[flang-commits] [flang] 71d80cd - [flang] Fix msvc 17.3 build.

[Michael Kruse via flang-commits]

Author: Michael Kruse
Date: 2022-08-24T16:48:19-05:00
New Revision: 71d80cd6ed77a790685190d26479ecff7567dca7

URL: https://github.com/llvm/llvm-project/commit/71d80cd6ed77a790685190d26479ecff7567dca7
DIFF: https://github.com/llvm/llvm-project/commit/71d80cd6ed77a790685190d26479ecff7567dca7.diff

LOG: [flang] Fix msvc 17.3 build.

Compile fix for Microsoft Visual Studio 17.3 (msvc 14.33.31629) which regressed from 17.1.

The compile error is:
```
llvm-project\flang\lib\Evaluate\fold-integer.cpp(802,41): error C2672: 'invoke': no matching overloaded function found
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.33.31629\include\type_traits(1552,19): message : could be 'unknown-type std::invoke(_Callable &&,_Ty1 &&,_Types2 &&...) noexcept(<expr>)'
llvm-project\flang\lib\Evaluate\fold-integer.cpp(802,41): message : Failed to specialize function template 'unknown-type std::invoke(_Callable &&,_Ty1 &&,_Types2 &&...) noexcept(<expr>)'
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.33.31629\include\type_traits(1552): message : see declaration of 'std::invoke'
llvm-project\flang\lib\Evaluate\fold-integer.cpp(490,1): message : With the following template arguments:
llvm-project\flang\lib\Evaluate\fold-integer.cpp(490,1): message : '_Callable=int (__cdecl Fortran::evaluate::value::Integer<16,true,16,unsigned short,unsigned int>::* &)(void) const'
llvm-project\flang\lib\Evaluate\fold-integer.cpp(490,1): message : '_Ty1=const Fortran::evaluate::value::Integer<8,true,8,unsigned char,unsigned short> &'
llvm-project\flang\lib\Evaluate\fold-integer.cpp(490,1): message : '_Types2={}'
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.33.31629\include\type_traits(1546,19): message : or       'unknown-type std::invoke(_Callable &&) noexcept(<expr>)'
C:\Users\meinersbur\src\llvm-project\flang\lib\Evaluate\fold-integer.cpp(802,41): message : 'unknown-type std::invoke(_Callable &&) noexcept(<expr>)': expects 1 arguments - 2 provided
```

For some reason, msvc thinks that the lambda argument is `Scalar<T>` instead of `Scalar<TI>` as declared. This only happens in nested closures, using a lambda without `[]` arguments makes the problem disappear. Using `auto` instead to automatically derive the type fixes the problem.

I recently updated the version of Visual Studio on [[ https://lab.llvm.org/buildbot/#/builders/172 | flang-x86_64-windows buildbot  ]] which since then fails because of this problem. It occasionally failed with 'fatal error C1001: Internal compiler error." internal error which I hoped to fix with an update.

Reviewed By: klausler

Differential Revision: https://reviews.llvm.org/D132594

Added: 
    

Modified: 
    flang/lib/Evaluate/fold-integer.cpp

Removed: 
    


################################################################################
diff  --git a/flang/lib/Evaluate/fold-integer.cpp b/flang/lib/Evaluate/fold-integer.cpp
index b19b2db34bbaf..0a69e2c61b3d5 100644
--- a/flang/lib/Evaluate/fold-integer.cpp
+++ b/flang/lib/Evaluate/fold-integer.cpp
@@ -798,7 +798,10 @@ Expr<Type<TypeCategory::Integer, KIND>> FoldIntrinsicFunction(
                   "missing case to fold intrinsic function %s", name.c_str());
             }
             return FoldElementalIntrinsic<T, TI>(context, std::move(funcRef),
-                ScalarFunc<T, TI>([&fptr](const Scalar<TI> &i) -> Scalar<T> {
+                // `i` should be declared as `const Scalar<TI>&`.
+                // We declare it as `auto` to workaround an msvc bug:
+                // https://developercommunity.visualstudio.com/t/Regression:-nested-closure-assumes-wrong/10130223
+                ScalarFunc<T, TI>([&fptr](const auto &i) -> Scalar<T> {
                   return Scalar<T>{std::invoke(fptr, i)};
                 }));
           },