[llvm] [IR] Add new Range attribute using new ConstantRange Attribute type (PR #83171)

[Nikita Popov via llvm-commits]

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@@ -2997,6 +3000,51 @@ bool LLParser::parseRequiredTypeAttr(AttrBuilder &B, lltok::Kind AttrToken,
   return false;
 }
 
+/// parseRangeAttr
+///   ::= range(<ty> <n>,<n>)
+bool LLParser::parseRangeAttr(AttrBuilder &B) {
+  Lex.Lex();
+
+  APInt Lower;
+  APInt Upper;
+  Type *Ty = nullptr;
+  LocTy TyLoc;
+
+  auto ParseAPSInt = [&](llvm::TypeSize BitWidth, APInt &Val) {
+    if (Lex.getKind() != lltok::APSInt)
+      return tokError("expected integer");
+    if (Lex.getAPSIntVal().getBitWidth() > BitWidth)
+      return tokError("integer is to large for the BitWidth");
+    Val = Lex.getAPSIntVal().extend(BitWidth);
+    Lex.Lex();
+    return false;
+  };
+
+  if (!EatIfPresent(lltok::lparen))
+    return tokError("expected '('");
+  if (parseType(Ty, TyLoc))
+    return true;
+  if (!Ty->isIntegerTy())
+    return error(TyLoc, "The range must have integer type!");
+
+  auto BitWidth = Ty->getPrimitiveSizeInBits();
+
+  if (ParseAPSInt(BitWidth, Lower))
+    return true;
+  if (!EatIfPresent(lltok::comma))
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nikic wrote:

parseToken

https://github.com/llvm/llvm-project/pull/83171