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comment/style fixes 

From-SVN: r135493
This commit is contained in:
Xinliang David Li 2008-05-18 04:37:59 +00:00 committed by Xinliang David Li
parent afa55b38c8
commit e29cc9b402
5 changed files with 92 additions and 51 deletions
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12
ChangeLog
View File

@ -1,13 +1,11 @@
2008-05-18 Xinliang David Li <davidxl@google.com>
* ChangeLog: Remove wrong ChangeLog entry.
2008-05-17 Xinliang David Li <davidxl@google.com>
* gcc/tree-ssa-dce.c : conditional dead call elimination
* gcc/opts.c : enable the optimization at >=O2
* gcc/common.opt : new flag for control the optimization
* gcc/doc/invoke.texi : documentation change
* gcc/testsuite/gcc.dg/cdce1.c : new test case
* gcc/testsuite/gcc.dg/cdce2.c : new test case
*MAINTAINERS : Add myself (write after approval)
* MAINTAINERS (Write After Approval): Add myself.
2008-05-15 Janus Weil <janus@gcc.gnu.org>

33
gcc/ChangeLog
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@ -1,3 +1,17 @@
2008-05-18 Xinliang David Li <davidxl@google.com>
* gcc/tree-ssa-dce.c: Coding style fix.
(check_pow): Documentation comment.
(check_log): Documenation comment. Coding style fix.
(is_unnecessary_except_errno_call): Ditto.
(gen_conditions_for_pow): Ditto.
(gen_conditions_for_log): Ditto.
(gen_shrink_wrap_conditions): Ditto.
(shrink_wrap_one_built_in_calls): Ditto.
* gcc/doc/invoke.texi: Better documentation string.
* ChangeLog: Fix wrong change log entries from
May 17 checkin on function call DCE.
2008-05-17 Kaz Kojima <kkojima@gcc.gnu.org>
* config/sh/sh.c (sh_output_mi_thunk): Update the use of
@ -12,6 +26,25 @@
* fold-const.c (fold_unary) <CASE_CONVERT>: Fold the cast into
a BIT_AND_EXPR only for an INTEGER_TYPE.
2008-05-17 Xinliang David Li <davidxl@google.com>
* gcc/tree-ssa-dce.c (cond_dead_built_in_calls): New static variable.
(check_pow, check_log, is_unnecessary_except_errno_call): New
functions to check for eliminating math functions that are pure
except for setting errno.
(gen_conditions_for_pow, gen_conditionas_for_log): New functions to
general condition expressions for shrink-wrapping pow/log calls.
(gen_shrink_wrap_conditions): Ditto.
(shrink_wrap_one_built_in_call): Ditto.
(shrink_wrap_conditional_dead_built_in_calls): Ditto.
(mark_operand_necessary): If debugging, output if OP is necessary.
(eliminate_unnecessary_stmts): Eliminate pow, log calls that are
unnecessary.
* gcc/opts.c (decode_options): set flag_tree_builtin_dce to 1 when
opt level >= 2.
* gcc/common.opt: New user flag -ftree-builtin-dce.
* gcc/doc/invoke.texi (-ftree-builtin-dce): New option.
2008-05-16 David S. Miller <davem@davemloft.net>
* config/sparc/linux.h (NO_PROFILE_COUNTERS): Undef before

6
gcc/doc/invoke.texi
View File

@ -5876,9 +5876,9 @@ default at @option{-O} and higher.
@item -ftree-builtin-dce
@opindex ftree-builtin-dce
Perform conditional dead code elimination (DCE) on builtin calls that
may set errno but are otherwise side-effect free. This flag is enabled by
default at @option{-O} and higher.
Perform conditional dead code elimination (DCE) for calls to builtin functions
that may set errno but are otherwise side-effect free. This flag is enabled by
default at @option{-O2} and higher.
@item -ftree-dominator-opts
@opindex ftree-dominator-opts

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2008-05-17 Xinliang David Li <davidxl@google.com>
* gcc.dg/cdce1.c: New test
* gcc.dg/cdce2.c: New test
2008-05-17 Tobias Burnus <burnus@net-b.de>
* gfortran.dg/initialization_19.f90: New test.

