glslang-16.6.0

[Bruce Dubbs]

New minor version.

[Joe Locash]

## 16.6.0 2026-09-10

### New Extensions

* Implement `GL_EXT_cooperative_matrix_maintenance1`
* Implement `GL_EXT_optional_input_attachment_index`
* Implement `DebugEntryPoint` for `NonSemantic.Shader.DebugInfo` 102

### `SPV_KHR_abort` / `abortEXT`

* Require the first parameter of `abortEXT` to be a string literal, emit an error if it is not
* Require the first parameter of `printf` to be a string literal, emit an error if it is not
* Fix abort message struct layout for matrix, vector, and aggregate arguments
* Pack the abort message with scalar layout when the shader requests `GL_EXT_scalar_block_layout`
* Pack the abort message with scalar layout unconditionally so that consumers use one fixed set of rules
* Fix abort message type to use separate value and laid out types, removing invalid `ArrayStride` on constant types
* Fix `abort` to handle boolean and opaque types correctly

### API Changes

* Add access to the source entry point in the C API

### Bug Fixes

* Fix relaxed Vulkan access chain traversal for buffer references
* Fix 32-bit identity fillers used in 16-bit matrix constructors
* Fix out-of-bounds slot access for `atomic_uint` in `reserveResourceSlot`
* Fix out-of-bounds read when folding component-wise intrinsics on matrices
* Fix out-of-bounds dereference on undeclared ray tracing location
* Fix out-of-bounds read on empty `entryPoints` in `postProcessFeatures`
* Fix out-of-bounds read on short `coopMatPerElementNV` argument list
* Fix crash on empty struct initializers in cascading error mode
* Guard empty block member list in `getBlockSize`
* Validate argument count in `decomposeStructBufferMethods`
* Require constant scope and semantics operands in `memorySemanticsCheck`
* Fix string escaping in preprocessed output
* Fix `Aligned` decoration on `buffer_reference` swizzle-store read-modify-write load
* Fold bit-cast conversions as constant expressions
* Fold hyperbolic functions (`sinh`, `cosh`, `tanh`, `asinh`, `acosh`, `atanh`) as constant expressions
* Improve parsing of `#pragma STDGL`

### Performance

* Replace linear search with a hash table for composite and struct constant creation in the SPIR-V builder

Fixed at 1ec1bebd59.