[llvm] [LLVM][Tablegen] Add Default arguments support for Intrinsics in TableGen (PR #198557)

[Varad Rahul Kamthe via llvm-commits]

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@@ -397,38 +408,31 @@ CodeGenIntrinsic::CodeGenIntrinsic(const Record *R,
       SeenDefault = true;
     } else if (SeenDefault) {
       PrintFatalError(TheDef->getLoc(),
-                      "DefaultValue missing for argument " + Twine(i) +
-                          ". Defaults must form a contiguous trailing block "
-                          "ending at the last parameter.");
+                      "missing default argument on parameter " + Twine(i));
     }
   }
 
-  // Validate each declared default:
-  //  (a) the parameter is an integer type
-  //  (b) the default value fits in the declared integer width
+  // Validate each declared default: must be non-negative and fit in the
+  // parameter's integer width. Values are the raw bit pattern, so a negative
+  // is written in unsigned form (e.g. i8 -1 is 255).
   for (unsigned i = 0; i < ParamDefaultValues.size(); ++i) {
     if (!ParamDefaultValues[i].has_value())
       continue;
-    const Record *ParamTy = IS.ParamTys[i];
-    if (!ParamTy->isSubClassOf("LLVMType")) {
-      PrintFatalError(TheDef->getLoc(),
-                      "DefaultValue at argument " + Twine(i) +
-                          " requires an integer parameter type");
-    }
-    const Record *VT = ParamTy->getValueAsDef("VT");
+    const Record *VT = IS.ParamTys[i]->getValueAsDef("VT");
     if (!VT->getValueAsBit("isInteger")) {
       PrintFatalError(TheDef->getLoc(),
-                      "DefaultValue at argument " + Twine(i) +
+                      "default argument on parameter " + Twine(i) +
                           " requires an integer parameter type");
     }
     unsigned Width = VT->getValueAsInt("Size");
     int64_t Value = *ParamDefaultValues[i];
-    int64_t MaxUnsigned = (Width >= 64) ? INT64_MAX : ((1LL << Width) - 1);
-    int64_t MinSigned = (Width >= 64) ? INT64_MIN : -(1LL << (Width - 1));
-    if (Value < MinSigned || Value > MaxUnsigned) {
+    int64_t MaxValue =
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varadk27 wrote:

Switched the value storage and table to uint64_t and used isUIntN for the width check ; also lets the casts go away. Thanks!

https://github.com/llvm/llvm-project/pull/198557