87
gcc/tree-ssa-dce.c
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@ -217,7 +217,7 @@ find_all_control_dependences (struct edge_list *el)
if (error_cond(args))
built_in_call(args)
( An actual simple exampl is :
An actual simple exampl is :
log (x); // Mostly dead call
==>
if (x < 0)
@ -226,7 +226,7 @@ find_all_control_dependences (struct edge_list *el)
in majority of the cases, log won't be called with x out of
range. The branch is totally predicatible, so the branch cost
is low. Such optimization improves the performance of
an important application in a big search company by 20% )
an important application in a big search company.
Note that library functions are not supposed to clear errno to zero without
error.
@ -245,6 +245,10 @@ find_all_control_dependences (struct edge_list *el)
inlining). */
/* A helper method to help select calls to pow that are suitable for
conditional DCE transformation. Returns true if the pow call is
a candidate.*/
static bool
check_pow (tree pow_call)
{
@ -325,6 +329,10 @@ check_pow (tree pow_call)
return false;
}
/* A helper function to help select candidate calls to log that are
suitable for conditional DCE. Returns true if the log call is a
candidate. */
static bool
check_log (tree log_call)
{
@ -340,8 +348,9 @@ check_log (tree log_call)
}
/* A helper function to determine if a builtin function
call is a candidate for conditional DCE. */
/* A helper function to determine if a builtin function call is a
candidate for conditional DCE. Returns true if the builtin call
is a candidate. */
static bool
is_unnecessary_except_errno_call (tree call)
@ -353,9 +362,7 @@ is_unnecessary_except_errno_call (tree call)
if (!flag_tree_builtin_dce)
return false;
gcc_assert (call);
gcc_assert (!DECL_P (call));
gcc_assert (TREE_CODE (call) == CALL_EXPR);
gcc_assert (call && TREE_CODE (call) == CALL_EXPR);
fn = get_callee_fndecl (call);
if (!fn || !DECL_BUILT_IN (fn))
@ -363,24 +370,21 @@ is_unnecessary_except_errno_call (tree call)
fnc = DECL_FUNCTION_CODE (fn);
switch (fnc)
{
CASE_FLT_FN (BUILT_IN_POW):
if (check_pow (call))
is_unnecessary_except_errno = true;
break;
{
CASE_FLT_FN (BUILT_IN_POW):
if (check_pow (call))
is_unnecessary_except_errno = true;
break;
CASE_FLT_FN (BUILT_IN_LOG):
if (check_log (call))
is_unnecessary_except_errno = true;
break;
default :
is_unnecessary_except_errno = false;
break;
CASE_FLT_FN (BUILT_IN_LOG):
if (check_log (call))
is_unnecessary_except_errno = true;
break;
default :
is_unnecessary_except_errno = false;
break;
}
if (!is_unnecessary_except_errno)
return false;
return is_unnecessary_except_errno;
}
@ -717,10 +721,11 @@ propagate_necessity (struct edge_list *el)
}
}
/* Method to generate conditional statements for guarding condionally
dead calls to pow. One or more statements can be generated for
each logical condition. Statement groups of different conditions
are separated by a NULL tree. */
/* Method to generate conditional statements for guarding condionally
dead calls to pow. One or more statements can be generated for
each logical condition. Statement groups of different conditions
are separated by a NULL tree and they are stored in the VEC
