/* params.def - Run-time parameters.
- Copyright (C) 2001 Free Software Foundation, Inc.
+ Copyright (C) 2001, 2002, 2004, 2005 Free Software Foundation, Inc.
Written by Mark Mitchell <mark@codesourcery.com>.
This file is part of GCC.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA.
+Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301, USA.
*/
/* This file contains definitions for language-independent
- parameters. The DEFPARAM macro takes 4 arguments:
+ parameters. The DEFPARAM macro takes 6 arguments:
- The enumeral corresponding to this parameter.
- A default value for the parameter.
+ - The minimum acceptable value for the parameter.
+
+ - The maximum acceptable value for the parameter (if greater than
+ the minimum).
+
Be sure to add an entry to invoke.texi summarizing the parameter. */
-/* The maximum number of instructions accepted for inlining a
- function. Increasing values mean more agressive inlining.
- This affects currently only functions explicitly marked as
- inline (or methods defined within the class definition for C++).
- The original default value of 10000 was arbitrary and caused
- significant compile-time performance regressions. */
-DEFPARAM (PARAM_MAX_INLINE_INSNS,
- "max-inline-insns",
- "The maximum number of instructions in a function that is eligible for inlining",
- 600)
+/* The maximum number of fields in a variable with only implicit uses
+ for which structure aliasing will consider trying to track each
+ field. The default is 5. */
+DEFPARAM (PARAM_SALIAS_MAX_IMPLICIT_FIELDS,
+ "salias-max-implicit-fields",
+ "The maximum number of fields in a structure variable without direct structure accesses that GCC will attempt to track separately",
+ 5, 0, 0)
+
+/* The maximum structure size at which the scalar replacement of
+ aggregates (SRA) pass will perform block copies. The default
+ value, 0, implies that GCC will select the most appropriate size
+ itself. */
+DEFPARAM (PARAM_SRA_MAX_STRUCTURE_SIZE,
+ "sra-max-structure-size",
+ "The maximum structure size (in bytes) for which GCC will "
+ "use by-element copies",
+ 0, 0, 0)
+
+/* The maximum number of structure fields which the SRA pass will
+ instantiate to avoid block copies. The default value, 0, implies
+ that GCC will select the appropriate value itself. */
+DEFPARAM (PARAM_SRA_MAX_STRUCTURE_COUNT,
+ "sra-max-structure-count",
+ "The maximum number of structure fields for which GCC will "
+ "use by-element copies",
+ 0, 0, 0)
+
+/* The ratio between instantiated fields and the complete structure
+ size. We say that if the ratio of the number of bytes in
+ instantiated fields to the number of bytes in the complete
+ structure exceeds this parameter, or if the number of instantiated
+ fields to the total number of fields exceeds this parameter, then
+ block copies are not used. The default is 75%. */
+DEFPARAM (PARAM_SRA_FIELD_STRUCTURE_RATIO,
+ "sra-field-structure-ratio",
+ "The threshold ratio between instantiated fields and the total structure size",
+ 75, 0, 100)
+
+/* The single function inlining limit. This is the maximum size
+ of a function counted in internal gcc instructions (not in
+ real machine instructions) that is eligible for inlining
+ by the tree inliner.
+ The default value is 450.
+ Only functions marked inline (or methods defined in the class
+ definition for C++) are affected by this.
+ There are more restrictions to inlining: If inlined functions
+ call other functions, the already inlined instructions are
+ counted and once the recursive inline limit (see
+ "max-inline-insns" parameter) is exceeded, the acceptable size
+ gets decreased. */
+DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
+ "max-inline-insns-single",
+ "The maximum number of instructions in a single function eligible for inlining",
+ 450, 0, 0)
+
+/* The single function inlining limit for functions that are
+ inlined by virtue of -finline-functions (-O3).
+ This limit should be chosen to be below or equal to the limit
+ that is applied to functions marked inlined (or defined in the
+ class declaration in C++) given by the "max-inline-insns-single"
+ parameter.
