From 5549a45fd114b9467b8bf64a150b94426fa513d4 Mon Sep 17 00:00:00 2001
From: Eduard-Mihai Burtescu <eddyb@vectorware.com>
Date: Tue, 9 Sep 2025 11:40:02 +0300
Subject: [PATCH 1/2] builder: allow unsigned integers in `neg` and
 `exactsdiv`.

---
 crates/rustc_codegen_spirv/src/builder/builder_methods.rs | 8 ++++----
 examples/shaders/compute-shader/src/lib.rs                | 8 +++++++-
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/crates/rustc_codegen_spirv/src/builder/builder_methods.rs b/crates/rustc_codegen_spirv/src/builder/builder_methods.rs
index d86db1cbd00..c1f653c7052 100644
--- a/crates/rustc_codegen_spirv/src/builder/builder_methods.rs
+++ b/crates/rustc_codegen_spirv/src/builder/builder_methods.rs
@@ -1600,9 +1600,9 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
     // Same note and TODO as exactudiv
     simple_op! {
         exactsdiv,
-        sint: s_div,
+        int: s_div,
         fold_const {
-            sint(a, b) => a.checked_div(b)?;
+            int(a, b) => a.checked_div(b)?;
         }
     }
     simple_op! {fdiv, float: f_div}
@@ -1648,9 +1648,9 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
     }
     simple_uni_op! {
         neg,
-        sint: s_negate,
+        int: s_negate,
         fold_const {
-            sint(a) => a.checked_neg()?;
+            int(a) => a.checked_neg()?;
         }
     }
     simple_uni_op! {fneg, float: f_negate}
diff --git a/examples/shaders/compute-shader/src/lib.rs b/examples/shaders/compute-shader/src/lib.rs
index 16f91439004..c9408c2668a 100644
--- a/examples/shaders/compute-shader/src/lib.rs
+++ b/examples/shaders/compute-shader/src/lib.rs
@@ -46,6 +46,12 @@ pub fn main_cs(
     #[spirv(global_invocation_id)] id: UVec3,
     #[spirv(storage_buffer, descriptor_set = 0, binding = 0)] prime_indices: &mut [u32],
 ) {
-    let index = id.x as usize;
+    let index = id.x as usize
+        + core::mem::size_of_val(
+            const {
+                struct S<T: ?Sized>(T);
+                &S([]) as &S<[()]>
+            },
+        );
     prime_indices[index] = collatz(prime_indices[index]).unwrap_or(u32::MAX);
 }

From 7ff8561fdd071167309138c615a024596a398ce7 Mon Sep 17 00:00:00 2001
From: Eduard-Mihai Burtescu <eddyb@vectorware.com>
Date: Tue, 9 Sep 2025 11:40:02 +0300
Subject: [PATCH 2/2] constant: avoid div-by-0 due to ZST arrays/slices.

---
 crates/rustc_codegen_spirv/src/codegen_cx/constant.rs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/crates/rustc_codegen_spirv/src/codegen_cx/constant.rs b/crates/rustc_codegen_spirv/src/codegen_cx/constant.rs
index bf874130e83..5c850bff2b7 100644
--- a/crates/rustc_codegen_spirv/src/codegen_cx/constant.rs
+++ b/crates/rustc_codegen_spirv/src/codegen_cx/constant.rs
@@ -573,9 +573,10 @@ impl<'tcx> CodegenCx<'tcx> {
                     SpirvType::Array { count, .. } => {
                         u64::try_from(self.builder.lookup_const_scalar(count).unwrap()).unwrap()
                     }
-                    SpirvType::RuntimeArray { .. } => {
-                        (alloc.inner().size() - offset).bytes() / stride.bytes()
-                    }
+                    SpirvType::RuntimeArray { .. } => (alloc.inner().size() - offset)
+                        .bytes()
+                        .checked_div(stride.bytes())
+                        .unwrap_or(0),
                     _ => unreachable!(),
                 };