feat(const_eval): impl. exp

CHANGELOG.md

@@ -71,6 +71,7 @@ Bottom level categories:
         - `countLeadingZeros`
         - `countOneBits`
         - `countTrailingZeros`
+        - `exp`
         - `floor`
 - Eager release of GPU resources comes from device.trackers. By @bradwerth in [#5075](https://github.com/gfx-rs/wgpu/pull/5075)
 - `wgpu-types`'s `trace` and `replay` features have been replaced by the `serde` feature. By @KirmesBude in [#5149](https://github.com/gfx-rs/wgpu/pull/5149)

naga/src/proc/constant_evaluator.rs

@@ -904,6 +904,9 @@ impl<'a> ConstantEvaluator<'a> {
                         .expect("bit count overflowed 32 bits, somehow!?")])
                 })
             }
+            crate::MathFunction::Exp => {
+                component_wise_float!(self, span, [arg], |e| { Ok([e.exp()]) })
+            }
             crate::MathFunction::Floor => {
                 component_wise_float!(self, span, [arg], |e| { Ok([e.floor()]) })
             }