+ The default value is 90. */
+DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
+ "max-inline-insns-auto",
+ "The maximum number of instructions when automatically inlining",
+ 90, 0, 0)
+DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
+ "max-inline-insns-recursive",
+ "The maximum number of instructions inline function can grow to via recursive inlining",
+ 450, 0, 0)
+
+DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
+ "max-inline-insns-recursive-auto",
+ "The maximum number of instructions non-inline function can grow to via recursive inlining",
+ 450, 0, 0)
+
+DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
+ "max-inline-recursive-depth",
+ "The maximum depth of recursive inlining for inline functions",
+ 8, 0, 0)
+
+DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
+ "max-inline-recursive-depth-auto",
+ "The maximum depth of recursive inlining for non-inline functions",
+ 8, 0, 0)
+
+DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY,
+ "min-inline-recursive-probability",
+ "Inline recursively only when the probability of call being executed exceeds the parameter",
+ 10, 0, 0)
+
+/* Limit the number of expansions created by the variable expansion
+ optimization to avoid register pressure. */
+DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
+ "max-variable-expansions-in-unroller",
+ "If -fvariable-expansion-in-unroller is used, the maximum number of \
+ times that an individual variable will be expanded \
+ during loop unrolling",
+ 1, 0, 0)
+
/* The maximum number of instructions to consider when looking for an
instruction to fill a delay slot. If more than this arbitrary
number of instructions is searched, the time savings from filling
DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
"max-delay-slot-insn-search",
"The maximum number of instructions to consider to fill a delay slot",
- 100)
+ 100, 0, 0)
/* When trying to fill delay slots, the maximum number of instructions
to consider when searching for a block with valid live register
DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
"max-delay-slot-live-search",
"The maximum number of instructions to consider to find accurate live register information",
- 333)
+ 333, 0, 0)
/* This parameter limits the number of branch elements that the
scheduler will track anti-dependencies through without resetting
DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
"max-pending-list-length",
"The maximum length of scheduling's pending operations list",
- 32)
+ 32, 0, 0)
+
+DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
+ "large-function-insns",
+ "The size of function body to be considered large",
+ 2700, 0, 0)
+DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
+ "large-function-growth",
+ "Maximal growth due to inlining of large function (in percent)",
+ 100, 0, 0)
+DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
+ "inline-unit-growth",
+ "how much can given compilation unit grow because of the inlining (in percent)",
+ 50, 0, 0)
+DEFPARAM(PARAM_INLINE_CALL_COST,
+ "inline-call-cost",
+ "expense of call operation relative to ordinary arithmetic operations",
+ 16, 0, 0)
/* The GCSE optimization will be disabled if it would require
significantly more memory than this value. */
DEFPARAM(PARAM_MAX_GCSE_MEMORY,
"max-gcse-memory",
"The maximum amount of memory to be allocated by GCSE",
- 50 * 1024 * 1024)
-/* The number of repetitions of copy/const prop and PRE to run. */
+ 50 * 1024 * 1024, 0, 0)
+/* The number of repetitions of copy/const prop and PRE to run. */
DEFPARAM(PARAM_MAX_GCSE_PASSES,
"max-gcse-passes",
"The maximum number of passes to make when doing GCSE",
- 1)
-
+ 1, 1, 0)
+/* This is the threshold ratio when to perform partial redundancy
+ elimination after reload. We perform partial redundancy elimination
+ when the following holds:
+ (Redundant load execution count)
+ ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
+ (Added loads execution count) */
+DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
+ "gcse-after-reload-partial-fraction",
+ "The threshold ratio for performing partial redundancy elimination after reload",
+ 3, 0, 0)
+/* This is the threshold ratio of the critical edges execution count compared to
+ the redundant loads execution count that permits performing the load
+ redundancy elimination in gcse after reload. */
+DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
+ "gcse-after-reload-critical-fraction",
+ "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload",
+ 10, 0, 0)
/* This parameter limits the number of insns in a loop that will be unrolled,
- and by how much the loop is unrolled. */
+ and by how much the loop is unrolled.
