http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56605
Steven Bosscher <steven at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |steven at gcc dot gnu.org
--- Comment #2 from Steven Bosscher <steven at gcc dot gnu.org> 2013-03-12
23:00:07 UTC ---
The first assumption is recorded at loop-iv.c:2472:
Breakpoint 7, iv_number_of_iterations (loop=0x3fffb5dc0ee0,
insn=0x3fffb5db6fa8, condition=0x3fffb5fd13c8, desc=0x3fffffffdf98)
at ../../trunk/gcc/loop-iv.c:2472
2472 alloc_EXPR_LIST (0, assumption,
desc->noloop_assumptions);
(gdb) p assumption
$1 = (rtx) 0x3fffb5fd1410
(gdb) p debug_rtx(assumption)
(eq:SI (subreg:SI (reg:DI 153 [ bnd.10D.2035+-4 ]) 4)
(const_int 0 [0]))
$2 = void
(gdb) cont
Continuing.
The second comes from loop-iv.c:2623:
Breakpoint 8, iv_number_of_iterations (loop=0x3fffb5dc0ee0,
insn=0x3fffb5db6fa8, condition=0x3fffb5fd13c8, desc=0x3fffffffdf98)
at ../../trunk/gcc/loop-iv.c:2623
2623 alloc_EXPR_LIST (0, assumption,
desc->noloop_assumptions);
(gdb) p debug_rtx(assumption)
(gtu:SI (plus:SI (subreg:SI (reg:DI 163 [ ivtmp.33D.2058+-4 ]) 4)
(const_int 1 [0x1]))
(subreg:SI (reg:DI 153 [ bnd.10D.2035+-4 ]) 4))
The second one is simplified using initial values at loop-iv.c:2777:
2777 simplify_using_initial_values (loop, IOR, &desc->noloop_assumptions);
(gdb) p debug_rtx(desc->noloop_assumptions)
(expr_list:REG_DEP_TRUE (gtu:SI (plus:SI (subreg:SI (reg:DI 163 [
ivtmp.33D.2058+-4 ]) 4)
(const_int 1 [0x1]))
(subreg:SI (reg:DI 153 [ bnd.10D.2035+-4 ]) 4))
(expr_list:REG_DEP_TRUE (eq:SI (subreg:SI (reg:DI 153 [ bnd.10D.2035+-4 ])
4)
(const_int 0 [0]))
(nil)))
$15 = void
(gdb) next
2778 simplify_using_initial_values (loop, IOR, &desc->infinite);
(gdb) p debug_rtx(desc->noloop_assumptions)
(expr_list:REG_DEP_TRUE (eq:SI (subreg:SI (reg:DI 153 [ bnd.10D.2035+-4 ]) 4)
(const_int 0 [0]))
(expr_list:REG_DEP_TRUE (eq:SI (subreg:SI (reg:DI 153 [ bnd.10D.2035+-4 ])
4)
(const_int 0 [0]))
(nil)))
$16 = void
(gdb)
Insofar I can claim to understand loop-iv.c, this is supposed to be
cleaned up by eliminate_implied_conditions.