conds. The number of logical conditions are stored in *nconds. */
static void
gen_conditions_for_pow (tree pow_call, enum built_in_function fnc,
VEC (tree, heap)* conds, unsigned * nconds)
@ -872,7 +877,7 @@ gen_conditions_for_pow (tree pow_call, enum built_in_function fnc,
VEC_safe_push (tree, heap, conds, stmt3);
(*nconds)++;
/* now a seperator*/
/* Now a seperator*/
VEC_safe_push (tree, heap, conds, NULL);
temp1 = create_tmp_var (int_typ, "DCE_COND1");
@ -893,8 +898,8 @@ gen_conditions_for_pow (tree pow_call, enum built_in_function fnc,
gcc_unreachable ();
}
/* The method to generate error condition guard code for log(x)
calls. */
/* The method to generate error condition guard code for log(x)
calls. */
static void
gen_conditions_for_log (tree call, enum built_in_function fnc,
VEC (tree, heap)* conds, unsigned * nconds)
@ -956,8 +961,8 @@ gen_shrink_wrap_conditions (tree bi_call, VEC (tree, heap)* conds, unsigned int
enum built_in_function fnc;
gcc_assert (nconds && conds);
gcc_assert (VEC_length(tree, conds) == 0);
gcc_assert (TREE_CODE (bi_call) == GIMPLE_MODIFY_STMT ||
TREE_CODE (bi_call) == CALL_EXPR);
gcc_assert (TREE_CODE (bi_call) == GIMPLE_MODIFY_STMT
|| TREE_CODE (bi_call) == CALL_EXPR);
call = bi_call;
if (TREE_CODE (call) == GIMPLE_MODIFY_STMT)
@ -969,19 +974,17 @@ gen_shrink_wrap_conditions (tree bi_call, VEC (tree, heap)* conds, unsigned int
*nconds = 0;
switch (fnc)
{
/*CASE_FLT_FN(BUILT_IN_POW)*/
{
case BUILT_IN_POW:
gen_conditions_for_pow (call, fnc, conds, nconds);
break;
/*CASE_FLT_FN(BUILT_IN_LOG):*/
break;
case BUILT_IN_LOG:
case BUILT_IN_LOGF:
case BUILT_IN_LOGL:
gen_conditions_for_log (call, fnc, conds, nconds);
break;
break;
default :
gcc_assert (0);
gcc_unreachable();
break;
}
@ -990,6 +993,7 @@ gen_shrink_wrap_conditions (tree bi_call, VEC (tree, heap)* conds, unsigned int
}
/* Propability of the branch (to the call) is taken. */
#define ERR_PROB 0.01
/* The method to shrink wrap a partially dead builtin call
@ -1044,7 +1048,8 @@ shrink_wrap_one_built_in_call (tree bi_call)
{
tree c = VEC_index (tree, conds, ci);
gcc_assert ( c || ci != 0 );
if (!c) break;
if (!c)
break;
bsi_insert_before (&bi_call_bsi, c, BSI_SAME_STMT);
cond_expr = c;
}
@ -1052,7 +1057,7 @@ shrink_wrap_one_built_in_call (tree bi_call)
ci ++;
gcc_assert (cond_expr && TREE_CODE (cond_expr) == COND_EXPR);
/* now the label*/
/* Now the label*/
bi_call_label_decl = create_artificial_label ();
bi_call_label = build1 (LABEL_EXPR, void_type_node, bi_call_label_decl);
bsi_insert_before (&bi_call_bsi, bi_call_label, BSI_SAME_STMT);
@ -1068,7 +1073,7 @@ shrink_wrap_one_built_in_call (tree bi_call)
join_tgt_in_edge_fall_thru->probability =
REG_BR_PROB_BASE - bi_call_in_edge0->probability;
/* code generation for the rest of the conditions */
/* Code generation for the rest of the conditions */
guard_bb = guard_bb0;
for (; nconds > 0; )
{
@ -1095,7 +1100,7 @@ shrink_wrap_one_built_in_call (tree bi_call)
bi_call_in_edge = make_edge (guard_bb, bi_call_bb, EDGE_TRUE_VALUE);
bi_call_in_edge->probability = REG_BR_PROB_BASE*ERR_PROB;
bi_call_in_edge->probability = REG_BR_PROB_BASE * ERR_PROB;
guard_bb_in_edge->probability =
REG_BR_PROB_BASE - bi_call_in_edge->probability;