[llvm] [X86][AsmParser] Improve rel8 validation (PR #126073)

[Simon Pilgrim via llvm-commits]

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@@ -416,8 +416,16 @@ struct X86Operand final : public MCParsedAsmOperand {
       return isImm();
   }
 
-  bool isAbsMem16() const {
-    return isAbsMem() && Mem.ModeSize == 16;
+  bool isAbsMemMode16() const { return isAbsMem() && Mem.ModeSize == 16; }
+
+  bool isDispImm8() const {
+    if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(getMemDisp()))
+      return isImmSExti64i8Value(CE->getValue());
+    return true;
+  }
+
+  bool isAbsMem8() const {
+    return isAbsMem() && isMem8() && isDispImm8();
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RKSimon wrote:

clang-format this

https://github.com/llvm/llvm-project/pull/126073