[clang] [Clang][Modules] Emit C++20 BMIs to working directory with -fmodule-output (PR #174560)

[via cfe-commits]

================
@@ -51,7 +51,7 @@
 
 // RUN: %clang -std=c++20 Hello.cppm --precompile -fmodules-reduced-bmi \
 // RUN:     -### 2>&1 | FileCheck Hello.cppm \
-// RUN:     --check-prefix=CHECK-OVERRIDE-WARN
+// RUN:     --check-prefix=CHECK-OVERRIDE-WARN-NOT
----------------
CarvedCoder wrote:

it seems removing these lines would be better
`
// RUN: %clang -std=c++20 Hello.cppm --precompile -fmodules-reduced-bmi \
// RUN:     -### 2>&1 | FileCheck Hello.cppm \
// RUN:     --check-prefix=CHECK-OVERRIDE-WARN

// RUN: %clang -std=c++20 Hello.cppm --precompile -fmodules-reduced-bmi \
// RUN:     -o Hello.pcm -### 2>&1 | FileCheck Hello.cppm \
// RUN:    --check-prefix=CHECK-OVERRIDE-WARN

// CHECK-OVERRIDE-WARN: warning: the implicit output of reduced BMI may be overrided ...
// CHECK-OVERRIDE-WARN-NOT: warning:
`
because after fixing the reduced BMI output path to resolve relative to the working directory, the implicit and explicit outputs no longer conflict. As a result, the override warning is no longer emitted, and the existing checks are asserting obsolete behavior.

https://github.com/llvm/llvm-project/pull/174560