[Bug tree-optimization/78821] GCC7: Copying whole 32 bits structure field by field not optimised into copying whole 32 bits at once
ubizjak at gmail dot com
gcc-bugzilla@gcc.gnu.org
Mon Nov 20 10:45:00 GMT 2017
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78821
--- Comment #17 from Uroš Bizjak <ubizjak at gmail dot com> ---
Hm, even with the latest patch, the testcase from comment #5:
typedef __SIZE_TYPE__ size_t;
void baz (char *buf, unsigned int data)
{
buf[0] = data;
buf[1] = data >> 8;
buf[2] = ~data >> 8;
buf[3] = ~data;
}
still compiles to:
movl %esi, %eax
movw %si, (%rdi)
notl %esi
notl %eax
movb %sil, 3(%rdi)
movb %ah, 2(%rdi)
ret
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