Auto merge of #114156 - calebzulawski:simd-bswap, r=compiler-errors

Add simd_bswap, simd_bitreverse, simd_ctlz, and simd_cttz intrinsics

cc `@workingjubilee`

1 files changed, 47 insertions, 0 deletions

diff --git a/compiler/rustc_codegen_llvm/src/intrinsic.rs b/compiler/rustc_codegen_llvm/src/intrinsic.rs
index 6df1b708ccd..623c08ce86b 100644
--- a/compiler/rustc_codegen_llvm/src/intrinsic.rs
+++ b/compiler/rustc_codegen_llvm/src/intrinsic.rs
@@ -2074,6 +2074,53 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
         simd_neg: Int => neg, Float => fneg;
     }
 
+    // Unary integer intrinsics
+    if matches!(name, sym::simd_bswap | sym::simd_bitreverse | sym::simd_ctlz | sym::simd_cttz) {
+        let vec_ty = bx.cx.type_vector(
+            match *in_elem.kind() {
+                ty::Int(i) => bx.cx.type_int_from_ty(i),
+                ty::Uint(i) => bx.cx.type_uint_from_ty(i),
+                _ => return_error!(InvalidMonomorphization::UnsupportedOperation {
+                    span,
+                    name,
+                    in_ty,
+                    in_elem
+                }),
+            },
+            in_len as u64,
+        );
+        let intrinsic_name = match name {
+            sym::simd_bswap => "bswap",
+            sym::simd_bitreverse => "bitreverse",
+            sym::simd_ctlz => "ctlz",
+            sym::simd_cttz => "cttz",
+            _ => unreachable!(),
+        };
+        let llvm_intrinsic = &format!(
+            "llvm.{}.v{}i{}",
+            intrinsic_name,
+            in_len,
+            in_elem.int_size_and_signed(bx.tcx()).0.bits(),
+        );
+
+        return Ok(if matches!(name, sym::simd_ctlz | sym::simd_cttz) {
+            let fn_ty = bx.type_func(&[vec_ty, bx.type_i1()], vec_ty);
+            let f = bx.declare_cfn(llvm_intrinsic, llvm::UnnamedAddr::No, fn_ty);
+            bx.call(
+                fn_ty,
+                None,
+                None,
+                f,
+                &[args[0].immediate(), bx.const_int(bx.type_i1(), 0)],
+                None,
+            )
+        } else {
+            let fn_ty = bx.type_func(&[vec_ty], vec_ty);
+            let f = bx.declare_cfn(llvm_intrinsic, llvm::UnnamedAddr::No, fn_ty);
+            bx.call(fn_ty, None, None, f, &[args[0].immediate()], None)
+        });
+    }
+
     if name == sym::simd_arith_offset {
         // This also checks that the first operand is a ptr type.
         let pointee = in_elem.builtin_deref(true).unwrap_or_else(|| {