Auto merge of #90984 - matthiaskrgr:rollup-j5bs96a, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #89610 (warn on must_use use on async fn's)
 - #90667 (Improve diagnostics when a static lifetime is expected)
 - #90687 (Permit const panics in stable const contexts in stdlib)
 - #90772 (Add Vec::retain_mut)
 - #90861 (Print escaped string if char literal has multiple characters, but only one printable character)
 - #90884 (Fix span for non-satisfied trivial trait bounds)
 - #90900 (Remove workaround for the forward progress handling in LLVM)
 - #90901 (Improve ManuallyDrop suggestion)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

2 files changed, 0 insertions, 15 deletions

diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index a9471f7b771..c8f388bfa1d 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -980,17 +980,6 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             }
 
             mir::TerminatorKind::Goto { target } => {
-                if bb == target {
-                    // This is an unconditional branch back to this same basic block. That means we
-                    // have something like a `loop {}` statement. LLVM versions before 12.0
-                    // miscompile this because they assume forward progress. For older versions
-                    // try to handle just this specific case which comes up commonly in practice
-                    // (e.g., in embedded code).
-                    //
-                    // NB: the `sideeffect` currently checks for the LLVM version used internally.
-                    bx.sideeffect();
-                }
-
                 helper.funclet_br(self, &mut bx, target);
             }
 
diff --git a/compiler/rustc_codegen_ssa/src/traits/intrinsic.rs b/compiler/rustc_codegen_ssa/src/traits/intrinsic.rs
index 78bf22ef9f2..02be6cd360c 100644
--- a/compiler/rustc_codegen_ssa/src/traits/intrinsic.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/intrinsic.rs
@@ -20,10 +20,6 @@ pub trait IntrinsicCallMethods<'tcx>: BackendTypes {
     fn abort(&mut self);
     fn assume(&mut self, val: Self::Value);
     fn expect(&mut self, cond: Self::Value, expected: bool) -> Self::Value;
-    /// Emits a forced side effect.
-    ///
-    /// Currently has any effect only when LLVM versions prior to 12.0 are used as the backend.
-    fn sideeffect(&mut self);
     /// Trait method used to test whether a given pointer is associated with a type identifier.
     fn type_test(&mut self, pointer: Self::Value, typeid: Self::Value) -> Self::Value;
     /// Trait method used to inject `va_start` on the "spoofed" `VaListImpl` in