tests: adjust expectation for f128 abi on Windows

[durin42]

llvm/llvm-project@5ee1c0b updates llvm to match the documented calling convention to pass f128 indirectly.

@rustbot label llvm-main

try-job: dist-x86_64-msvc
try-job: dist-x86_64-mingw
try-job: x86_64-msvc-1
try-job: x86_64-msvc-2
try-job: x86_64-mingw-1
try-job: x86_64-mingw-2

[rustbot]

r? @Mark-Simulacrum

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[Mark-Simulacrum]

r? @tgross35

Looks OK but want to get someone more familiar with i128 to review.

[tgross35]

I meant to send a patch once my LLVM change merged, but we should also update our codegen to match. Could you change

rust/compiler/rustc_target/src/callconv/x86_win64.rs

Lines 26 to 43 in 8279176

	if is_ret && matches!(scalar.primitive(), Primitive::Int(Integer::I128, _)) {
	if cx.target_spec().rustc_abi == Some(RustcAbi::X86Softfloat) {
	// Use the native `i128` LLVM type for the softfloat ABI -- in other words, adjust nothing.
	} else {
	// `i128` is returned in xmm0 by Clang and GCC
	// FIXME(#134288): This may change for the `-msvc` targets in the future.
	let reg = Reg { kind: RegKind::Vector, size: Size::from_bits(128) };
	a.cast_to(reg);
	}
	} else if a.layout.size.bytes() > 8
	&& !matches!(scalar.primitive(), Primitive::Float(Float::F128))
	{
	// Match what LLVM does for `f128` so that `compiler-builtins` builtins match up
	// with what LLVM expects.
	a.make_indirect();
	} else {
	a.extend_integer_width_to(32);
	}

so i128 and f128 use the same ABI? That probably means a codegen test update.

[tgross35]

Could you add something like // FIXME(llvm21) remove xmm1 once Rust's LLVM has the ABI change so we clean this up later?

Cc @beetrees since iirc you authored this test

[tgross35]

Actually if we update our codegen to match i128, the options shouldn't be needed since it will always be (%rdx).

[tgross35]

You should be able to take the CC change from #137779.