diff --git a/compiler/rustc_codegen_gcc/src/intrinsic/mod.rs b/compiler/rustc_codegen_gcc/src/intrinsic/mod.rs
index ff1ae2d9d792c..73be25ba92b7e 100644
--- a/compiler/rustc_codegen_gcc/src/intrinsic/mod.rs
+++ b/compiler/rustc_codegen_gcc/src/intrinsic/mod.rs
@@ -23,7 +23,7 @@ use rustc_codegen_ssa::traits::{
 use rustc_middle::bug;
 #[cfg(feature = "master")]
 use rustc_middle::ty::layout::FnAbiOf;
-use rustc_middle::ty::layout::{HasTypingEnv, LayoutOf};
+use rustc_middle::ty::layout::LayoutOf;
 use rustc_middle::ty::{self, Instance, Ty};
 use rustc_span::{Span, Symbol, sym};
 use rustc_target::callconv::{ArgAbi, PassMode};
@@ -205,21 +205,10 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tc
         span: Span,
     ) -> Result<(), Instance<'tcx>> {
         let tcx = self.tcx;
-        let callee_ty = instance.ty(tcx, self.typing_env());
 
-        let (def_id, fn_args) = match *callee_ty.kind() {
-            ty::FnDef(def_id, fn_args) => (def_id, fn_args),
-            _ => bug!("expected fn item type, found {}", callee_ty),
-        };
-
-        let sig = callee_ty.fn_sig(tcx);
-        let sig = tcx.normalize_erasing_late_bound_regions(self.typing_env(), sig);
-        let arg_tys = sig.inputs();
-        let ret_ty = sig.output();
-        let name = tcx.item_name(def_id);
+        let name = tcx.item_name(instance.def_id());
         let name_str = name.as_str();
-
-        let llret_ty = self.layout_of(ret_ty).gcc_type(self);
+        let fn_args = instance.args;
 
         let simple = get_simple_intrinsic(self, name);
         let simple_func = get_simple_function(self, name);
@@ -320,8 +309,7 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tc
             | sym::rotate_right
             | sym::saturating_add
             | sym::saturating_sub => {
-                let ty = arg_tys[0];
-                match int_type_width_signed(ty, self) {
+                match int_type_width_signed(args[0].layout.ty, self) {
                     Some((width, signed)) => match name {
                         sym::ctlz | sym::cttz => {
                             let func = self.current_func.borrow().expect("func");
@@ -400,7 +388,7 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tc
                         tcx.dcx().emit_err(InvalidMonomorphization::BasicIntegerType {
                             span,
                             name,
-                            ty,
+                            ty: args[0].layout.ty,
                         });
                         return Ok(());
                     }
@@ -492,7 +480,14 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tc
             }
 
             _ if name_str.starts_with("simd_") => {
-                match generic_simd_intrinsic(self, name, callee_ty, args, ret_ty, llret_ty, span) {
+                match generic_simd_intrinsic(
+                    self,
+                    name,
+                    args,
+                    result.layout.ty,
+                    result.layout.gcc_type(self),
+                    span,
+                ) {
                     Ok(value) => value,
                     Err(()) => return Ok(()),
                 }
@@ -503,13 +498,10 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tc
         };
 
         if result.layout.ty.is_bool() {
-            OperandRef::from_immediate_or_packed_pair(self, value, result.layout)
-                .val
-                .store(self, result);
+            let val = self.from_immediate(value);
+            self.store_to_place(val, result.val);
         } else if !result.layout.ty.is_unit() {
-            let ptr_llty = self.type_ptr_to(result.layout.gcc_type(self));
-            let ptr = self.pointercast(result.val.llval, ptr_llty);
-            self.store(value, ptr, result.val.align);
+            self.store_to_place(value, result.val);
         }
         Ok(())
     }
diff --git a/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs b/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs
index b897d07924914..82ef0d0b13a45 100644
--- a/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs
+++ b/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs
@@ -28,7 +28,6 @@ use crate::context::CodegenCx;
 pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
     bx: &mut Builder<'a, 'gcc, 'tcx>,
     name: Symbol,
-    callee_ty: Ty<'tcx>,
     args: &[OperandRef<'tcx, RValue<'gcc>>],
     ret_ty: Ty<'tcx>,
     llret_ty: Type<'gcc>,
@@ -54,24 +53,17 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         };
     }
 
