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

2 files changed, 16 insertions, 24 deletions

diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index dd0dea5b94a..40ab79509f9 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -1846,11 +1846,9 @@ llvm::Value* CodeGenFunction::EmitAsmInput(
       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;
diff --git a/clang/lib/Sema/SemaStmtAsm.cpp b/clang/lib/Sema/SemaStmtAsm.cpp
index b123a739a7a..9b051e02d12 100644
--- a/clang/lib/Sema/SemaStmtAsm.cpp
+++ b/clang/lib/Sema/SemaStmtAsm.cpp
@@ -383,25 +383,19 @@ StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
     } else if (Info.requiresImmediateConstant() && !Info.allowsRegister()) {
       if (!InputExpr->isValueDependent()) {
         Expr::EvalResult EVResult;
-        if (!InputExpr->EvaluateAsRValue(EVResult, Context, true))
-          return StmtError(
-              Diag(InputExpr->getBeginLoc(), diag::err_asm_immediate_expected)
-              << Info.getConstraintStr() << InputExpr->getSourceRange());
-
-        // For compatibility with GCC, we also allow pointers that would be
-        // integral constant expressions if they were cast to int.
-        llvm::APSInt IntResult;
-        if (!EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(),
-                                             Context))
-          return StmtError(
-              Diag(InputExpr->getBeginLoc(), diag::err_asm_immediate_expected)
-              << Info.getConstraintStr() << InputExpr->getSourceRange());
-
-        if (!Info.isValidAsmImmediate(IntResult))
-          return StmtError(Diag(InputExpr->getBeginLoc(),
-                                diag::err_invalid_asm_value_for_constraint)
-                           << IntResult.toString(10) << Info.getConstraintStr()
-                           << InputExpr->getSourceRange());
+        if (InputExpr->EvaluateAsRValue(EVResult, Context, true)) {
+          // For compatibility with GCC, we also allow pointers that would be
+          // integral constant expressions if they were cast to int.
+          llvm::APSInt IntResult;
+          if (EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(),
+                                               Context))
+            if (!Info.isValidAsmImmediate(IntResult))
+              return StmtError(Diag(InputExpr->getBeginLoc(),
+                                    diag::err_invalid_asm_value_for_constraint)
+                               << IntResult.toString(10)
+                               << Info.getConstraintStr()
+                               << InputExpr->getSourceRange());
+        }
       }
 
     } else {