https://gcc.gnu.org/g:3390b0e262c7f26a440638a78e40866242067cf5
commit r15-11421-g3390b0e262c7f26a440638a78e40866242067cf5 Author: Thomas Koenig <[email protected]> Date: Sun Jul 26 13:41:32 2026 +0200 Fix size calculation for reallocation for matmul of rank 2 a and rank 1 b. This is a rather simple one-character (well, two-bit) fix for th calculation of the size of the reallocation of the LHS if that is allocatable. gcc/fortran/ChangeLog: PR fortran/126386 * frontend-passes.cc (matmul_lhs_realloc): Fix size calculation of A2B1 case. gcc/testsuite/ChangeLog: PR fortran/126386 * gfortran.dg/inline_matmul_28.f90: New test. (cherry picked from commit 4d855f3af5b18e539585d1d4832470e500323c12) Diff: --- gcc/fortran/frontend-passes.cc | 2 +- gcc/testsuite/gfortran.dg/inline_matmul_28.f90 | 21 +++++++++++++++++++++ 2 files changed, 22 insertions(+), 1 deletion(-) diff --git a/gcc/fortran/frontend-passes.cc b/gcc/fortran/frontend-passes.cc index 8e2b9d73c40d..cac2998a2f91 100644 --- a/gcc/fortran/frontend-passes.cc +++ b/gcc/fortran/frontend-passes.cc @@ -3565,7 +3565,7 @@ matmul_lhs_realloc (gfc_expr *c, gfc_expr *a, gfc_expr *b, ar->start[0] = get_array_inq_function (GFC_ISYM_SIZE, a, 1); cond = build_logical_expr (INTRINSIC_NE, get_array_inq_function (GFC_ISYM_SIZE, c, 1), - get_array_inq_function (GFC_ISYM_SIZE, a, 2)); + get_array_inq_function (GFC_ISYM_SIZE, a, 1)); break; case A1B2: diff --git a/gcc/testsuite/gfortran.dg/inline_matmul_28.f90 b/gcc/testsuite/gfortran.dg/inline_matmul_28.f90 new file mode 100644 index 000000000000..569c29c41c89 --- /dev/null +++ b/gcc/testsuite/gfortran.dg/inline_matmul_28.f90 @@ -0,0 +1,21 @@ +! { dg-do run } +! { dg-options "-ffrontend-optimize" } +! PR 126386 - size calculation for allocation of the lhs for matmmul +! was wrong. Original test case by Christoph Hofer. + +PROGRAM reallocation_bug + REAL(8), DIMENSION(:), ALLOCATABLE :: y + REAL(8), DIMENSION(3,2) :: A + real(8), dimension(3) :: x + + A(:,1) = [1,-2,3] + A(:,2) = [-4,5,6] + + x = [7,-8,9] + + ALLOCATE(y(3)) + y = matmul(transpose(2*a),x) + if (size(y,1) /= 2) stop 1 + if (any(y /= [100, -28])) stop 2 + +END PROGRAM reallocation_bug