-    let tcx = bx.tcx();
-    let sig = tcx.normalize_erasing_late_bound_regions(
-        ty::TypingEnv::fully_monomorphized(),
-        callee_ty.fn_sig(tcx),
-    );
-    let arg_tys = sig.inputs();
-
     if name == sym::simd_select_bitmask {
         require_simd!(
-            arg_tys[1],
-            InvalidMonomorphization::SimdArgument { span, name, ty: arg_tys[1] }
+            args[1].layout.ty,
+            InvalidMonomorphization::SimdArgument { span, name, ty: args[1].layout.ty }
         );
-        let (len, _) = arg_tys[1].simd_size_and_type(bx.tcx());
+        let (len, _) = args[1].layout.ty.simd_size_and_type(bx.tcx());
 
         let expected_int_bits = (len.max(8) - 1).next_power_of_two();
         let expected_bytes = len / 8 + ((len % 8 > 0) as u64);
 
-        let mask_ty = arg_tys[0];
+        let mask_ty = args[0].layout.ty;
         let mut mask = match *mask_ty.kind() {
             ty::Int(i) if i.bit_width() == Some(expected_int_bits) => args[0].immediate(),
             ty::Uint(i) if i.bit_width() == Some(expected_int_bits) => args[0].immediate(),
@@ -121,8 +113,11 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
     }
 
     // every intrinsic below takes a SIMD vector as its first argument
-    require_simd!(arg_tys[0], InvalidMonomorphization::SimdInput { span, name, ty: arg_tys[0] });
-    let in_ty = arg_tys[0];
+    require_simd!(
+        args[0].layout.ty,
+        InvalidMonomorphization::SimdInput { span, name, ty: args[0].layout.ty }
+    );
+    let in_ty = args[0].layout.ty;
 
     let comparison = match name {
         sym::simd_eq => Some(BinOp::Eq),
@@ -134,7 +129,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         _ => None,
     };
 
-    let (in_len, in_elem) = arg_tys[0].simd_size_and_type(bx.tcx());
+    let (in_len, in_elem) = args[0].layout.ty.simd_size_and_type(bx.tcx());
     if let Some(cmp_op) = comparison {
         require_simd!(ret_ty, InvalidMonomorphization::SimdReturn { span, name, ty: ret_ty });
 
@@ -401,13 +396,13 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
     #[cfg(feature = "master")]
     if name == sym::simd_insert || name == sym::simd_insert_dyn {
         require!(
-            in_elem == arg_tys[2],
+            in_elem == args[2].layout.ty,
             InvalidMonomorphization::InsertedType {
                 span,
                 name,
                 in_elem,
                 in_ty,
-                out_ty: arg_tys[2]
+                out_ty: args[2].layout.ty
             }
         );
 
@@ -439,10 +434,10 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         let m_elem_ty = in_elem;
         let m_len = in_len;
         require_simd!(
-            arg_tys[1],
-            InvalidMonomorphization::SimdArgument { span, name, ty: arg_tys[1] }
+            args[1].layout.ty,
+            InvalidMonomorphization::SimdArgument { span, name, ty: args[1].layout.ty }
         );
-        let (v_len, _) = arg_tys[1].simd_size_and_type(bx.tcx());
+        let (v_len, _) = args[1].layout.ty.simd_size_and_type(bx.tcx());
         require!(
             m_len == v_len,
             InvalidMonomorphization::MismatchedLengths { span, name, m_len, v_len }
@@ -911,18 +906,18 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         // All types must be simd vector types
         require_simd!(in_ty, InvalidMonomorphization::SimdFirst { span, name, ty: in_ty });
         require_simd!(
-            arg_tys[1],
-            InvalidMonomorphization::SimdSecond { span, name, ty: arg_tys[1] }
+            args[1].layout.ty,
+            InvalidMonomorphization::SimdSecond { span, name, ty: args[1].layout.ty }
         );
         require_simd!(
-            arg_tys[2],
-            InvalidMonomorphization::SimdThird { span, name, ty: arg_tys[2] }
+            args[2].layout.ty,
+            InvalidMonomorphization::SimdThird { span, name, ty: args[2].layout.ty }
         );
         require_simd!(ret_ty, InvalidMonomorphization::SimdReturn { span, name, ty: ret_ty });
 
