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| author | Bill Schmidt <wschmidt@linux.vnet.ibm.com> | 2012-09-11 12:23:25 +0000 |
|---|---|---|
| committer | William Schmidt <wschmidt@gcc.gnu.org> | 2012-09-11 12:23:25 +0000 |
| commit | ccdbfe9398e4c225706599e6b291f4cf0e616df8 (patch) | |
| tree | 3a554aee711b2212e5a769dd87e1616f33de6dbb /gcc | |
| parent | b8f4e58fbcd3fa19e8bdc65652e58b5c7f8d6f42 (diff) | |
| download | gcc-ccdbfe9398e4c225706599e6b291f4cf0e616df8.zip gcc-ccdbfe9398e4c225706599e6b291f4cf0e616df8.tar.gz gcc-ccdbfe9398e4c225706599e6b291f4cf0e616df8.tar.bz2 | |
re PR middle-end/55492 (__atomic_load doesn't match ACQUIRE memory model)
2012-09-11 Bill Schmidt <wschmidt@linux.vnet.ibm.com>
PR tree-optimization/55492
* doc/invoke.texi (max-slsr-cand-scan): New description.
* gimple-ssa-strength-reduction.c (find_basis_for_candidate): Limit
the time spent searching for a basis.
* params.def (PARAM_MAX_SLSR_CANDIDATE_SCAN): New param.
From-SVN: r191178
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 8 | ||||
| -rw-r--r-- | gcc/doc/invoke.texi | 5 | ||||
| -rw-r--r-- | gcc/gimple-ssa-strength-reduction.c | 7 | ||||
| -rw-r--r-- | gcc/params.def | 7 |
4 files changed, 26 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 77f65bd..c4b237c 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2012-09-11 Bill Schmidt <wschmidt@linux.vnet.ibm.com> + + PR tree-optimization/55492 + * doc/invoke.texi (max-slsr-cand-scan): New description. + * gimple-ssa-strength-reduction.c (find_basis_for_candidate): Limit + the time spent searching for a basis. + * params.def (PARAM_MAX_SLSR_CANDIDATE_SCAN): New param. + 2012-09-11 Richard Guenther <rguenther@suse.de> * gimple.h (gimple_register_type): Remove. diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 994e4db..1a854b0 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -9407,6 +9407,11 @@ having a regular register file and accurate register pressure classes. See @file{haifa-sched.c} in the GCC sources for more details. The default choice depends on the target. + +@item max-slsr-cand-scan +Set the maximum number of existing candidates that will be considered when +seeking a basis for a new straight-line strength reduction candidate. + @end table @end table diff --git a/gcc/gimple-ssa-strength-reduction.c b/gcc/gimple-ssa-strength-reduction.c index 0e770a9..87684b3 100644 --- a/gcc/gimple-ssa-strength-reduction.c +++ b/gcc/gimple-ssa-strength-reduction.c @@ -54,6 +54,7 @@ along with GCC; see the file COPYING3. If not see #include "domwalk.h" #include "pointer-set.h" #include "expmed.h" +#include "params.h" /* Information about a strength reduction candidate. Each statement in the candidate table represents an expression of one of the @@ -353,10 +354,14 @@ find_basis_for_candidate (slsr_cand_t c) cand_chain_t chain; slsr_cand_t basis = NULL; + // Limit potential of N^2 behavior for long candidate chains. + int iters = 0; + int max_iters = PARAM_VALUE (PARAM_MAX_SLSR_CANDIDATE_SCAN); + mapping_key.base_expr = c->base_expr; chain = (cand_chain_t) htab_find (base_cand_map, &mapping_key); - for (; chain; chain = chain->next) + for (; chain && iters < max_iters; chain = chain->next, ++iters) { slsr_cand_t one_basis = chain->cand; diff --git a/gcc/params.def b/gcc/params.def index c7f27fe..a4c930b 100644 --- a/gcc/params.def +++ b/gcc/params.def @@ -979,6 +979,13 @@ DEFPARAM (PARAM_SCHED_PRESSURE_ALGORITHM, "Which -fsched-pressure algorithm to apply", 1, 1, 2) +/* Maximum length of candidate scans in straight-line strength reduction. */ +DEFPARAM (PARAM_MAX_SLSR_CANDIDATE_SCAN, + "max-slsr-cand-scan", + "Maximum length of candidate scans for straight-line " + "strength reduction", + 50, 1, 999999) + /* Local variables: mode:c |