warning on short_enums
	targets, but not in c++.
	* c-c++-common/analyzer/null-deref-pr108251-smp_fetch_ssl_fc_has_early.c:
	Likewise.
---
 ...-deref-pr108251-smp_fetch_ssl_fc_has_early-O2.c |    2 +-
 ...ull-deref-pr108251-smp_fetch_ssl_fc_has_early.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/gcc/testsuite/c-c++-common/analyzer/null-deref-pr108251-smp_fetch_ssl_fc_has_early-O2.c b/gcc/testsuite/c-c++-common/analyzer/null-deref-pr108251-smp_fetch_ssl_fc_has_early-O2.c
index c46ffe91a6b46..aaa2031b6dca4 100644
--- a/gcc/testsuite/c-c++-common/analyzer/null-deref-pr108251-smp_fetch_ssl_fc_has_early-O2.c
+++ b/gcc/testsuite/c-c++-common/analyzer/null-deref-pr108251-smp_fetch_ssl_fc_has_early-O2.c
@@ -61,7 +61,7 @@ static inline enum obj_type obj_type(const enum obj_type *t)
 }
 static inline struct connection *__objt_conn(enum obj_type *t)
 {
- return ((struct connection *)(((char *)(t)) - ((long)&((struct connection *)0)->obj_type)));
+ return ((struct connection *)(((char *)(t)) - ((long)&((struct connection *)0)->obj_type))); /* { dg-warning "unaligned pointer value" "warning" { target { short_enums && { ! c++ } } } } */
 }
 static inline struct connection *objt_conn(enum obj_type *t)
 {
diff --git a/gcc/testsuite/c-c++-common/analyzer/null-deref-pr108251-smp_fetch_ssl_fc_has_early.c b/gcc/testsuite/c-c++-common/analyzer/null-deref-pr108251-smp_fetch_ssl_fc_has_early.c
index ef34a76c50d63..6c96f5a76ef1c 100644
--- a/gcc/testsuite/c-c++-common/analyzer/null-deref-pr108251-smp_fetch_ssl_fc_has_early.c
+++ b/gcc/testsuite/c-c++-common/analyzer/null-deref-pr108251-smp_fetch_ssl_fc_has_early.c
@@ -60,7 +60,7 @@ static inline enum obj_type obj_type(const enum obj_type *t)
 }
 static inline struct connection *__objt_conn(enum obj_type *t)
 {
- return ((struct connection *)(((char *)(t)) - ((long)&((struct connection *)0)->obj_type)));
+ return ((struct connection *)(((char *)(t)) - ((long)&((struct connection *)0)->obj_type))); /* { dg-warning "unaligned pointer value" "warning" { target { short_enums && { ! c++ } } } } */
 }
 static inline struct connection *objt_conn(enum obj_type *t)
 {


-- 
Alexandre Oliva, happy hacker            https://FSFLA.org/blogs/lxo/
   Free Software Activist                   GNU Toolchain Engineer
More tolerance and less prejudice are key for inclusion and diversity
Excluding neuro-others for not behaving ""normal"" is *not* inclusive