         // Of the same length:
-        let (out_len, _) = arg_tys[1].simd_size_and_type(bx.tcx());
-        let (out_len2, _) = arg_tys[2].simd_size_and_type(bx.tcx());
+        let (out_len, _) = args[1].layout.ty.simd_size_and_type(bx.tcx());
+        let (out_len2, _) = args[2].layout.ty.simd_size_and_type(bx.tcx());
         require!(
             in_len == out_len,
             InvalidMonomorphization::SecondArgumentLength {
@@ -930,7 +925,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                 name,
                 in_len,
                 in_ty,
-                arg_ty: arg_tys[1],
+                arg_ty: args[1].layout.ty,
                 out_len
             }
         );
@@ -941,7 +936,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                 name,
                 in_len,
                 in_ty,
-                arg_ty: arg_tys[2],
+                arg_ty: args[2].layout.ty,
                 out_len: out_len2
             }
         );
@@ -970,8 +965,8 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
 
         // The second argument must be a simd vector with an element type that's a pointer
         // to the element type of the first argument
-        let (_, element_ty0) = arg_tys[0].simd_size_and_type(bx.tcx());
-        let (_, element_ty1) = arg_tys[1].simd_size_and_type(bx.tcx());
+        let (_, element_ty0) = args[0].layout.ty.simd_size_and_type(bx.tcx());
+        let (_, element_ty1) = args[1].layout.ty.simd_size_and_type(bx.tcx());
         let (pointer_count, underlying_ty) = match *element_ty1.kind() {
             ty::RawPtr(p_ty, _) if p_ty == in_elem => {
                 (ptr_count(element_ty1), non_ptr(element_ty1))
@@ -983,7 +978,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                         span,
                         name,
                         expected_element: element_ty1,
-                        second_arg: arg_tys[1],
+                        second_arg: args[1].layout.ty,
                         in_elem,
                         in_ty,
                         mutability: ExpectedPointerMutability::Not,
@@ -998,7 +993,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
 
         // The element type of the third argument must be an integer type of any width:
         // TODO: also support unsigned integers.
-        let (_, element_ty2) = arg_tys[2].simd_size_and_type(bx.tcx());
+        let (_, element_ty2) = args[2].layout.ty.simd_size_and_type(bx.tcx());
         match *element_ty2.kind() {
             ty::Int(_) => (),
             _ => {
@@ -1030,17 +1025,17 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         // All types must be simd vector types
         require_simd!(in_ty, InvalidMonomorphization::SimdFirst { span, name, ty: in_ty });
         require_simd!(
-            arg_tys[1],
-            InvalidMonomorphization::SimdSecond { span, name, ty: arg_tys[1] }
+            args[1].layout.ty,
+            InvalidMonomorphization::SimdSecond { span, name, ty: args[1].layout.ty }
         );
         require_simd!(
-            arg_tys[2],
-            InvalidMonomorphization::SimdThird { span, name, ty: arg_tys[2] }
+            args[2].layout.ty,
+            InvalidMonomorphization::SimdThird { span, name, ty: args[2].layout.ty }
         );
 
         // Of the same length:
-        let (element_len1, _) = arg_tys[1].simd_size_and_type(bx.tcx());
-        let (element_len2, _) = arg_tys[2].simd_size_and_type(bx.tcx());
+        let (element_len1, _) = args[1].layout.ty.simd_size_and_type(bx.tcx());
+        let (element_len2, _) = args[2].layout.ty.simd_size_and_type(bx.tcx());
         require!(
             in_len == element_len1,
             InvalidMonomorphization::SecondArgumentLength {
@@ -1048,7 +1043,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                 name,
                 in_len,
                 in_ty,
-                arg_ty: arg_tys[1],
+                arg_ty: args[1].layout.ty,
                 out_len: element_len1
             }
         );
@@ -1059,7 +1054,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                 name,
                 in_len,
                 in_ty,
-                arg_ty: arg_tys[2],
+                arg_ty: args[2].layout.ty,
                 out_len: element_len2
             }
         );
@@ -1082,9 +1077,9 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
 
