condexec merge part 6
Richard Henderson
rth@cygnus.com
Wed Apr 26 23:02:00 GMT 2000
Always estimate branch probabilities if we don't have real data.
This code does a better job than mostly_true_jump from reorg.c
(which should now be gutted, but I didn't yet); can be used to
set branch prediction bits on branches; and will shortly be used
to control whether or not certain if-conversion changes are
performed, and from which side of the branch.
Also fixes a bug in jump.c.
r~
* jump.c (invert_jump): Always invert REG_BR_PROB. Do it correctly.
* bb-reorder.c (reorder_basic_blocks): Don't run estimate_probability.
* flow.c (calculate_loop_depth): Remove.
* output.h (calculate_loop_depth): Don't declare.
* toplev.c (rest_of_compilation): Expand calculate_loop_depth
inline; run estimate_probability at the same time.
Index: bb-reorder.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/bb-reorder.c,v
retrieving revision 1.5
diff -c -p -d -r1.5 bb-reorder.c
*** bb-reorder.c 2000/04/18 01:32:43 1.5
--- bb-reorder.c 2000/04/27 05:54:40
*************** reorder_basic_blocks ()
*** 813,822 ****
/* Dump loop information. */
flow_loops_dump (&loops_info, rtl_dump_file, 0);
- /* Estimate using heuristics if no profiling info is available. */
- if (! flag_branch_probabilities)
- estimate_probability (&loops_info);
-
reorder_last_visited = BASIC_BLOCK (0);
for (i = 0; i < n_basic_blocks; i++)
--- 813,818 ----
Index: flow.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/flow.c,v
retrieving revision 1.261
diff -c -p -d -r1.261 flow.c
*** flow.c 2000/04/27 05:42:25 1.261
--- flow.c 2000/04/27 05:54:40
*************** tidy_fallthru_edges ()
*** 2469,2491 ****
tidy_fallthru_edge (s, b, c);
}
}
-
- /* Discover and record the loop depth at the head of each basic block. */
-
- void
- calculate_loop_depth (dump)
- FILE *dump;
- {
- struct loops loops;
-
- /* The loop infrastructure does the real job for us. */
- flow_loops_find (&loops);
-
- if (dump)
- flow_loops_dump (&loops, dump, 0);
-
- flow_loops_free (&loops);
- }
/* Perform data flow analysis.
F is the first insn of the function; FLAGS is a set of PROP_* flags
--- 2469,2474 ----
Index: jump.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/jump.c,v
retrieving revision 1.117
diff -c -p -d -r1.117 jump.c
*** jump.c 2000/04/18 22:34:10 1.117
--- jump.c 2000/04/27 05:54:40
*************** invert_jump (jump, nlabel)
*** 4431,4447 ****
if (redirect_jump (jump, nlabel))
{
! if (flag_branch_probabilities)
! {
! rtx note = find_reg_note (jump, REG_BR_PROB, 0);
! /* An inverted jump means that a probability taken becomes a
! probability not taken. Subtract the branch probability from the
! probability base to convert it back to a taken probability.
! (We don't flip the probability on a branch that's never taken. */
! if (note && XINT (XEXP (note, 0), 0) >= 0)
! XINT (XEXP (note, 0), 0) = REG_BR_PROB_BASE - XINT (XEXP (note, 0), 0);
! }
return 1;
}
--- 4431,4443 ----
if (redirect_jump (jump, nlabel))
{
! /* An inverted jump means that a probability taken becomes a
! probability not taken. Subtract the branch probability from the
! probability base to convert it back to a taken probability. */
! rtx note = find_reg_note (jump, REG_BR_PROB, 0);
! if (note)
! XEXP (note, 0) = GEN_INT (REG_BR_PROB_BASE - INTVAL (XEXP (note, 0)));
return 1;
}
Index: output.h
===================================================================
RCS file: /cvs/gcc/egcs/gcc/output.h,v
retrieving revision 1.46
diff -c -p -d -r1.46 output.h
*** output.h 2000/04/27 04:42:08 1.46
--- output.h 2000/04/27 05:54:40
*************** extern int regno_clobbered_at_setjmp PAR
*** 134,140 ****
extern void dump_flow_info PARAMS ((FILE *));
extern void find_basic_blocks PARAMS ((rtx, int, FILE *));
extern void cleanup_cfg PARAMS ((rtx));
- extern void calculate_loop_depth PARAMS ((FILE *));
extern void free_basic_block_vars PARAMS ((int));
extern void set_block_num PARAMS ((rtx, int));
#endif
--- 134,139 ----
Index: toplev.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/toplev.c,v
retrieving revision 1.324
diff -c -p -d -r1.324 toplev.c
*** toplev.c 2000/04/27 04:42:09 1.324
--- toplev.c 2000/04/27 05:54:40
*************** rest_of_compilation (decl)
*** 3246,3252 ****
find_basic_blocks (insns, max_reg_num (), rtl_dump_file);
cleanup_cfg (insns);
if (optimize)
! calculate_loop_depth (rtl_dump_file);
life_analysis (insns, rtl_dump_file, PROP_FINAL);
mark_constant_function ();
});
--- 3246,3267 ----
find_basic_blocks (insns, max_reg_num (), rtl_dump_file);
cleanup_cfg (insns);
if (optimize)
! {
! struct loops loops;
!
! /* Discover and record the loop depth at the head of each basic
! block. The loop infrastructure does the real job for us. */
! flow_loops_find (&loops);
!
! /* Estimate using heuristics if no profiling info is available. */
! if (! flag_branch_probabilities)
! estimate_probability (&loops);
!
! if (rtl_dump_file)
! flow_loops_dump (&loops, rtl_dump_file, 0);
!
! flow_loops_free (&loops);
! }
life_analysis (insns, rtl_dump_file, PROP_FINAL);
mark_constant_function ();
});
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