+
+ This limit should be at most half of the peeling limits: loop unroller
+ decides to not unroll loops that iterate fewer than 2*number of allowed
+ unrollings and thus we would have loops that are neither peeled or unrolled
+ otherwise. */
DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
"max-unrolled-insns",
"The maximum number of instructions to consider to unroll in a loop",
- 100)
+ 200, 0, 0)
+/* This parameter limits how many times the loop is unrolled depending
+ on number of insns really executed in each iteration. */
+DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
+ "max-average-unrolled-insns",
+ "The maximum number of instructions to consider to unroll in a loop on average",
+ 80, 0, 0)
+/* The maximum number of unrollings of a single loop. */
+DEFPARAM(PARAM_MAX_UNROLL_TIMES,
+ "max-unroll-times",
+ "The maximum number of unrollings of a single loop",
+ 8, 0, 0)
+/* The maximum number of insns of a peeled loop. */
+DEFPARAM(PARAM_MAX_PEELED_INSNS,
+ "max-peeled-insns",
+ "The maximum number of insns of a peeled loop",
+ 400, 0, 0)
+/* The maximum number of peelings of a single loop. */
+DEFPARAM(PARAM_MAX_PEEL_TIMES,
+ "max-peel-times",
+ "The maximum number of peelings of a single loop",
+ 16, 0, 0)
+/* The maximum number of insns of a peeled loop. */
+DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
+ "max-completely-peeled-insns",
+ "The maximum number of insns of a completely peeled loop",
+ 400, 0, 0)
+/* The maximum number of peelings of a single loop that is peeled completely. */
+DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
+ "max-completely-peel-times",
+ "The maximum number of peelings of a single loop that is peeled completely",
+ 16, 0, 0)
+/* The maximum number of insns of a peeled loop that rolls only once. */
+DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
+ "max-once-peeled-insns",
+ "The maximum number of insns of a peeled loop that rolls only once",
+ 400, 0, 0)
+
+/* The maximum number of insns of an unswitched loop. */
+DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
+ "max-unswitch-insns",
+ "The maximum number of insns of an unswitched loop",
+ 50, 0, 0)
+/* The maximum level of recursion in unswitch_single_loop. */
+DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
+ "max-unswitch-level",
+ "The maximum number of unswitchings in a single loop",
+ 3, 0, 0)
+
+/* The maximum number of iterations of a loop the brute force algorithm
+ for analysis of # of iterations of the loop tries to evaluate. */
+DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
+ "max-iterations-to-track",
+ "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
+ 1000, 0, 0)
+
+DEFPARAM(PARAM_MAX_SMS_LOOP_NUMBER,
+ "max-sms-loop-number",
+ "Maximum number of loops to perform swing modulo scheduling on (mainly for debugging)",
+ -1, -1, -1)
+
+/* This parameter is used to tune SMS MAX II calculations. */
+DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
+ "sms-max-ii-factor",
+ "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
+ 100, 0, 0)
+DEFPARAM(PARAM_SMS_DFA_HISTORY,
+ "sms-dfa-history",
+ "The number of cycles the swing modulo scheduler considers when \
+ checking conflicts using DFA",
+ 0, 0, 0)
+DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
+ "sms-loop-average-count-threshold",
+ "A threshold on the average loop count considered by the swing modulo scheduler",
+ 0, 0, 0)
+
+DEFPARAM(HOT_BB_COUNT_FRACTION,
+ "hot-bb-count-fraction",
+ "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
+ 10000, 0, 0)
+DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
+ "hot-bb-frequency-fraction",
+ "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
+ 1000, 0, 0)
+DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
+ "tracer-dynamic-coverage-feedback",
+ "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
+ 95, 0, 100)
+DEFPARAM(TRACER_DYNAMIC_COVERAGE,
+ "tracer-dynamic-coverage",
+ "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
+ 75, 0, 100)
+DEFPARAM(TRACER_MAX_CODE_GROWTH,
+ "tracer-max-code-growth",
+ "Maximal code growth caused by tail duplication (in percent)",
+ 100, 0, 0)
+DEFPARAM(TRACER_MIN_BRANCH_RATIO,
+ "tracer-min-branch-ratio",
+ "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
+ 10, 0, 100)
+DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
+ "tracer-min-branch-probability-feedback",
+ "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
+ 80, 0, 100)
+DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
+ "tracer-min-branch-probability",
+ "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
+ 50, 0, 100)
+
+/* The maximum number of incoming edges to consider for crossjumping. */
+DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
+ "max-crossjump-edges",
+ "The maximum number of incoming edges to consider for crossjumping",
+ 100, 0, 0)
+
+/* The minimum number of matching instructions to consider for crossjumping. */
+DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
+ "min-crossjump-insns",
+ "The minimum number of matching instructions to consider for crossjumping",
+ 5, 0, 0)
+
+/* The maximum number of insns to duplicate when unfactoring computed gotos. */
+DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
