Don't call intrinsics in 3d dim/idx functions.

Instead call the Rust functions that have the range constraints. That
way the 3d version get the same range constraints as the 1d versions. It
also avoids the need for some `unsafe` blocks.

Author: nnethercote

crates/cuda_std/src/thread.rs

@@ -193,54 +193,46 @@ pub fn grid_dim_z() -> u32 {
 #[gpu_only]
 #[inline(always)]
 pub fn thread_idx() -> UVec3 {
-    unsafe {
-        UVec3::new(
-            __nvvm_thread_idx_x(),
-            __nvvm_thread_idx_y(),
-            __nvvm_thread_idx_z(),
-        )
-    }
+    UVec3::new(
+        thread_idx_x(),
+        thread_idx_y(),
+        thread_idx_z(),
+    )
 }
 
 /// Gets the 3d index of the block that the thread currently executing the kernel is located in.
 #[gpu_only]
 #[inline(always)]
 pub fn block_idx() -> UVec3 {
-    unsafe {
-        UVec3::new(
-            __nvvm_block_idx_x(),
-            __nvvm_block_idx_y(),
-            __nvvm_block_idx_z(),
-        )
-    }
+    UVec3::new(
+        block_idx_x(),
+        block_idx_y(),
+        block_idx_z(),
+    )
 }
 
 /// Gets the 3d layout of the thread blocks executing this kernel. In other words,
 /// how many threads exist in each thread block in every direction.
 #[gpu_only]
 #[inline(always)]
 pub fn block_dim() -> UVec3 {
-    unsafe {
-        UVec3::new(
-            __nvvm_block_dim_x(),
-            __nvvm_block_dim_y(),
-            __nvvm_block_dim_z(),
-        )
-    }
+    UVec3::new(
+        block_dim_x(),
+        block_dim_y(),
+        block_dim_z(),
+    )
 }
 
 /// Gets the 3d layout of the block grids executing this kernel. In other words,
 /// how many thread blocks exist in each grid in every direction.
 #[gpu_only]
 #[inline(always)]
 pub fn grid_dim() -> UVec3 {
-    unsafe {
-        UVec3::new(
-            __nvvm_grid_dim_x(),
-            __nvvm_grid_dim_y(),
-            __nvvm_grid_dim_z(),
-        )
-    }
+    UVec3::new(
+        grid_dim_x(),
+        grid_dim_y(),
+        grid_dim_z(),
+    )
 }
 
 /// Gets the overall thread index, accounting for 1d/2d/3d block/grid dimensions. This