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From: "ardb at kernel dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/102926] TLS register value is spilled to the stack instead of reloaded from the system register Date: Mon, 25 Oct 2021 14:46:49 +0000 [thread overview] Message-ID: <bug-102926-4-YHdTtrw1WW@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-102926-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102926 --- Comment #5 from Ard Biesheuvel <ardb at kernel dot org> --- Actually, I can reproduce the same behavior without the TLS register, where the result of a MOVW/MOVT immediate assignment is also spilled to the stack. int ll[2]; int foo(int); int bar(void) { int *l = ll; return foo(l[0]) + l[1]; } will produce this for armv7-a (with [r4-r11] fixed) push {fp, lr} movw r3, #:lower16:.LANCHOR0 movt r3, #:upper16:.LANCHOR0 add fp, sp, #4 sub sp, sp, #8 ldr r0, [r3] str r3, [fp, #-8] bl foo ldr r3, [fp, #-8] ldr r3, [r3, #4] add r0, r0, r3 sub sp, fp, #4 @ sp needed pop {fp, pc} whereas pre-v7 gives me ldr r3, .L4 push {fp, lr} add fp, sp, #4 ldr r0, [r3] bl foo ldr r3, .L4 ldr r3, [r3, #4] add r0, r0, r3 pop {fp, pc} i.e., the address is simply reloaded from the literal pool rather than spilled.
next prev parent reply other threads:[~2021-10-25 14:46 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-10-25 11:35 [Bug target/102926] New: " ardb at kernel dot org 2021-10-25 11:50 ` [Bug target/102926] " pinskia at gcc dot gnu.org 2021-10-25 12:02 ` rguenth at gcc dot gnu.org 2021-10-25 12:03 ` ardb at kernel dot org 2021-10-25 12:12 ` pinskia at gcc dot gnu.org 2021-10-25 14:46 ` ardb at kernel dot org [this message] 2021-10-25 15:24 ` rsandifo at gcc dot gnu.org
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