On 5/30/2022 9:35 PM, Takayuki 'January June' Suwa via Gcc-patches wrote:
Hi all,
In some targets, initialization code for char array may be split into two
parts even if the initialization consists of all zeros:
/* example */
extern void foo(char*);
void test(void) {
char a[256] = { 0, 0, 0, 0, 0, 0, 0, 0, 0 };
foo(a);
}
;; Xtensa (xtensa-lx106)
.LC0:
.string ""
.string ""
.string ""
.string ""
.string ""
.string ""
.string ""
.string ""
.string ""
.string ""
.zero 246
test:
movi a9, 0x110
sub sp, sp, a9
l32r a3, .LC1
movi.n a4, 0xa
mov.n a2, sp
s32i a0, sp, 268
call0 memcpy
movi a4, 0xf6
movi.n a3, 0
addi.n a2, sp, 10
call0 memset
mov.n a2, sp
call0 foo
l32i a0, sp, 268
movi a9, 0x110
add.n sp, sp, a9
ret.n
;; H8/300 (-mh -mint32)
.LC0:
.string ""
.string ""
.string ""
.string ""
.string ""
.string ""
.string ""
.string ""
.string ""
.string ""
.zero 246
_test:
sub.l #256,er7
sub.l er2,er2
add.b #10,r2l
mov.l #.LC0,er1
mov.l er7,er0
jsr @_memcpy
sub.l er2,er2
add.b #246,r2l
sub.l er1,er1
sub.l er0,er0
add.b #10,r0l
add.l er7,er0
jsr @_memset
mov.l er7,er0
jsr @_foo
add.l #256,er7
rts
i386 target (both 32 and 64bit) does not show such behavior.
gcc/ChangeLog:
* expr.cc (store_expr): Add check if the initialization content
consists of all zeros.
It's not entirely clear what you're trying to accomplish. Is it the
.zero which allocates space in the .rodata you're trying to remove? If
so, it looks like that is already addressed on the trunk to me (I
checked H8 with and without optimization).
jeff
