https://bugs.llvm.org/show_bug.cgi?id=39683
Bug ID: 39683
Summary: clang silently ignores trivial_abi in some cases
Product: clang
Version: trunk
Hardware: PC
OS: All
Status: NEW
Severity: enhancement
Priority: P
Component: C++
Assignee: [email protected]
Reporter: [email protected]
CC: [email protected], [email protected],
[email protected], [email protected],
[email protected]
Target: x86_64-apple-darwin18.2.0
In the following code, the class Test is marked trivial_abi (and is not a
template class), and Clang does not produce any warnings about trivial_abi when
compiling it, yet for the function test() returning a value of that class,
Clang's generated code returns it through memory rather than a register.
I'm not sure whether this class should actually be eligible for trivial_abi or
not, but if not, there definitely should be a warning.
If you change the definition by adding an additional non-template move
constructor, then trivial_abi starts being respected:
+ Test(Test &&other) { x = other.x; }
Tested on latest trunk targeting macOS.
--
struct Test {
int x;
Test(int x) : x(x) {}
template <typename T>
Test(T &&other) { x = other.x; }
Test(const Test &) = delete;
template <typename T>
Test &operator=(T &&other) { x = other.x; }
Test &operator=(const Test &) = delete;
} __attribute__((trivial_abi));
Test test() {
return Test(42);
}
--
You are receiving this mail because:
You are on the CC list for the bug._______________________________________________
llvm-bugs mailing list
[email protected]
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
