https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116576
Bug ID: 116576
Summary: `INT64_MAX` and `-Oz`
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: lh_mouse at 126 dot com
Target Milestone: ---
For this simple function:
```
int64_t make_value(void) { return INT64_MAX; }
```
Both GCC and Clang generate an 8-byte `movabs` which adds up to 10 bytes:
```
48 b8 ffffffffffffff7f ; mov rax, 0x7fffffffffffffff
; (10 bytes; no dependency)
```
When we do `-Oz` we otpimize for size and do not care about the false
dependency, and this can be accomplished in only 7 bytes:
```
48 83 c8 ff ; or rax, -1
48 d1 e8 ; shr rax
; (7 bytes; input dependency on rax)
```
