[Mlir-commits] [mlir] [mlir][tosa] Add integer type conversion pass (PR #232853)

[Luke Hutton]

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@@ -217,6 +217,40 @@ def TosaGatherScatterHardeningPass
   }];
 }
 
+def TosaConvertIntegerTypesPass : Pass<"tosa-convert-integer-types", "ModuleOp"> {
+  let summary = "Convert selected TOSA integer types";
+  let description = [{
+    Converts integer types using `bitwidth-mappings`, a required list of
+    `<source>:<destination>` bitwidth pairs.
+    A typical use case is `bitwidth-mappings=4:8,48:64` which maps i4 and i48 to
+    i8 and i64 respectively.
+    Source bitwidths 1, 32 and 64 are not supported because some attributes
+    require these fixed widths.
+
+    Mappings apply once to the original width, preserving signedness and
+    leaving unmapped widths unchanged. Widening sign-extends signed and
+    signless constants and zero-extends unsigned constants. Narrowing truncates
+    without checking for data loss. The caller is responsible for ensuring the
+    conversion is appropriate.
+
+    Conversion covers types, function signatures and attribute payloads
+    throughout the module, including non-TOSA operations.
+    External callers and implementations must use the converted signatures.
+
+    Run after `tosa-validate`: converted IR may not conform to the TOSA
+    specification.
----------------
lhutton1 wrote:

It might be worth mentioning the intended use-case for this pass e.g. To enable conversion to other dialects / frameworks that don't support i4/i48 types

https://github.com/llvm/llvm-project/pull/232853