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“error: invalid operand for inline asm constraint 'i'” with enum members #42974
Description
Hello,
It looks like in some cases (ie. not enough optimizations turned on), enum members cannot be used as 'i' operands for inline assembly:
#![feature(asm)]
#[repr(usize)]
enum Foo {
Bar = 1,
}
fn main() {
unsafe {
asm!("" :: "i" (9isize), "i" (Foo::Bar));
}
}http://play.integer32.com/?gist=befc6872b583ffaa1609f081b7536b50&version=nightly
Given this is (with macros, maybe?) the only use I can think of 'i' operands, I think it is reasonable to say the 'i' operand is currently broken.
This would be solved by even the slightest level of constant folding, so I think even in debug mode it should actually constant fold to something that builds, and not have successful compilation be dependent of the specific compiler version and flags used (as is currently the case).
Reacted by Benjamin Brittain
Activity
parched commentedon Jun 30, 2017
Same underlying issue as #41337 I guess.
eddyb commentedon Mar 13, 2020
Fix might be easy, see #41337 (comment).
Amanieu commentedon May 22, 2020
This issue does not apply to the new
asm!(RFC 2850) which has stricter checks on the types that can be used as asm operands.The legacy
llvm_asm!is deprecated and is no longer maintained.