The instruction selection pass for SPIR-V now performs dead code
elimination (DCE).
This change removes unused instructions, leading to more optimized
SPIR-V output.
As a consequence of this, several tests were updated to ensure their
continued
correctness and to prevent previously tested code from being optimized
away.
Specifically:
- Many tests now store computed values into global variables to ensure
they are
not eliminated by DCE, allowing their code generation to be verified.
- The test `keep-tracked-const.ll` was removed because it no longer
tested
its original intent. The check statements in this test were for
constants
generated when expanding a G_TRUNC instruction, which is now removed by
DCE
instead of being expanded.
- A new test, `remove-dead-type-intrinsics.ll`, was added to confirm
that dead
struct types are correctly removed by the compiler.
These updates improve the SPIR-V backends optimization capabilities and
maintain the robustness of the test suite.
---------
Co-authored-by: Nathan Gauër <github@keenuts.net>
