------- Comment #31 from rguenth at gcc dot gnu dot org 2008-01-08 12:55
-------
Another hot assert is
static inline tree
memory_partition (tree sym)
{
tree tag;
/* MPTs belong to their own partition. */
if (TREE_CODE (sym) == MEMORY_PARTITION_TAG)
return sym;
gcc_assert (!is_gimple_reg (sym));
and is_gimple_reg isn't cheap either. For this testcase two thirds of
the calls are attributed to add_vars_for_offset (through add_v{use,def}):
0.50 0.01 135234172/199610365 add_vars_for_offset [27]
[114] 1.1 0.74 0.01 199610365 is_gimple_reg [114]
and it really isn't cheap:
CPU: AMD64 processors, speed 2000 MHz (estimated)
Counted CPU_CLK_UNHALTED events (Cycles outside of halt state) with a unit mask
of 0x00 (No unit mask) count 100000
samples % symbol name
545326 36.8318 ggc_alloc_stat
310838 20.9943 add_vars_for_offset
85655 5.7852 add_virtual_operand
69156 4.6709 finalize_ssa_stmt_operands
57057 3.8537 bitmap_set_bit
36755 2.4825 htab_find_with_hash
35915 2.4257 get_expr_operands
28207 1.9051 is_gimple_reg
23340 1.5764 referenced_var_lookup
wrapping the assert inside ENABLE_CHECKING buys us 2s or 2.5%. But this
is too much micro-optimizing for me ;)
I'd rather have the quadratic SSA rewriting in the unroller fixed.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34683
