[Mlir-commits] [mlir] [mlir][emitc] Add EmitC index types (PR #93155)

[Corentin Ferry]

================
@@ -37,3 +37,28 @@ void mlir::populateEmitCSizeTTypeConversions(TypeConverter &converter) {
   converter.addTargetMaterialization(materializeAsUnrealizedCast);
   converter.addArgumentMaterialization(materializeAsUnrealizedCast);
 }
+
+/// Get an unsigned data type as wide as \p ty.
----------------
cferry-AMD wrote:

We don't need to mention the width, but the value must be preserved across casts, as they're mainly issued to adapt the signedness of a single MLIR `index`-type value in the C world. We can say the values will be preserved as long as they fit the types' ranges... but in this case we don't guarantee back and forth value-preserving casts for _any_ value that can be represented with these types. I should probably lower my expectation and be fine with this.

https://github.com/llvm/llvm-project/pull/93155