[clang] [CIR] Split side_effect into memory effects, nounwind, and willreturn (PR #223890)

[Erich Keane via cfe-commits]

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@@ -1986,39 +1986,74 @@ def CIR_BlockAddrDiffAttr
 }
 
 //===----------------------------------------------------------------------===//
-// Side Effect
+// Memory Effects
 //===----------------------------------------------------------------------===//
 
-def CIR_SideEffect : CIR_I32Enum<
-    "SideEffect", "allowed side effects of a function", [
-      I32EnumCase<"All", 0, "all">,
-      I32EnumCase<"Pure", 1, "pure">,
-      I32EnumCase<"Const", 2, "const">
+def CIR_ModRefInfo : CIR_I32Enum<
+    "ModRefInfo", "how a function accesses one class of memory", [
+      I32EnumCase<"NoModRef", 0, "none">,
+      I32EnumCase<"Ref", 1, "read">,
+      I32EnumCase<"Mod", 2, "write">,
+      I32EnumCase<"ModRef", 3, "readwrite">
 ]> {
   let description = [{
-    The side effect attribute specifies the possible side effects of a function
-    or the target of a call operation.  This is an enumeration attribute with
-    the following possible values:
-
-    - all: The function or callee can have any side effects. This is the default
-      if no side effects are explicitly listed.
-    - pure: The function or callee may read data from memory, but it cannot
-      write data to memory. This has the same effect as the GNU C/C++ attribute
-      `__attribute__((pure))`.
-    - const: The function or callee may not read or write data from memory. This
-      has the same effect as the GNU C/C++ attribute `__attribute__((const))`.
+    Whether a function may read and/or write one class of memory.  The
+    spellings match LLVM's, so `none` means neither read nor written and
+    `readwrite` means both may happen.
+  }];
+}
 
-    Examples:
+def CIR_MemoryEffectsAttr : CIR_Attr<"MemoryEffects", "memory_effects"> {
+  let summary = "What memory a function or callee may touch";
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erichkeane wrote:

This needs a reworking too.

https://github.com/llvm/llvm-project/pull/223890