Change x64 size checks to not apply to x32.

Rust contains various size checks conditional on target_arch = "x86_64",
but these checks were never intended to apply to
x86_64-unknown-linux-gnux32. Add target_pointer_width = "64" to the
conditions.

compiler/rustc_infer/src/infer/mod.rs

@@ -408,7 +408,7 @@ pub enum SubregionOrigin<'tcx> {
 }
 
 // `SubregionOrigin` is used a lot. Make sure it doesn't unintentionally get bigger.
-#[cfg(target_arch = "x86_64")]
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 static_assert_size!(SubregionOrigin<'_>, 32);
 
 /// Times when we replace late-bound regions with variables:

compiler/rustc_infer/src/lib.rs

@@ -27,7 +27,7 @@
 
 #[macro_use]
 extern crate rustc_macros;
-#[cfg(target_arch = "x86_64")]
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 #[macro_use]
 extern crate rustc_data_structures;
 #[macro_use]

compiler/rustc_infer/src/traits/mod.rs

@@ -56,7 +56,7 @@ pub type PredicateObligation<'tcx> = Obligation<'tcx, ty::Predicate<'tcx>>;
 pub type TraitObligation<'tcx> = Obligation<'tcx, ty::PolyTraitPredicate<'tcx>>;
 
 // `PredicateObligation` is used a lot. Make sure it doesn't unintentionally get bigger.
-#[cfg(target_arch = "x86_64")]
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 static_assert_size!(PredicateObligation<'_>, 32);
 
 pub type PredicateObligations<'tcx> = Vec<PredicateObligation<'tcx>>;