Update README (#3047)
* This project supports SPIR-V 1.5
* Update description of the optimizer
diff --git a/README.md b/README.md
index 9ec146a..5714976 100644
--- a/README.md
+++ b/README.md
@@ -49,9 +49,11 @@
### Assembler, binary parser, and disassembler
-* Support for SPIR-V 1.0, 1.1, 1.2, and 1.3
+* Support for SPIR-V 1.0, through 1.5
* Based on SPIR-V syntax described by JSON grammar files in the
[SPIRV-Headers](https://github.com/KhronosGroup/SPIRV-Headers) repository.
+ * Usually, support for a new version of SPIR-V is ready within days after
+ publication.
* Support for extended instruction sets:
* GLSL std450 version 1.0 Rev 3
* OpenCL version 1.0 Rev 2
@@ -88,14 +90,22 @@
### Optimizer
-*Note:* The optimizer is still under development.
+The optimizer is a collection of code transforms, or "passes".
+Transforms are written for a diverse set of reasons:
-Currently supported optimizations:
-* General
+* To restructure, simplify, or normalize the code for further processing.
+* To eliminate undesirable code.
+* To improve code quality in some metric such as size or performance.
+ **Note**: These transforms are not guaranteed to actually improve any
+ given metric. Users should always measure results for their own situation.
+
+As of this writing, there are 67 transforms including examples such as:
+* Simplification
* Strip debug info
+ * Strip reflection info
* Specialization Constants
* Set spec constant default value
- * Freeze spec constant
+ * Freeze spec constant to default value
* Fold `OpSpecConstantOp` and `OpSpecConstantComposite`
* Unify constants
* Eliminate dead constant
@@ -112,6 +122,29 @@
* Eliminate common uniform loads
* Remove duplicates: Capabilities, extended instruction imports, types, and
decorations.
+* Normalization
+ * Compact IDs
+ * CFG cleanup
+ * Flatten decorations
+ * Merge returns
+ * Convert AMD-specific instructions to KHR instructions
+* Code improvement
+ * Conditional constant propagation
+ * If-conversion
+ * Loop fission
+ * Loop fusion
+ * Loop-invariant code motion
+ * Loop unroll
+* Other
+ * Generate WebGPU initializers
+ * Graphics robust access
+ * Upgrade memory model to VulkanKHR
+
+Additionally, certain sets of transformations have been packaged into
+higher-level recipes. These include:
+
+* Optimization for size (`spirv-opt -Os`)
+* Optimization for performance (`spirv-opt -O`)
For the latest list with detailed documentation, please refer to
[`include/spirv-tools/optimizer.hpp`](include/spirv-tools/optimizer.hpp).
