Auto merge of #132434 - tgross35:f128-tests, r=<try>

Enable f128 tests on all non-buggy platforms 🎉

With the `compiler-builtins` update to 0.1.137 [1], we now provide symbols necessary to work with `f128` everywhere. This means that we are no longer restricted to 64-bit linux, and can enable tests by default.

There are still a handful of platforms that need to remain disabled because of bugs.

Math support is still off by default since those symbols are not yet available.

[1]: #132433

try-job: test-various
try-job: i686-gnu-nopt

library/Cargo.lock

@@ -61,9 +61,9 @@ dependencies = [
 
 [[package]]
 name = "compiler_builtins"
-version = "0.1.136"
+version = "0.1.138"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "33ccee9dd499d7ada4c81533382ce87e88c52b0676c7320b2e617d29e1bb3a3f"
+checksum = "53f0ea7fff95b51f84371588f06062557e96bbe363d2b36218ddb806f3ca8611"
 dependencies = [
  "cc",
  "rustc-std-workspace-core",

library/alloc/Cargo.toml

@@ -10,7 +10,7 @@ edition = "2021"
 
 [dependencies]
 core = { path = "../core" }
-compiler_builtins = { version = "0.1.136", features = ['rustc-dep-of-std'] }
+compiler_builtins = { version = "=0.1.138", features = ['rustc-dep-of-std'] }
 
 [dev-dependencies]
 rand = { version = "0.8.5", default-features = false, features = ["alloc"] }

library/std/Cargo.toml

@@ -17,7 +17,7 @@ cfg-if = { version = "1.0", features = ['rustc-dep-of-std'] }
 panic_unwind = { path = "../panic_unwind", optional = true }
 panic_abort = { path = "../panic_abort" }
 core = { path = "../core", public = true }
-compiler_builtins = { version = "0.1.136" }
+compiler_builtins = { version = "=0.1.138" }
 unwind = { path = "../unwind" }
 hashbrown = { version = "0.15", default-features = false, features = [
     'rustc-dep-of-std',

library/std/build.rs

@@ -122,19 +122,23 @@ fn main() {
         _ if is_miri => true,
         // Unsupported <https://github.com/llvm/llvm-project/issues/94434>
         ("arm64ec", _) => false,
-        // ABI and precision bugs <https://github.com/rust-lang/rust/issues/125109>
-        // <https://github.com/rust-lang/rust/issues/125102>
-        ("powerpc" | "powerpc64", _) => false,
+        // Selection bug <https://github.com/llvm/llvm-project/issues/96432>
+        ("mips" | "mips64" | "mips32r6" | "mips64r6", _) => false,
         // Selection bug <https://github.com/llvm/llvm-project/issues/95471>
         ("nvptx64", _) => false,
+        // ABI and precision bugs <https://github.com/rust-lang/rust/issues/125109>
+        ("powerpc" | "powerpc64", _) => false,
         // ABI unsupported  <https://github.com/llvm/llvm-project/issues/41838>
         ("sparc", _) => false,
+        // Stack alignment bug <https://github.com/llvm/llvm-project/issues/77401>. NB: tests may
+        // not fail if our compiler-builtins is linked.
+        ("x86", _) => false,
         // MinGW ABI bugs <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115054>
         ("x86_64", "windows") if target_env == "gnu" && target_abi != "llvm" => false,
-        // 64-bit Linux is about the only platform to have f128 symbols by default
-        (_, "linux") if target_pointer_width == 64 => true,
-        // Almost all OSs are missing symbol. compiler-builtins will have to add them.
-        _ => false,
+        // There are no known problems on other platforms, so the only requirement is that symbols
+        // are available. `compiler-builtins` provides all symbols required for core `f128`
+        // support, so this should work for everything else.
+        _ => true,
     };
 
     // Configure platforms that have reliable basics but may have unreliable math.