Contains the following improvements:
Fixes 1341: Atomics (and other instructions with side-effects) removed.
Add folding for redundant add/sub/mul/div/mix operations
Add constant folding rules for floating-point comparison
Add folding of redundant OpSelect insns
Add folding of OpCompositeExtract and OpConstantComposite
Update SPIRV-Tools. Relevant functional changes:
- Optimizer enhancements:
- ADCE now removes OpSwitch
- Block merging occurs in more cases
- Optimizer fixes:
- Constant propagation (CCP): support matrix constants
- #1199: Optimizer: Fix CCP: don't propagate spec constants.
- #1203: Optimizer: Fix common uniform elim bug introduced by refactoring.
- #1210: Optimizer: Aggressive dead code elimination: Fix 'break' identification.
- #1212: Optimizer: Aggressive dead code elimination: Was skipping too many instructions.
- #1214: Optimizer: Aggressive dead code elimination: Fix infinite loop.
- #1228: Optimizer: Fix CCP: Handling of varying Phi nodes; was resulting in infinite loop.
- #1245: Optimizer: Dead branch elimination: Avoid a null pointer dereference.
- #1250: Optimizer: Dead branch elimination: Avoid spuriously reporting a change.
- #1262: Support building on VisualStudio 2013 again
Update SPIRV-Headers, with "unified1" directory.
Updated one Glslang legalization test base result due to better block merging.
Also added known-good mechanism to fetch latest validated spirv-tools.
Also added -Od and -Os to disable optimizer and optimize for size.
Fetching spirv-tools is optional for both glsl and hlsl. Legalization
of hlsl is done by default if spirv-opt is present at cmake time.
Optimization for glsl is currently done through the option -Os.
Legalization testing is currently only done on four existing shaders.
A separate baseLegalResults directory holds those results. All previous
testing is done with the optimizer disabled.
