From e0b87e4dd53c028e2db49fd8dc64e2f56d3548f8 Mon Sep 17 00:00:00 2001
From: Folkert de Vries <folkert@folkertdev.nl>
Date: Mon, 19 Jan 2026 15:44:11 +0100
Subject: [PATCH] `simd_splat`: custom error in gcc backend for invalid element
 type

---
 src/intrinsic/simd.rs | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/intrinsic/simd.rs b/src/intrinsic/simd.rs
index 0606639d1731..eab067a02b7b 100644
--- a/src/intrinsic/simd.rs
+++ b/src/intrinsic/simd.rs
@@ -121,9 +121,9 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         return Ok(bx.vector_select(vector_mask, arg1, args[2].immediate()));
     }
 
+    #[cfg(feature = "master")]
     if name == sym::simd_splat {
-        require_simd!(ret_ty, InvalidMonomorphization::SimdReturn { span, name, ty: ret_ty });
-        let (out_len, out_ty) = ret_ty.simd_size_and_type(bx.tcx());
+        let (out_len, out_ty) = require_simd2!(ret_ty, SimdReturn);
 
         require!(
             args[0].layout.ty == out_ty,
@@ -139,11 +139,18 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
         let elem_ty = vec_ty.get_element_type();
 
         // Cast pointer type to usize (GCC does not support pointer SIMD vectors).
-        let scalar = args[0].immediate();
-        let scalar = if scalar.get_type().unqualified() != elem_ty.unqualified() {
-            bx.ptrtoint(scalar, elem_ty)
+        let value = args[0];
+        let scalar = if value.layout.ty.is_numeric() {
+            value.immediate()
+        } else if value.layout.ty.is_raw_ptr() {
+            bx.ptrtoint(value.immediate(), elem_ty)
         } else {
-            scalar
+            return_error!(InvalidMonomorphization::UnsupportedOperation {
+                span,
+                name,
+                in_ty: ret_ty,
+                in_elem: value.layout.ty
+            });
         };
 
         let elements = vec![scalar; out_len as usize];