https://gcc.gnu.org/g:ea588988c193ee19b61bba5b99e039c9ca267abe
commit r16-2596-gea588988c193ee19b61bba5b99e039c9ca267abe
Author: Andrew Pinski <quic_apin...@quicinc.com>
Date: Mon Jul 28 20:22:53 2025 -0700
output: Move an special # (256) to a new macro
This is a followup to the review of mergability of CSWTCH patch
located at https://gcc.gnu.org/pipermail/gcc-patches/2025-July/690810.html.
Moves the special # (256) to a macro so it is not used bare in the source
and there is only the need to change it in one place.
This special # was added with r0-37392-g201556f0e00580 which added the
original mergeable
section support to gcc.
Pushed as obvious after build and test on x86_64.
gcc/ChangeLog:
* output.h (MAX_ALIGN_MERGABLE): New define.
* tree-switch-conversion.cc (switch_conversion::build_one_array):
Use MAX_ALIGN_MERGABLE instead of 256.
* varasm.cc (mergeable_string_section): Likewise
(mergeable_constant_section): Likewise
Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
Diff:
---
gcc/output.h | 3 +++
gcc/tree-switch-conversion.cc | 6 +++---
gcc/varasm.cc | 6 +++---
3 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/gcc/output.h b/gcc/output.h
index 5cc72ebee378..51c2d36f8f66 100644
--- a/gcc/output.h
+++ b/gcc/output.h
@@ -545,6 +545,9 @@ extern GTY(()) section *bss_noswitch_section;
extern GTY(()) section *in_section;
extern GTY(()) bool in_cold_section_p;
+/* MAX bit alignment for mergable sections. */
+#define MAX_ALIGN_MERGABLE 256
+
extern section *get_unnamed_section (unsigned int, void (*) (const char *),
const char *);
extern section *get_section (const char *, unsigned int, tree,
diff --git a/gcc/tree-switch-conversion.cc b/gcc/tree-switch-conversion.cc
index b3ae93d57e1e..04b357fca4c4 100644
--- a/gcc/tree-switch-conversion.cc
+++ b/gcc/tree-switch-conversion.cc
@@ -55,6 +55,7 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
MA
#include "hwint.h"
#include "internal-fn.h"
#include "diagnostic-core.h"
+#include "output.h"
/* ??? For lang_hooks.types.type_for_mode, but is there a word_mode
type in the GIMPLE type system that is language-independent? */
@@ -1038,9 +1039,8 @@ switch_conversion::build_one_array (int num, tree
arr_index_type,
if (tree_to_uhwi (DECL_SIZE (decl)) > DECL_ALIGN (decl))
{
unsigned HOST_WIDE_INT s = tree_to_uhwi (DECL_SIZE (decl));
- /* Only support up to 32bytes since that is what is
- supported for merging. */
- if (s <= 256)
+ /* Only support up to the max supported for merging. */
+ if (s <= MAX_ALIGN_MERGABLE)
SET_DECL_ALIGN (decl, HOST_WIDE_INT_1U << ceil_log2 (s));
}
diff --git a/gcc/varasm.cc b/gcc/varasm.cc
index 834cdefbe4f8..000ad9e26f6f 100644
--- a/gcc/varasm.cc
+++ b/gcc/varasm.cc
@@ -871,7 +871,7 @@ mergeable_string_section (tree decl ATTRIBUTE_UNUSED,
if (HAVE_GAS_SHF_MERGE && flag_merge_constants
&& TREE_CODE (decl) == STRING_CST
&& TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
- && align <= 256
+ && align <= MAX_ALIGN_MERGABLE
&& (len = int_size_in_bytes (TREE_TYPE (decl))) > 0
&& TREE_STRING_LENGTH (decl) == len)
{
@@ -885,7 +885,7 @@ mergeable_string_section (tree decl ATTRIBUTE_UNUSED,
mode = SCALAR_INT_TYPE_MODE (TREE_TYPE (TREE_TYPE (decl)));
modesize = GET_MODE_BITSIZE (mode);
- if (modesize >= 8 && modesize <= 256
+ if (modesize >= 8 && modesize <= MAX_ALIGN_MERGABLE
&& (modesize & (modesize - 1)) == 0)
{
if (align < modesize)
@@ -926,7 +926,7 @@ mergeable_constant_section (unsigned HOST_WIDE_INT
size_bits,
if (HAVE_GAS_SHF_MERGE && flag_merge_constants
&& size_bits <= align
&& align >= 8
- && align <= 256
+ && align <= MAX_ALIGN_MERGABLE
&& (align & (align - 1)) == 0)
{
const char *prefix = function_mergeable_rodata_prefix ();
