[flang-commits] [flang] 9cfa899 - [flang] add a static assert in CheckUnitNumberInRangeImpl

[Jean Perier via flang-commits]

Author: Jean Perier
Date: 2022-04-11T09:32:52+02:00
New Revision: 9cfa899b87c583e0dcd20e4d35c8e9d337ee14f9

URL: https://github.com/llvm/llvm-project/commit/9cfa899b87c583e0dcd20e4d35c8e9d337ee14f9
DIFF: https://github.com/llvm/llvm-project/commit/9cfa899b87c583e0dcd20e4d35c8e9d337ee14f9.diff

LOG: [flang] add a static assert in CheckUnitNumberInRangeImpl

Add a check that CheckUnitNumberInRangeImpl is not needlessly instantiated.

Differential Revision: https://reviews.llvm.org/D123285

Added: 
    

Modified: 
    flang/runtime/io-api.cpp

Removed: 
    


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diff  --git a/flang/runtime/io-api.cpp b/flang/runtime/io-api.cpp
index 80f4583f42d63..43e49daa1284b 100644
--- a/flang/runtime/io-api.cpp
+++ b/flang/runtime/io-api.cpp
@@ -1280,6 +1280,9 @@ template <typename INT>
 static enum Iostat CheckUnitNumberInRangeImpl(INT unit, bool handleError,
     char *ioMsg, std::size_t ioMsgLength, const char *sourceFile,
     int sourceLine) {
+  static_assert(sizeof(INT) >= sizeof(ExternalUnit),
+      "only intended to be used when the INT to ExternalUnit conversion is "
+      "narrowing");
   if (unit != static_cast<ExternalUnit>(unit)) {
     Terminator oom{sourceFile, sourceLine};
     IoErrorHandler errorHandler{oom};