[Bug rtl-optimization/49472] [4.7 regression] Compiler segfault on valid code

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49472

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|fortran                     |rtl-optimization
   Target Milestone|---                         |4.7.0
            Summary|[gfortran, 4.7 regression]  |[4.7 regression] Compiler
                   |Compiler segfault on valid  |segfault on valid code
                   |code                        |

--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-06-20 11:54:44 UTC ---
We endlessly recurse simplifying from fwprop

#20152 0x0000000001169de1 in propagate_rtx_1 (px=0x7fffffffd940, 
    old_rtx=0x7ffff5b3f7a0, new_rtx=0x7ffff5b48ba0, flags=6)
    at /space/rguenther/src/svn/trunk/gcc/fwprop.c:507
507           tem = simplify_gen_binary (code, mode, op0, op1);
(gdb) down
#20151 0x0000000000b0f51e in simplify_gen_binary (code=MULT, mode=DFmode, 
    op0=0x7ffff5b48bd0, op1=0x7ffff5b48ba0)
    at /space/rguenther/src/svn/trunk/gcc/simplify-rtx.c:117
117       tem = simplify_binary_operation (code, mode, op0, op1);
(gdb) call debug_rtx (op0)
(mult:DF (mult:DF (div:DF (reg:DF 80 [ D.1612 ])
            (reg:DF 123))
        (neg:DF (div:DF (const_double:DF 1.0e+0 [0x0.8p+1])
                (reg:DF 103 [ powroot.4 ]))))
    (reg:DF 82 [ D.1613 ]))
(gdb) call debug_rtx (op1)
(div:DF (reg:DF 80 [ D.1612 ])
    (reg:DF 123))