         // The second argument must be a simd vector with an element type that's a pointer
         // to the element type of the first argument
-        let (_, element_ty0) = arg_tys[0].simd_size_and_type(bx.tcx());
-        let (_, element_ty1) = arg_tys[1].simd_size_and_type(bx.tcx());
-        let (_, element_ty2) = arg_tys[2].simd_size_and_type(bx.tcx());
+        let (_, element_ty0) = args[0].layout.ty.simd_size_and_type(bx.tcx());
+        let (_, element_ty1) = args[1].layout.ty.simd_size_and_type(bx.tcx());
+        let (_, element_ty2) = args[2].layout.ty.simd_size_and_type(bx.tcx());
         let (pointer_count, underlying_ty) = match *element_ty1.kind() {
             ty::RawPtr(p_ty, mutbl) if p_ty == in_elem && mutbl == hir::Mutability::Mut => {
                 (ptr_count(element_ty1), non_ptr(element_ty1))
@@ -1096,7 +1091,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                         span,
                         name,
                         expected_element: element_ty1,
-                        second_arg: arg_tys[1],
+                        second_arg: args[1].layout.ty,
                         in_elem,
                         in_ty,
                         mutability: ExpectedPointerMutability::Mut,
@@ -1194,8 +1189,8 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                 return_error!(InvalidMonomorphization::ExpectedVectorElementType {
                     span,
                     name,
-                    expected_element: arg_tys[0].simd_size_and_type(bx.tcx()).1,
-                    vector_type: arg_tys[0],
+                    expected_element: args[0].layout.ty.simd_size_and_type(bx.tcx()).1,
+                    vector_type: args[0].layout.ty,
                 });
             }
         };
diff --git a/compiler/rustc_codegen_llvm/src/intrinsic.rs b/compiler/rustc_codegen_llvm/src/intrinsic.rs
index e8629aeebb95a..989752eb78ea4 100644
--- a/compiler/rustc_codegen_llvm/src/intrinsic.rs
+++ b/compiler/rustc_codegen_llvm/src/intrinsic.rs
@@ -169,19 +169,9 @@ impl<'ll, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
         span: Span,
     ) -> Result<(), ty::Instance<'tcx>> {
         let tcx = self.tcx;
-        let callee_ty = instance.ty(tcx, self.typing_env());
 
-        let ty::FnDef(def_id, fn_args) = *callee_ty.kind() else {
-            bug!("expected fn item type, found {}", callee_ty);
-        };
-
-        let sig = callee_ty.fn_sig(tcx);
-        let sig = tcx.normalize_erasing_late_bound_regions(self.typing_env(), sig);
-        let arg_tys = sig.inputs();
-        let ret_ty = sig.output();
-        let name = tcx.item_name(def_id);
-
-        let llret_ty = self.layout_of(ret_ty).llvm_type(self);
+        let name = tcx.item_name(instance.def_id());
+        let fn_args = instance.args;
 
         let simple = get_simple_intrinsic(self, name);
         let llval = match name {
@@ -265,22 +255,22 @@ impl<'ll, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
                     BackendRepr::Scalar(scalar) => {
                         match scalar.primitive() {
                             Primitive::Int(..) => {
-                                if self.cx().size_of(ret_ty).bytes() < 4 {
+                                if self.cx().size_of(result.layout.ty).bytes() < 4 {
                                     // `va_arg` should not be called on an integer type
                                     // less than 4 bytes in length. If it is, promote
                                     // the integer to an `i32` and truncate the result
                                     // back to the smaller type.
                                     let promoted_result = emit_va_arg(self, args[0], tcx.types.i32);
-                                    self.trunc(promoted_result, llret_ty)
+                                    self.trunc(promoted_result, result.layout.llvm_type(self))
                                 } else {
-                                    emit_va_arg(self, args[0], ret_ty)
+                                    emit_va_arg(self, args[0], result.layout.ty)
                                 }
                             }
                             Primitive::Float(Float::F16) => {
                                 bug!("the va_arg intrinsic does not work with `f16`")
                             }
                             Primitive::Float(Float::F64) | Primitive::Pointer(_) => {
-                                emit_va_arg(self, args[0], ret_ty)
+                                emit_va_arg(self, args[0], result.layout.ty)
                             }
                             // `va_arg` should never be used with the return type f32.
                             Primitive::Float(Float::F32) => {
@@ -384,7 +374,7 @@ impl<'ll, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
             | sym::rotate_right
             | sym::saturating_add
             | sym::saturating_sub => {
-                let ty = arg_tys[0];
+                let ty = args[0].layout.ty;
                 if !ty.is_integral() {
                     tcx.dcx().emit_err(InvalidMonomorphization::BasicIntegerType {
                         span,
@@ -403,26 +393,26 @@ impl<'ll, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
                             &[args[0].immediate(), y],
                         );
 
