This happens in testcases gfortran.dg/vect/vect-[2,3,4].f90 -
On the alias branch we can't tell that subroutine arguments don't alias. e.g.,
X,Y in "SUBROUTINE SAXPY(X,Y,A)".
As a result the vectorizer applies loop-versioning with runtime aliasing test,
which also means it will handle misalignment using versioning instead of
peeling:
"
versioning for alias required: can't determine dependence between
(*x_32(D))[D.1518_28] and (*y_29(D))[D.1518_28]
vect-3.f90:6: note: mark for run-time aliasing test between
(*x_32(D))[D.1518_28] and (*y_29(D))[D.1518_28]
...
vect-3.f90:6: note: Alignment of access forced using versioning.
vect-3.f90:6: note: Versioning for alignment will be applied.
"
--
Summary: [alias-improvements-branch] can't alias fortran function
arguments
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: dorit at gcc dot gnu dot org
GCC build triplet: i386-linux
GCC host triplet: i386-linux
GCC target triplet: i386-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37692
