Auto merge of rust-lang#132434 - tgross35:f128-tests, r=workingjubilee

Update `compiler-builtins` and enable f128 tests on all non-buggy platforms

Update compiler_builtins to 0.1.138 and pin it. This updates to a new version of builtins that includes [1], which was
the last blocker to us enabling `f128` tests on all platforms.

With that, we now provide symbols necessary to work with `f128` everywhere. This means that we are no longer restricted to systems that provide `f128` symbols themselves, and can enable tests by default.

There are still a handful of platforms that need to remain disabled because of bugs and some that had to get updated.

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

[1]: rust-lang/compiler-builtins#624

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

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"] }

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',

std/build.rs

@@ -122,19 +122,24 @@ 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>
+        ("mips64" | "mips64r6", _) => false,
         // Selection bug <https://github.com/llvm/llvm-project/issues/95471>
         ("nvptx64", _) => false,
+        // ABI bugs <https://github.com/rust-lang/rust/issues/125109> et al. (full
+        // list at <https://github.com/rust-lang/rust/issues/116909>)
+        ("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.