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reorg.c (mostly_true_jump): Use REG_BR_PROB notes when flag_branch_probabilities. 

* reorg.c (mostly_true_jump): Use REG_BR_PROB notes when
	flag_branch_probabilities.

From-SVN: r13819
This commit is contained in:
Doug Evans 1997-03-28 22:38:24 +00:00
parent 65f7a65344
commit a6c383b0d8
1 changed files with 20 additions and 0 deletions
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20
gcc/reorg.c
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@ -1350,6 +1350,26 @@ mostly_true_jump (jump_insn, condition)
int rare_dest = rare_destination (target_label);
int rare_fallthrough = rare_destination (NEXT_INSN (jump_insn));
/* If branch probabilities are available, then use that number since it
always gives a correct answer. */
if (flag_branch_probabilities)
{
rtx note = find_reg_note (jump_insn, REG_BR_PROB, 0);;
if (note)
{
int prob = XINT (note, 0);
if (prob >= REG_BR_PROB_BASE * 9 / 10)
return 2;
else if (prob >= REG_BR_PROB_BASE / 2)
return 1;
else if (prob >= REG_BR_PROB_BASE / 10)
return 0;
else
return -1;
}
}
/* If this is a branch outside a loop, it is highly unlikely. */
if (GET_CODE (PATTERN (jump_insn)) == SET
&& GET_CODE (SET_SRC (PATTERN (jump_insn))) == IF_THEN_ELSE