-                        self.intcast(ret, llret_ty, false)
+                        self.intcast(ret, result.layout.llvm_type(self), false)
                     }
                     sym::ctlz_nonzero => {
                         let y = self.const_bool(true);
                         let llvm_name = &format!("llvm.ctlz.i{width}");
                         let ret = self.call_intrinsic(llvm_name, &[args[0].immediate(), y]);
-                        self.intcast(ret, llret_ty, false)
+                        self.intcast(ret, result.layout.llvm_type(self), false)
                     }
                     sym::cttz_nonzero => {
                         let y = self.const_bool(true);
                         let llvm_name = &format!("llvm.cttz.i{width}");
                         let ret = self.call_intrinsic(llvm_name, &[args[0].immediate(), y]);
-                        self.intcast(ret, llret_ty, false)
+                        self.intcast(ret, result.layout.llvm_type(self), false)
                     }
                     sym::ctpop => {
                         let ret = self.call_intrinsic(
                             &format!("llvm.ctpop.i{width}"),
                             &[args[0].immediate()],
                         );
-                        self.intcast(ret, llret_ty, false)
+                        self.intcast(ret, result.layout.llvm_type(self), false)
                     }
                     sym::bswap => {
                         if width == 8 {
@@ -554,16 +544,16 @@ impl<'ll, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
                 // Unpack non-power-of-2 #[repr(packed, simd)] arguments.
                 // This gives them the expected layout of a regular #[repr(simd)] vector.
                 let mut loaded_args = Vec::new();
-                for (ty, arg) in arg_tys.iter().zip(args) {
+                for arg in args {
                     loaded_args.push(
                         // #[repr(packed, simd)] vectors are passed like arrays (as references,
                         // with reduced alignment and no padding) rather than as immediates.
                         // We can use a vector load to fix the layout and turn the argument
                         // into an immediate.
-                        if ty.is_simd()
+                        if arg.layout.ty.is_simd()
                             && let OperandValue::Ref(place) = arg.val
                         {
-                            let (size, elem_ty) = ty.simd_size_and_type(self.tcx());
+                            let (size, elem_ty) = arg.layout.ty.simd_size_and_type(self.tcx());
                             let elem_ll_ty = match elem_ty.kind() {
                                 ty::Float(f) => self.type_float_from_ty(*f),
                                 ty::Int(i) => self.type_int_from_ty(*i),
@@ -580,10 +570,10 @@ impl<'ll, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
                     );
                 }
 
-                let llret_ty = if ret_ty.is_simd()
-                    && let BackendRepr::Memory { .. } = self.layout_of(ret_ty).layout.backend_repr
+                let llret_ty = if result.layout.ty.is_simd()
+                    && let BackendRepr::Memory { .. } = result.layout.backend_repr
                 {
-                    let (size, elem_ty) = ret_ty.simd_size_and_type(self.tcx());
+                    let (size, elem_ty) = result.layout.ty.simd_size_and_type(self.tcx());
                     let elem_ll_ty = match elem_ty.kind() {
                         ty::Float(f) => self.type_float_from_ty(*f),
                         ty::Int(i) => self.type_int_from_ty(*i),
@@ -593,16 +583,15 @@ impl<'ll, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
                     };
                     self.type_vector(elem_ll_ty, size)
                 } else {
-                    llret_ty
+                    result.layout.llvm_type(self)
                 };
 
                 match generic_simd_intrinsic(
                     self,
                     name,
-                    callee_ty,
                     fn_args,
                     &loaded_args,
-                    ret_ty,
+                    result.layout.ty,
                     llret_ty,
                     span,
                 ) {
@@ -621,9 +610,8 @@ impl<'ll, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
         };
 
         if result.layout.ty.is_bool() {
-            OperandRef::from_immediate_or_packed_pair(self, llval, result.layout)
-                .val
-                .store(self, result);
+            let val = self.from_immediate(llval);
+            self.store_to_place(val, result.val);
         } else if !result.layout.ty.is_unit() {
             self.store_to_place(llval, result.val);
         }
@@ -1151,7 +1139,6 @@ fn get_rust_try_fn<'a, 'll, 'tcx>(
 fn generic_simd_intrinsic<'ll, 'tcx>(
     bx: &mut Builder<'_, 'll, 'tcx>,
     name: Symbol,
-    callee_ty: Ty<'tcx>,
     fn_args: GenericArgsRef<'tcx>,
     args: &[OperandRef<'tcx, &'ll Value>],
     ret_ty: Ty<'tcx>,
@@ -1222,26 +1209,22 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
         bx.trunc(i_xn_msb, bx.type_vector(bx.type_i1(), in_len))
     }
 
