https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118537
--- Comment #18 from Julian Andres Klode <j...@jak-linux.org> ---
(In reply to Sam James from comment #17)
> (In reply to Julian Andres Klode from comment #16)
>
> I built apt and couldn't reproduce it using this yet with tip of 14 release
> branch and trunk too.
I need to try building gcc-14 branch itself and see for myself, also if I can
still reproduce it on AWS, then I can bisect it to the commit introducing the
issue.
Meanwhile, my initial attempt at cvise on the full .ii was not fruitful as I
mocked that up using if (Encoding != Closes) exit(42) and cvise helpfully
trimmed it down to Encoding != Closes; exit(42) - that is, it always failed.
I started a second attempt where I split out the offending
BaseHttpMethod::Loop() into its own source file and then cvised that and that
reduced it to:
void BaseHttpMethod::Loop() {
while (1) {
Run();
Server = CreateServerState(URI(Queue->Uri));
Server->Open();
RequestState Req(this, Server.get());
switch (Server->RunHeaders(Req, Queue->Uri));
}
}
When downloading over https (i.e. Server->Open() makes OpenSSL calls), I get
the error, without OpenSSL calls, I do not get the error, so it sounds like
something messes up (register?) state there.
This boils down to:
isb
// 0 "" 2
// basehttp-loop.cc:12: time(&Date);
#NO_APP
ldr x0, [sp, 16] //, %sfp
// basehttp-loop.cc:11: : Server() {
str d15, [sp, 48] // tmp332, MEM <vector(2) unsigned int> [(void
*)&Req]
// basehttp-loop.cc:12: time(&Date);
bl time //
// basehttp-loop.cc:13: assert(Encoding == Closes);
ldr w0, [sp, 48] //, Req.Encoding
cmp w0, 1 // Req.Encoding,
bne .L56 //,
// /usr/include/aarch64-linux-gnu/bits/stdio2.h:118: return __printf_chk
(__USE_FORTIFY_LEVEL - 1, __fmt, __va_arg_pack ());
adrp x1, .LC3 // tmp267,
mov w0, 2 //,
add x1, x1, :lo12:.LC3 //, tmp267,
bl __printf_chk //
.LEHE3:
// basehttp-loop.cc:41: __asm__("isb");
#APP
// 41 "basehttp-loop.cc" 1
isb
Now per ARM, `D part of V8-V15 need to be saved`, but the only other mention of
`d15` is
ldr d15, [x0, #:lo12:.LC4] // tmp332,
earlier in the function way before we call any of the other functions.
The question I'm not sure is D part of V15 caller-saved or callee-saved?
