[flang] Parse failure after spurious "Possible truncated Hollerith literal"

[hawkinsp]

flang-new (built from LLVM commit 748922b) fails to parse
https://github.com/python-control/Slycot/blob/v0.3.5/slycot/src/MC03MD.f

$ flang-new -c slycot/src/MC03MD.f
./slycot/src/MC03MD.f:318:19: warning: Possible truncated Hollerith literal
                 DO 100 H = 1, CP2
                    ^^^^^^^^^^^^^^
error: Semantic errors in slycot/src/MC03MD.f
./slycot/src/MC03MD.f:318:30: error: No explicit type declared for 'CP2'
                 DO 100 H = 1, CP2
                               ^^^

gfortran 12.2.0 is happy with this file.

[llvmbot]

@llvm/issue-subscribers-flang-frontend

[adegomme]

same messages and error encountered when trying compiling https://github.com/Reference-ScaLAPACK/scalapack with flang-new, for example at https://github.com/Reference-ScaLAPACK/scalapack/blob/master/TOOLS/pilaprnt.f#L165

[klausler]

https://reviews.llvm.org/D150406