-    let tcx = bx.tcx();
-    let sig = tcx.normalize_erasing_late_bound_regions(bx.typing_env(), callee_ty.fn_sig(tcx));
-    let arg_tys = sig.inputs();
-
     // Sanity-check: all vector arguments must be immediates.
     if cfg!(debug_assertions) {
-        for (ty, arg) in arg_tys.iter().zip(args) {
-            if ty.is_simd() {
+        for arg in args {
+            if arg.layout.ty.is_simd() {
                 assert_matches!(arg.val, OperandValue::Immediate(_));
             }
         }
     }
 
     if name == sym::simd_select_bitmask {
-        let (len, _) = require_simd!(arg_tys[1], SimdArgument);
+        let (len, _) = require_simd!(args[1].layout.ty, SimdArgument);
 
         let expected_int_bits = len.max(8).next_power_of_two();
         let expected_bytes = len.div_ceil(8);
 
-        let mask_ty = arg_tys[0];
+        let mask_ty = args[0].layout.ty;
         let mask = match mask_ty.kind() {
             ty::Int(i) if i.bit_width() == Some(expected_int_bits) => args[0].immediate(),
             ty::Uint(i) if i.bit_width() == Some(expected_int_bits) => args[0].immediate(),
@@ -1275,8 +1258,8 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
     }
 
     // every intrinsic below takes a SIMD vector as its first argument
-    let (in_len, in_elem) = require_simd!(arg_tys[0], SimdInput);
-    let in_ty = arg_tys[0];
+    let (in_len, in_elem) = require_simd!(args[0].layout.ty, SimdInput);
+    let in_ty = args[0].layout.ty;
 
     let comparison = match name {
         sym::simd_eq => Some(BinOp::Eq),
@@ -1407,13 +1390,13 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
 
     if name == sym::simd_insert || name == sym::simd_insert_dyn {
         require!(
-            in_elem == arg_tys[2],
+            in_elem == args[2].layout.ty,
             InvalidMonomorphization::InsertedType {
                 span,
                 name,
                 in_elem,
                 in_ty,
-                out_ty: arg_tys[2]
+                out_ty: args[2].layout.ty
             }
         );
 
@@ -1464,7 +1447,7 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
     if name == sym::simd_select {
         let m_elem_ty = in_elem;
         let m_len = in_len;
-        let (v_len, _) = require_simd!(arg_tys[1], SimdArgument);
+        let (v_len, _) = require_simd!(args[1].layout.ty, SimdArgument);
         require!(
             m_len == v_len,
             InvalidMonomorphization::MismatchedLengths { span, name, m_len, v_len }
@@ -1665,9 +1648,9 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
         // The second argument must be a simd vector with an element type that's a pointer
         // to the element type of the first argument
         let (_, element_ty0) = require_simd!(in_ty, SimdFirst);
-        let (out_len, element_ty1) = require_simd!(arg_tys[1], SimdSecond);
+        let (out_len, element_ty1) = require_simd!(args[1].layout.ty, SimdSecond);
         // The element type of the third argument must be a signed integer type of any width:
-        let (out_len2, element_ty2) = require_simd!(arg_tys[2], SimdThird);
+        let (out_len2, element_ty2) = require_simd!(args[2].layout.ty, SimdThird);
         require_simd!(ret_ty, SimdReturn);
 
         // Of the same length:
@@ -1678,7 +1661,7 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
                 name,
                 in_len,
                 in_ty,
-                arg_ty: arg_tys[1],
+                arg_ty: args[1].layout.ty,
                 out_len
             }
         );
@@ -1689,7 +1672,7 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
                 name,
                 in_len,
                 in_ty,
-                arg_ty: arg_tys[2],
+                arg_ty: args[2].layout.ty,
                 out_len: out_len2
             }
         );
@@ -1709,7 +1692,7 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
                 span,
                 name,
                 expected_element: element_ty1,
-                second_arg: arg_tys[1],
+                second_arg: args[1].layout.ty,
                 in_elem,
                 in_ty,
                 mutability: ExpectedPointerMutability::Not,
@@ -1770,10 +1753,10 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
         let (mask_len, mask_elem) = (in_len, in_elem);
 
         // The second argument must be a pointer matching the element type
-        let pointer_ty = arg_tys[1];
+        let pointer_ty = args[1].layout.ty;
 
         // The last argument is a passthrough vector providing values for disabled lanes
-        let values_ty = arg_tys[2];
+        let values_ty = args[2].layout.ty;
         let (values_len, values_elem) = require_simd!(values_ty, SimdThird);
 
         require_simd!(ret_ty, SimdReturn);
@@ -1861,10 +1844,10 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
         let (mask_len, mask_elem) = (in_len, in_elem);
 
