Verifier: Enforce value of llvm.is.fpclass test mask

[arsenm]

Summary

As requested in D137811

[jyknight]

llvm/lib/IR/Verifier.cpp

5016

I might avoid saying "has 10 bits" in the error string since that seems likely to forget to be updated. Maybe something like "Unsupported bits passed to llvm.is.fpclass test mask."? (Just choose something and commit.)

[arsenm]

e20a092838f31c365b0e8a8d74b0b33d01e8117b

llvm/lib/IR/Verifier.cpp

Check(GV && GV->isConstant() && GV->hasDefinitiveInitializer(),
           "info argument of llvm.coro.id must refer to an initialized "
           "constant");
     Constant *Init = GV->getInitializer();
     Check(isa<ConstantStruct>(Init) || isa<ConstantArray>(Init),
           "info argument of llvm.coro.id must refer to either a struct or "
           "an array");
     break;
   }
+  case Intrinsic::is_fpclass: {
+    const ConstantInt *TestMask = cast<ConstantInt>(Call.getOperand(1));
+    Check((TestMask->getZExtValue() & ~fcAllFlags) == 0,
+          "llvm.is.fpclass test mask only has 10 bits");
+    break;
+  }
   case Intrinsic::fptrunc_round: {
     // Check the rounding mode
     Metadata *MD = nullptr;
     auto *MAV = dyn_cast<MetadataAsValue>(Call.getOperand(1));
     if (MAV)
       MD = MAV->getMetadata();
 
     Check(MD != nullptr, "missing rounding mode argument", Call);

llvm/test/Verifier/llvm.is.fpclass.ll

+; RUN: not llvm-as < %s 2>&1 | FileCheck %s
+
+; CHECK: immarg operand has non-immediate parameter
+; CHECK-NEXT: i32 %variable
+; CHECK-NEXT: %ret = call i1 @llvm.is.fpclass.f64(double %val, i32 %variable)
+define i1 @test_mask_variable(double %val, i32 %variable) {
+  %ret = call i1 @llvm.is.fpclass.f64(double %val, i32 %variable)
+  ret i1 %ret
+}
+
+; CHECK: llvm.is.fpclass test mask only has 10 bits
+define i1 @test_mask_neg1(double %val) {
+  %ret = call i1 @llvm.is.fpclass.f64(double %val, i32 -1)
+  ret i1 %ret
+}
+
+; CHECK: llvm.is.fpclass test mask only has 10 bits
+define i1 @test_mask_bit11(double %val) {
+  %ret = call i1 @llvm.is.fpclass.f64(double %val, i32 2048)
+  ret i1 %ret
+}
+
+declare i1 @llvm.is.fpclass.f64(double, i32 immarg)