From 6fe8aea3c0b848cfca8a9dbeb6df42d51af2b18c Mon Sep 17 00:00:00 2001 From: Nils-Christian Kempke Date: Fri, 20 May 2022 17:15:44 +0200 Subject: testsuite, fortran: Remove self assignment non-statements There were a couple of places in the testsuite where instructions like var = var were written in the source code of tests. These were usually dummy statements meant to generate a line table entry at that line on which to break later on. This worked fine for gfortran and ifx, but it seems that, when compiled with ifort (2021.6.0) these statements do not actually create any assmbler instructions and especially no line table entries. Consider the program program test Integer var :: var = 1 var = var end program compiled with gfortran (13.0.0, -O0 -g). The linetable as emitted by 'objdump --dwarf=decodedline ./a.out' looks like test.f90: File name Line number Starting address View Stmt test.f90 1 0x401172 x test.f90 3 0x401176 x test.f90 4 0x401182 x test.f90 4 0x401185 x test.f90 4 0x401194 x test.f90 - 0x4011c0 actually containing line table info for line 3. Running gdb, breaking at 3 and checking the assembly we see 0x0000000000401172 <+0>: push %rbp 0x0000000000401173 <+1>: mov %rsp,%rbp => 0x0000000000401176 <+4>: mov 0x2ebc(%rip),%eax # 0x404038 0x000000000040117c <+10>: mov %eax,0x2eb6(%rip) # 0x404038 0x0000000000401182 <+16>: nop 0x0000000000401183 <+17>: pop %rbp 0x0000000000401184 <+18>: ret so two mov instructions are being issued for this assignment one copying the value into a register and one writing it back to the same memory. Ifort (2021.6.0, -O0 -g) on the other hand does not emit anything here and also has no line table entry: test.f90: File name Line number Starting address View Stmt test.f90 1 0x4040f8 x test.f90 4 0x404109 x test.f90 4 0x40410e x test.f90 - 0x404110 As I do not think that this is really a bug (on either side, gfortran/ifx or ifort), and as I don't think this behavior is covered in the Fortran standard, I changed these lines to become actual value assignments. This removes a few FAILs in the testsuite when ran with ifort. Approved-by: Tom Tromey --- gdb/testsuite/gdb.fortran/library-module-main.f90 | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'gdb/testsuite/gdb.fortran/library-module-main.f90') diff --git a/gdb/testsuite/gdb.fortran/library-module-main.f90 b/gdb/testsuite/gdb.fortran/library-module-main.f90 index 6b5fe87..85f9e6f 100644 --- a/gdb/testsuite/gdb.fortran/library-module-main.f90 +++ b/gdb/testsuite/gdb.fortran/library-module-main.f90 @@ -19,5 +19,5 @@ call lib_func if (var_i .ne. 2) call abort if (var_j .ne. 3) call abort - var_i = var_i ! i-is-2-in-main + var_i = 7 ! i-is-2-in-main end -- cgit v1.1