         // The second argument must be a pointer matching the element type
-        let pointer_ty = arg_tys[1];
+        let pointer_ty = args[1].layout.ty;
 
         // The last argument specifies the values to store to memory
-        let values_ty = arg_tys[2];
+        let values_ty = args[2].layout.ty;
         let (values_len, values_elem) = require_simd!(values_ty, SimdThird);
 
         // Of the same length:
@@ -1944,8 +1927,8 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
         // The second argument must be a simd vector with an element type that's a pointer
         // to the element type of the first argument
         let (_, element_ty0) = require_simd!(in_ty, SimdFirst);
-        let (element_len1, element_ty1) = require_simd!(arg_tys[1], SimdSecond);
-        let (element_len2, element_ty2) = require_simd!(arg_tys[2], SimdThird);
+        let (element_len1, element_ty1) = require_simd!(args[1].layout.ty, SimdSecond);
+        let (element_len2, element_ty2) = require_simd!(args[2].layout.ty, SimdThird);
 
         // Of the same length:
         require!(
@@ -1955,7 +1938,7 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
                 name,
                 in_len,
                 in_ty,
-                arg_ty: arg_tys[1],
+                arg_ty: args[1].layout.ty,
                 out_len: element_len1
             }
         );
@@ -1966,7 +1949,7 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
                 name,
                 in_len,
                 in_ty,
-                arg_ty: arg_tys[2],
+                arg_ty: args[2].layout.ty,
                 out_len: element_len2
             }
         );
@@ -1981,7 +1964,7 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
                 span,
                 name,
                 expected_element: element_ty1,
-                second_arg: arg_tys[1],
+                second_arg: args[1].layout.ty,
                 in_elem,
                 in_ty,
                 mutability: ExpectedPointerMutability::Mut,
@@ -2503,7 +2486,7 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
         let ptrs = args[0].immediate();
         // The second argument must be a ptr-sized integer.
         // (We don't care about the signedness, this is wrapping anyway.)
-        let (_offsets_len, offsets_elem) = arg_tys[1].simd_size_and_type(bx.tcx());
+        let (_offsets_len, offsets_elem) = args[1].layout.ty.simd_size_and_type(bx.tcx());
         if !matches!(offsets_elem.kind(), ty::Int(ty::IntTy::Isize) | ty::Uint(ty::UintTy::Usize)) {
             span_bug!(
                 span,
@@ -2527,8 +2510,8 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
                 return_error!(InvalidMonomorphization::ExpectedVectorElementType {
                     span,
                     name,
-                    expected_element: arg_tys[0].simd_size_and_type(bx.tcx()).1,
-                    vector_type: arg_tys[0]
+                    expected_element: args[0].layout.ty.simd_size_and_type(bx.tcx()).1,
+                    vector_type: args[0].layout.ty
                 });
             }
         };
diff --git a/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs b/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
index a79d67bb6cdcc..8c6f52084c2e4 100644
--- a/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
@@ -1,7 +1,7 @@
 use rustc_abi::WrappingRange;
+use rustc_middle::bug;
 use rustc_middle::mir::SourceInfo;
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_middle::{bug, span_bug};
 use rustc_session::config::OptLevel;
 use rustc_span::sym;
 
@@ -60,18 +60,10 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         source_info: SourceInfo,
     ) -> Result<(), ty::Instance<'tcx>> {
         let span = source_info.span;
-        let callee_ty = instance.ty(bx.tcx(), bx.typing_env());
 
-        let ty::FnDef(def_id, fn_args) = *callee_ty.kind() else {
-            span_bug!(span, "expected fn item type, found {}", callee_ty);
-        };
-
-        let sig = callee_ty.fn_sig(bx.tcx());
-        let sig = bx.tcx().normalize_erasing_late_bound_regions(bx.typing_env(), sig);
-        let arg_tys = sig.inputs();
-        let ret_ty = sig.output();
-        let name = bx.tcx().item_name(def_id);
+        let name = bx.tcx().item_name(instance.def_id());
         let name_str = name.as_str();
+        let fn_args = instance.args;
 
         // If we're swapping something that's *not* an `OperandValue::Ref`,
         // then we can do it directly and avoid the alloca.
@@ -97,13 +89,10 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             }
         }
 
