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* [gcc r12-1444] c-family: Copy DECL_USER_ALIGN even if DECL_ALIGN is similar.
@ 2021-06-15 8:03 Robin Dapp
0 siblings, 0 replies; only message in thread
From: Robin Dapp @ 2021-06-15 8:03 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:ba2eef033e59d80fde35d0cc3acf4d82f7706e60
commit r12-1444-gba2eef033e59d80fde35d0cc3acf4d82f7706e60
Author: Robin Dapp <rdapp@linux.ibm.com>
Date: Tue Jun 15 09:06:02 2021 +0200
c-family: Copy DECL_USER_ALIGN even if DECL_ALIGN is similar.
When re-declaring a function with differing attributes DECL_USER_ALIGN
is usually not merged/copied when DECL_ALIGN is similar. On s390 this
will cause a warning message not to be shown. Similarly, we warned
about the wrong alignment when short-circuiting an alignment initialization in
common_handle_aligned_attribute ().
Fix this by copying DECL_USER_ALIGN even if DECL_ALIGN is similar as
well as getting rid of the short-circuited initialization.
gcc/c-family/ChangeLog:
* c-attribs.c (common_handle_aligned_attribute): Remove short
circuit and dead code.
gcc/c/ChangeLog:
* c-decl.c (merge_decls): Copy DECL_USER_ALIGN if DECL_ALIGN is
similar.
gcc/cp/ChangeLog:
* decl.c (duplicate_decls): Likewise.
Diff:
---
gcc/c-family/c-attribs.c | 30 +++++++-----------------------
gcc/c/c-decl.c | 3 +++
gcc/cp/decl.c | 4 ++++
3 files changed, 14 insertions(+), 23 deletions(-)
diff --git a/gcc/c-family/c-attribs.c b/gcc/c-family/c-attribs.c
index 6bf492afcc0..e60fb31d8c8 100644
--- a/gcc/c-family/c-attribs.c
+++ b/gcc/c-family/c-attribs.c
@@ -2338,14 +2338,17 @@ common_handle_aligned_attribute (tree *node, tree name, tree args, int flags,
*no_add_attrs = true;
}
else if (TREE_CODE (decl) == FUNCTION_DECL
- && ((curalign = DECL_ALIGN (decl)) > bitalign
- || ((lastalign = DECL_ALIGN (last_decl)) > bitalign)))
+ && (((curalign = DECL_ALIGN (decl)) > bitalign)
+ | ((lastalign = DECL_ALIGN (last_decl)) > bitalign)))
{
/* Either a prior attribute on the same declaration or one
on a prior declaration of the same function specifies
stricter alignment than this attribute. */
- bool note = lastalign != 0;
- if (lastalign)
+ bool note = (lastalign > curalign
+ || (lastalign == curalign
+ && (DECL_USER_ALIGN (last_decl)
+ > DECL_USER_ALIGN (decl))));
+ if (note)
curalign = lastalign;
curalign /= BITS_PER_UNIT;
@@ -2390,25 +2393,6 @@ common_handle_aligned_attribute (tree *node, tree name, tree args, int flags,
This formally comes from the c++11 specification but we are
doing it for the GNU attribute syntax as well. */
*no_add_attrs = true;
- else if (!warn_if_not_aligned_p
- && TREE_CODE (decl) == FUNCTION_DECL
- && DECL_ALIGN (decl) > bitalign)
- {
- /* Don't warn for function alignment here if warn_if_not_aligned_p
- is true. It will be warned about later. */
- if (DECL_USER_ALIGN (decl))
- {
- /* Only reject attempts to relax/override an alignment
- explicitly specified previously and accept declarations
- that appear to relax the implicit function alignment for
- the target. Both increasing and increasing the alignment
- set by -falign-functions setting is permitted. */
- error ("alignment for %q+D was previously specified as %d "
- "and may not be decreased", decl,
- DECL_ALIGN (decl) / BITS_PER_UNIT);
- *no_add_attrs = true;
- }
- }
else if (warn_if_not_aligned_p
&& TREE_CODE (decl) == FIELD_DECL
&& !DECL_C_BIT_FIELD (decl))
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index a86792bbe06..7cd13a593eb 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -2620,6 +2620,9 @@ merge_decls (tree newdecl, tree olddecl, tree newtype, tree oldtype)
SET_DECL_ALIGN (newdecl, DECL_ALIGN (olddecl));
DECL_USER_ALIGN (newdecl) |= DECL_USER_ALIGN (olddecl);
}
+ else if (DECL_ALIGN (olddecl) == DECL_ALIGN (newdecl)
+ && DECL_USER_ALIGN (olddecl) != DECL_USER_ALIGN (newdecl))
+ DECL_USER_ALIGN (newdecl) = 1;
if (DECL_WARN_IF_NOT_ALIGN (olddecl)
> DECL_WARN_IF_NOT_ALIGN (newdecl))
SET_DECL_WARN_IF_NOT_ALIGN (newdecl,
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index f5596b689a2..02772e94763 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -2805,6 +2805,10 @@ duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden)
SET_DECL_ALIGN (newdecl, DECL_ALIGN (olddecl));
DECL_USER_ALIGN (newdecl) |= DECL_USER_ALIGN (olddecl);
}
+ else if (DECL_ALIGN (olddecl) == DECL_ALIGN (newdecl)
+ && DECL_USER_ALIGN (olddecl) != DECL_USER_ALIGN (newdecl))
+ DECL_USER_ALIGN (newdecl) = 1;
+
DECL_USER_ALIGN (olddecl) = DECL_USER_ALIGN (newdecl);
if (DECL_WARN_IF_NOT_ALIGN (olddecl)
> DECL_WARN_IF_NOT_ALIGN (newdecl))
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