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* [Bug target/107238] New: aarch64: Wrong code converting pointer to __int128
@ 2022-10-12 16:25 acoplan at gcc dot gnu.org
2022-10-12 23:21 ` [Bug target/107238] " pinskia at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: acoplan at gcc dot gnu.org @ 2022-10-12 16:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107238
Bug ID: 107238
Summary: aarch64: Wrong code converting pointer to __int128
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: acoplan at gcc dot gnu.org
Target Milestone: ---
For this testcase:
__int128 f(int *p) {
return (__int128)p;
}
AArch64 GCC at -O2 generates:
f:
asr x1, x0, 63
ret
i.e. it sign-extends the pointer, but I think it should be a zero extend
instead. The ABI [1] says:
> Code and data pointers are either 64-bit or 32-bit unsigned types.
Indeed LLVM does a zero-extend:
f: // @f
mov x1, xzr
ret
[1] :
https://github.com/ARM-software/abi-aa/blob/main/aapcs64/aapcs64.rst#pointers
^ permalink raw reply [flat|nested] 4+ messages in thread* [Bug target/107238] aarch64: Wrong code converting pointer to __int128 2022-10-12 16:25 [Bug target/107238] New: aarch64: Wrong code converting pointer to __int128 acoplan at gcc dot gnu.org @ 2022-10-12 23:21 ` pinskia at gcc dot gnu.org 2022-10-12 23:25 ` pinskia at gcc dot gnu.org 2022-10-13 0:12 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2022-10-12 23:21 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107238 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |INVALID Status|UNCONFIRMED |RESOLVED --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- https://gcc.gnu.org/onlinedocs/gcc-12.2.0/gcc/Arrays-and-pointers-implementation.html#Arrays-and-pointers-implementation > A cast from integer to pointer discards most-significant bits if the pointer representation is smaller than the integer type, extends according to the signedness of the integer type if the pointer representation is larger than the integer type, otherwise the bits are unchanged. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/107238] aarch64: Wrong code converting pointer to __int128 2022-10-12 16:25 [Bug target/107238] New: aarch64: Wrong code converting pointer to __int128 acoplan at gcc dot gnu.org 2022-10-12 23:21 ` [Bug target/107238] " pinskia at gcc dot gnu.org @ 2022-10-12 23:25 ` pinskia at gcc dot gnu.org 2022-10-13 0:12 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2022-10-12 23:25 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107238 --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- clang does not even define the behavior here even though it should be as it is an implementation defined behavior. File a bug with clang about not documenting their behavior ... ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/107238] aarch64: Wrong code converting pointer to __int128 2022-10-12 16:25 [Bug target/107238] New: aarch64: Wrong code converting pointer to __int128 acoplan at gcc dot gnu.org 2022-10-12 23:21 ` [Bug target/107238] " pinskia at gcc dot gnu.org 2022-10-12 23:25 ` pinskia at gcc dot gnu.org @ 2022-10-13 0:12 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2022-10-13 0:12 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107238 --- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #2) > File a bug with clang about not documenting their behavior ... Oh there is one already: https://github.com/llvm/llvm-project/issues/11644 Still open after (almost) 10 years. ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-10-13 0:12 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-10-12 16:25 [Bug target/107238] New: aarch64: Wrong code converting pointer to __int128 acoplan at gcc dot gnu.org 2022-10-12 23:21 ` [Bug target/107238] " pinskia at gcc dot gnu.org 2022-10-12 23:25 ` pinskia at gcc dot gnu.org 2022-10-13 0:12 ` pinskia at gcc dot gnu.org
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