-        let llret_ty = bx.backend_type(bx.layout_of(ret_ty));
-
         let ret_llval = |bx: &mut Bx, llval| {
             if result.layout.ty.is_bool() {
-                OperandRef::from_immediate_or_packed_pair(bx, llval, result.layout)
-                    .val
-                    .store(bx, result);
+                let val = bx.from_immediate(llval);
+                bx.store_to_place(val, result.val);
             } else if !result.layout.ty.is_unit() {
                 bx.store_to_place(llval, result.val);
             }
@@ -143,7 +132,11 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     sym::vtable_align => ty::COMMON_VTABLE_ENTRIES_ALIGN,
                     _ => bug!(),
                 };
-                let value = meth::VirtualIndex::from_index(idx).get_usize(bx, vtable, callee_ty);
+                let value = meth::VirtualIndex::from_index(idx).get_usize(
+                    bx,
+                    vtable,
+                    instance.ty(bx.tcx(), bx.typing_env()),
+                );
                 match name {
                     // Size is always <= isize::MAX.
                     sym::vtable_size => {
@@ -164,7 +157,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             | sym::type_name
             | sym::variant_count => {
                 let value = bx.tcx().const_eval_instance(bx.typing_env(), instance, span).unwrap();
-                OperandRef::from_const(bx, value, ret_ty).immediate_or_packed_pair(bx)
+                OperandRef::from_const(bx, value, result.layout.ty).immediate_or_packed_pair(bx)
             }
             sym::arith_offset => {
                 let ty = fn_args.type_at(0);
@@ -248,7 +241,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 bx.or_disjoint(a, b)
             }
             sym::exact_div => {
-                let ty = arg_tys[0];
+                let ty = args[0].layout.ty;
                 match int_type_width_signed(ty, bx.tcx()) {
                     Some((_width, signed)) => {
                         if signed {
@@ -268,7 +261,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 }
             }
             sym::fadd_fast | sym::fsub_fast | sym::fmul_fast | sym::fdiv_fast | sym::frem_fast => {
-                match float_type_width(arg_tys[0]) {
+                match float_type_width(args[0].layout.ty) {
                     Some(_width) => match name {
                         sym::fadd_fast => bx.fadd_fast(args[0].immediate(), args[1].immediate()),
                         sym::fsub_fast => bx.fsub_fast(args[0].immediate(), args[1].immediate()),
@@ -281,7 +274,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                         bx.tcx().dcx().emit_err(InvalidMonomorphization::BasicFloatType {
                             span,
                             name,
-                            ty: arg_tys[0],
+                            ty: args[0].layout.ty,
                         });
                         return Ok(());
                     }
@@ -291,7 +284,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             | sym::fsub_algebraic
             | sym::fmul_algebraic
             | sym::fdiv_algebraic
-            | sym::frem_algebraic => match float_type_width(arg_tys[0]) {
+            | sym::frem_algebraic => match float_type_width(args[0].layout.ty) {
                 Some(_width) => match name {
                     sym::fadd_algebraic => {
                         bx.fadd_algebraic(args[0].immediate(), args[1].immediate())
@@ -314,31 +307,32 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     bx.tcx().dcx().emit_err(InvalidMonomorphization::BasicFloatType {
                         span,
                         name,
-                        ty: arg_tys[0],
+                        ty: args[0].layout.ty,
                     });
                     return Ok(());
                 }
             },
 
             sym::float_to_int_unchecked => {
-                if float_type_width(arg_tys[0]).is_none() {
+                if float_type_width(args[0].layout.ty).is_none() {
                     bx.tcx().dcx().emit_err(InvalidMonomorphization::FloatToIntUnchecked {
                         span,
-                        ty: arg_tys[0],
+                        ty: args[0].layout.ty,
                     });
                     return Ok(());
                 }
-                let Some((_width, signed)) = int_type_width_signed(ret_ty, bx.tcx()) else {
+                let Some((_width, signed)) = int_type_width_signed(result.layout.ty, bx.tcx())
+                else {
                     bx.tcx().dcx().emit_err(InvalidMonomorphization::FloatToIntUnchecked {
                         span,
-                        ty: ret_ty,
+                        ty: result.layout.ty,
                     });
                     return Ok(());
                 };
                 if signed {
-                    bx.fptosi(args[0].immediate(), llret_ty)
+                    bx.fptosi(args[0].immediate(), bx.backend_type(result.layout))
                 } else {
-                    bx.fptoui(args[0].immediate(), llret_ty)
+                    bx.fptoui(args[0].immediate(), bx.backend_type(result.layout))
                 }
             }