+ "max-goto-duplication-insns",
+ "The maximum number of insns to duplicate when unfactoring computed gotos",
+ 8, 0, 0)
+
+/* The maximum length of path considered in cse. */
+DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
+ "max-cse-path-length",
+ "The maximum length of path considered in cse",
+ 10, 0, 0)
+
+/* The cost of expression in loop invariant motion that is considered
+ expensive. */
+DEFPARAM(PARAM_LIM_EXPENSIVE,
+ "lim-expensive",
+ "The minimum cost of an expensive expression in the loop invariant motion",
+ 20, 0, 0)
+
+/* Bound on number of candidates for induction variables below that
+ all candidates are considered for each use in induction variable
+ optimizations. */
+
+DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
+ "iv-consider-all-candidates-bound",
+ "Bound on number of candidates below that all candidates are considered in iv optimizations",
+ 30, 0, 0)
+
+/* The induction variable optimizations give up on loops that contain more
+ induction variable uses. */
+
+DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
+ "iv-max-considered-uses",
+ "Bound on number of iv uses in loop optimized in iv optimizations",
+ 250, 0, 0)
+
+/* If there are at most this number of ivs in the set, try removing unnecessary
+ ivs from the set always. */
+
+DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
+ "iv-always-prune-cand-set-bound",
+ "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
+ 10, 0, 0)
+
+DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
+ "scev-max-expr-size",
+ "Bound on size of expressions used in the scalar evolutions analyzer",
+ 20, 0, 0)
+
+/* The product of the next two is used to decide whether or not to
+ use .GLOBAL_VAR. See tree-dfa.c. */
+DEFPARAM(PARAM_GLOBAL_VAR_THRESHOLD,
+ "global-var-threshold",
+ "Given N calls and V call-clobbered vars in a function. Use .GLOBAL_VAR if NxV is larger than this limit",
+ 500000, 0, 0)
+
+DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
+ "max-cselib-memory-locations",
+ "The maximum memory locations recorded by cselib",
+ 500, 0, 0)
+
+#ifdef ENABLE_GC_ALWAYS_COLLECT
+# define GGC_MIN_EXPAND_DEFAULT 0
+# define GGC_MIN_HEAPSIZE_DEFAULT 0
+#else
+# define GGC_MIN_EXPAND_DEFAULT 30
+# define GGC_MIN_HEAPSIZE_DEFAULT 4096
+#endif
+
+DEFPARAM(GGC_MIN_EXPAND,
+ "ggc-min-expand",
+ "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
+ GGC_MIN_EXPAND_DEFAULT, 0, 0)
+
+DEFPARAM(GGC_MIN_HEAPSIZE,
+ "ggc-min-heapsize",
+ "Minimum heap size before we start collecting garbage, in kilobytes",
+ GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
+
+#undef GGC_MIN_EXPAND_DEFAULT
+#undef GGC_MIN_HEAPSIZE_DEFAULT
+
+DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
+ "max-reload-search-insns",
+ "The maximum number of instructions to search backward when looking for equivalent reload",
+ 100, 0, 0)
+
+DEFPARAM(PARAM_MAX_ALIASED_VOPS,
+ "max-aliased-vops",
+ "The maximum number of virtual operands allowed to represent aliases before triggering alias grouping",
+ 500, 0, 0)
+
+DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
+ "max-sched-region-blocks",
+ "The maximum number of blocks in a region to be considered for interblock scheduling",
+ 10, 0, 0)
+
+DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
+ "max-sched-region-insns",
+ "The maximum number of insns in a region to be considered for interblock scheduling",
+ 100, 0, 0)
+
+DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
+ "max-last-value-rtl",
+ "The maximum number of RTL nodes that can be recorded as combiner's last value",
+ 10000, 0, 0)
+
+/* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
+ {signed,unsigned} integral types. This determines N.
+ Experimentation shows 256 to be a good value. */
+DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
+ "integer-share-limit",
+ "The upper bound for sharing integer constants",
+ 256, 2, 2)
+
+/* Incremental SSA updates for virtual operands may be very slow if
+ there is a large number of mappings to process. In those cases, it
+ is faster to rewrite the virtual symbols from scratch as if they
+ had been recently introduced. This heuristic cannot be applied to
+ SSA mappings for real SSA names, only symbols kept in FUD chains.
+
+ PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual
+ mappings that should be registered to trigger the heuristic.
+
+ PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between
+ mappings and symbols. If the number of virtual mappings is
+ PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of
+ virtual symbols to be updated, then the updater switches to a full
+ update for those symbols. */
+DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS,
+ "min-virtual-mappings",
+ "Minimum number of virtual mappings to consider switching to full virtual renames",
+ 100, 0, 0)
+
+DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO,
+ "virtual-mappings-ratio",
+ "Ratio between virtual mappings and virtual symbols to do full virtual renames",
+ 3, 0, 0)
+
+DEFPARAM (PARAM_SSP_BUFFER_SIZE,
+ "ssp-buffer-size",
+ "The lower bound for a buffer to be considered for stack smashing protection",
+ 8, 1, 0)
+
/*
Local variables:
mode:c
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