[AArch64][SVE]Add error message in the AsmParser for SVEPattern (#82668)

All assembly instructions that have an operand using sve_pred_enum and
mistakenly use '#' in front of it would fail without an error message.

Author: CarolineConcatto

llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp

@@ -7939,7 +7939,7 @@ ParseStatus AArch64AsmParser::tryParseSVEPattern(OperandVector &Operands) {
 
     auto *MCE = dyn_cast<MCConstantExpr>(ImmVal);
     if (!MCE)
-      return ParseStatus::Failure;
+      return TokError("invalid operand for instruction");
 
     Pattern = MCE->getValue();
   } else {

llvm/test/MC/AArch64/SVE/cntb-diagnostics.s

@@ -55,3 +55,8 @@ cntb  x0, vl512
 // CHECK: [[@LINE-1]]:{{[0-9]+}}: error: invalid operand
 // CHECK-NEXT: cntb  x0, vl512
 // CHECK-NOT: [[@LINE-1]]:{{[0-9]+}}:
+
+cntb  x0, #all, mul #1
+// CHECK: [[@LINE-1]]:{{[0-9]+}}: error: invalid operand for instruction
+// CHECK-NEXT: cntb  x0, #all, mul #1
+// CHECK-NOT: [[@LINE-1]]:{{[0-9]+}}:

llvm/test/MC/AArch64/SVE/ptrue-diagnostics.s

@@ -27,3 +27,8 @@ ptrue p0.s, #32
 // CHECK: [[@LINE-1]]:{{[0-9]+}}: error: invalid predicate pattern
 // CHECK-NEXT: ptrue p0.s, #32
 // CHECK-NOT: [[@LINE-3]]:{{[0-9]+}}:
+
+ptrue p0.s, #all
+// CHECK: [[@LINE-1]]:{{[0-9]+}}: error: invalid operand for instruction
+// CHECK-NEXT: ptrue p0.s, #all
+// CHECK-NOT: [[@LINE-3]]:{{[0-9]+}}:$