Delay diagnosing asm constraints that require immediates until after inlining

Summary:
An inline asm call may result in an immediate input value after inlining.
Therefore, don't emit a diagnostic here if the input isn't an immediate.

Reviewers: joerg, eli.friedman, rsmith

Subscribers: asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, s.egerton, krytarowski, mgorny, riccibruno, eraman, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D60943

llvm-svn: 368104
diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index dd0dea5..40ab795 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -1846,11 +1846,9 @@
       InputExpr->EvaluateAsRValue(EVResult, getContext(), true);
 
       llvm::APSInt IntResult;
-      if (!EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(),
-                                           getContext()))
-        llvm_unreachable("Invalid immediate constant!");
-
-      return llvm::ConstantInt::get(getLLVMContext(), IntResult);
+      if (EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(),
+                                          getContext()))
+        return llvm::ConstantInt::get(getLLVMContext(), IntResult);
     }
 
     Expr::EvalResult Result;