[flang] Reset lbounds for allocatable function results. #65286
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With HLFIR the lbounds for the ALLOCATABLE result are taken
from the mutable box created for the result, so the non-default
lbounds might be propagated further causing incorrect result, e.g.:
```
program p
real, allocatable :: p5(:)
allocate(p5, source=real_init())
print *, lbound(p5, 1) ! must print 1, but prints 7
contains
function real_init()
real, allocatable :: real_init(:)
allocate(real_init(7:8))
end function real_init
end program p
```
With FIR lowering the box passed for `source` has explicit lower
bound 1 at the call site, but the runtime box initialized by
`real_init` call still has lower bound 7. I am not sure if
the runtime box initialized b `real_init` will ever be accessed
in a debugger via Fortran variable names, but I think that
having the right runtime bounds that can be accessible via
examining registers/stack might be good in general. So I decided
to update the runtime bounds at the point of return.
This change "fixes" the test above for HLFIR.
Reviewed By: jeanPerier
Differential Revision: https://reviews.llvm.org/D156187
|
Is there a reason to re-open this review on github? I think existing reviews can just go through phab and github is just for new reviews. |
I just want to try the new workflow today, and I do not have any new patches yet. |
|
Ok no worries I just wasn't sure if you were actually looking for reviews since it's already accepted :) |
avillega
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to avillega/llvm-project
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Sep 11, 2023
With HLFIR the lbounds for the ALLOCATABLE result are taken from the
mutable box created for the result, so the non-default lbounds might be
propagated further causing incorrect result, e.g.:
```
program p
real, allocatable :: p5(:)
allocate(p5, source=real_init())
print *, lbound(p5, 1) ! must print 1, but prints 7
contains
function real_init()
real, allocatable :: real_init(:)
allocate(real_init(7:8))
end function real_init
end program p
```
With FIR lowering the box passed for `source` has explicit lower bound 1
at the call site, but the runtime box initialized by `real_init` call
still has lower bound 7. I am not sure if the runtime box initialized by
`real_init` will ever be accessed in a debugger via Fortran variable
names, but I think that having the right runtime bounds that can be
accessible via examining registers/stack might be good in general. So I
decided to update the runtime bounds at the point of return.
This change fixes the test above for HLFIR.
Reviewed By: jeanPerier
Differential Revision: https://reviews.llvm.org/D156187
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With HLFIR the lbounds for the ALLOCATABLE result are taken from the mutable box created for the result, so the non-default lbounds might be propagated further causing incorrect result, e.g.:
With FIR lowering the box passed for
sourcehas explicit lower bound 1 at the call site, but the runtime box initialized byreal_initcall still has lower bound 7. I am not sure if the runtime box initialized breal_initwill ever be accessed in a debugger via Fortran variable names, but I think that having the right runtime bounds that can be accessible via examining registers/stack might be good in general. So I decided to update the runtime bounds at the point of return.This change "fixes" the test above for HLFIR.
Reviewed By: jeanPerier
Differential Revision: https://reviews.llvm.org/D156187