[clang] [flang] [flang] Align `-x` language modes with `gfortran` (PR #130268)

[Iñaki Amatria Barral via cfe-commits]

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@@ -0,0 +1,12 @@
+! This test verifies that using `-x f95` does not cause the driver to assume
+! this file is in fixed-form.
+
+program main
+  print *, "Hello, World!"
+end
+
+! RUN: %flang -### -x f95 %s 2>&1 | FileCheck --check-prefix=PRINT-PHASES %s
+! PRINT-PHASES-NOT: -ffixed-form
+
+! RUN: %flang -Werror -x f95 %s 2>&1 | FileCheck --check-prefix=COMPILE --allow-empty %s
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inaki-amatria wrote:

Fixed. I added `-fsyntax-only` to ensure this executes flang only

https://github.com/llvm/llvm-project/pull/130268