1 files changed, 12 insertions, 15 deletions
diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs
index f7546039540..1a1b4ae3831 100644
--- a/compiler/rustc_codegen_llvm/src/builder.rs
+++ b/compiler/rustc_codegen_llvm/src/builder.rs
@@ -17,7 +17,7 @@ use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_hir::def_id::DefId;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
 use rustc_middle::ty::layout::{
-    FnAbiError, FnAbiOfHelpers, FnAbiRequest, HasTyCtxt, LayoutError, LayoutOfHelpers, TyAndLayout,
+    FnAbiError, FnAbiOfHelpers, FnAbiRequest, LayoutError, LayoutOfHelpers, TyAndLayout,
 };
 use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
 use rustc_sanitizers::{cfi, kcfi};
@@ -1704,12 +1704,21 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
         kcfi_bundle
     }
 
+    /// Emits a call to `llvm.instrprof.mcdc.parameters`.
+    ///
+    /// This doesn't produce any code directly, but is used as input by
+    /// the LLVM pass that handles coverage instrumentation.
+    ///
+    /// (See clang's [`CodeGenPGO::emitMCDCParameters`] for comparison.)
+    ///
+    /// [`CodeGenPGO::emitMCDCParameters`]:
+    ///     https://github.com/rust-lang/llvm-project/blob/5399a24/clang/lib/CodeGen/CodeGenPGO.cpp#L1124
     pub(crate) fn mcdc_parameters(
         &mut self,
         fn_name: &'ll Value,
         hash: &'ll Value,
         bitmap_bytes: &'ll Value,
-    ) -> &'ll Value {
+    ) {
         debug!("mcdc_parameters() with args ({:?}, {:?}, {:?})", fn_name, hash, bitmap_bytes);
 
         assert!(llvm_util::get_version() >= (18, 0, 0), "MCDC intrinsics require LLVM 18 or later");
@@ -1732,17 +1741,6 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
                 [].as_ptr(),
                 0 as c_uint,
             );
-            // Create condition bitmap named `mcdc.addr`.
-            let mut bx = Builder::with_cx(self.cx);
-            bx.position_at_start(llvm::LLVMGetFirstBasicBlock(self.llfn()));
-            let cond_bitmap = {
-                let alloca =
-                    llvm::LLVMBuildAlloca(bx.llbuilder, bx.cx.type_i32(), c"mcdc.addr".as_ptr());
-                llvm::LLVMSetAlignment(alloca, 4);
-                alloca
-            };
-            bx.store(self.const_i32(0), cond_bitmap, self.tcx().data_layout.i32_align.abi);
-            cond_bitmap
         }
     }
 
@@ -1785,8 +1783,7 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
                 0 as c_uint,
             );
         }
-        let i32_align = self.tcx().data_layout.i32_align.abi;
-        self.store(self.const_i32(0), mcdc_temp, i32_align);
+        self.store(self.const_i32(0), mcdc_temp, self.tcx.data_layout.i32_align.abi);
     }
 
     pub(crate) fn mcdc_condbitmap_update(