[flang-commits] [clang] [flang] [flang] Add -finit-local= to initialize automatic variables (PR #216164)

[via flang-commits]

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@@ -1250,6 +1254,236 @@ getSafeRepackAttrs(Fortran::lower::AbstractConverter &converter) {
   return attrs.empty() ? mlir::ArrayAttr{} : builder.getArrayAttr(attrs);
 }
 
+//===----------------------------------------------------------------------===//
+// -finit-local= helpers
+//===----------------------------------------------------------------------===//
+
+/// Returns true when \p var is an automatic local variable eligible for
+/// -finit-local= initialization. Excluded: variables without a symbol,
+/// globals, dummy arguments, SAVE'd vars, ALLOCATABLE/POINTER, vars in
+/// an EQUIVALENCE set, and vars with explicit or default initialization.
+static bool shouldInitLocal(const Fortran::lower::pft::Variable &var) {
+  if (!var.hasSymbol() || var.isGlobal())
+    return false;
+  const Fortran::semantics::Symbol &sym = var.getSymbol();
+  if (Fortran::semantics::IsDummy(sym))
+    return false;
+  if (Fortran::semantics::IsSaved(sym))
+    return false;
+  if (Fortran::semantics::IsAllocatableOrPointer(sym))
+    return false;
+  if (Fortran::lower::hasDefaultInitialization(sym))
+    return false;
+  if (const auto *obj =
+          sym.detailsIf<Fortran::semantics::ObjectEntityDetails>())
+    if (obj->init())
+      return false;
+  if (Fortran::semantics::FindEquivalenceSet(sym))
+    return false;
+  return true;
----------------
MattPD wrote:

`shouldInitLocal` accepts CUDA device locals. Compiling `real, device :: x` with `-fcuda -finit-local=zero` lowers to `cuf.alloc` followed by a plain `fir.store`. The corresponding compilation without `-finit-local=zero` emits no store. A host assignment to CUDA device storage uses `cuf.data_transfer`.

Could `shouldInitLocal` exclude CUDA data attributes unless initialization uses a CUF transfer or memset? `needsRepack` already excludes them.

https://github.com/llvm/llvm-project/pull/216164