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From: "absoler at smail dot nju.edu.cn" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/114688] New: repeat load argument of an inline function Date: Thu, 11 Apr 2024 06:56:45 +0000 [thread overview] Message-ID: <bug-114688-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114688 Bug ID: 114688 Summary: repeat load argument of an inline function Product: gcc Version: 13.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: rtl-optimization Assignee: unassigned at gcc dot gnu.org Reporter: absoler at smail dot nju.edu.cn Target Milestone: --- Hi, here's the case, regression from gcc-10, x86-64 ``` char g; int v; void foo(char p_17); void func_1() { foo(g); } void foo(char c) { v = (char)(2 - c) & c; } ``` -O2 produce this for `func_1`: ``` <func_1>: foo(): 401130: mov $0x2,%eax 401135: sub 0x2ef5(%rip),%al # 404030 <g> 40113b: and 0x2eef(%rip),%al # 404030 <g> 401141: movsbl %al,%eax 401144: mov %eax,0x2ee2(%rip) # 40402c <v> func_1(): 40114a: retq ``` it seems register allocator feels it's better to repeat load `g` instead of generating an extra `mov` to load it. while clang-trunk choose to do so: https://godbolt.org/z/bqxz8fMYn
next reply other threads:[~2024-04-11 6:56 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-04-11 6:56 absoler at smail dot nju.edu.cn [this message] 2024-04-11 7:06 ` [Bug rtl-optimization/114688] " rguenth at gcc dot gnu.org 2024-04-11 7:07 ` pinskia at gcc dot gnu.org
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