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author | Xi Ruoyao <xry111@xry111.site> | 2023-06-14 08:24:05 +0800 |
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committer | Xi Ruoyao <xry111@xry111.site> | 2023-06-15 15:40:43 +0800 |
commit | 19e4d4c34c98d19d64eb2a5ed3d252685b9470be (patch) | |
tree | 30530dfe63ec913593e2df85deac12d68219588e /gcc | |
parent | df071fbd467f0cb3711119ef41d74792fc5e6c8c (diff) | |
download | gcc-19e4d4c34c98d19d64eb2a5ed3d252685b9470be.zip gcc-19e4d4c34c98d19d64eb2a5ed3d252685b9470be.tar.gz gcc-19e4d4c34c98d19d64eb2a5ed3d252685b9470be.tar.bz2 |
LoongArch: Set default alignment for functions and labels with -mtune
The LA464 micro-architecture is sensitive to alignment of code. The
Loongson team has benchmarked various combinations of function, the
results [1] show that 16-byte label alignment together with 32-byte
function alignment gives best results in terms of SPEC score.
Add a mtune-based table-driven mechanism to set the default of
-falign-{functions,labels}. As LA464 is the first (and the only for
now) uarch supported by GCC, the same setting is also used for
the "generic" -mtune=loongarch64. In the future we may set different
settings for LA{2,3,6}64 once we add the support for them.
Bootstrapped and regtested on loongarch64-linux-gnu. Ok for trunk?
gcc/ChangeLog:
* config/loongarch/loongarch-tune.h (loongarch_align): New
struct.
* config/loongarch/loongarch-def.h (loongarch_cpu_align): New
array.
* config/loongarch/loongarch-def.c (loongarch_cpu_align): Define
the array.
* config/loongarch/loongarch.cc
(loongarch_option_override_internal): Set the value of
-falign-functions= if -falign-functions is enabled but no value
is given. Likewise for -falign-labels=.
Diffstat (limited to 'gcc')
-rw-r--r-- | gcc/config/loongarch/loongarch-def.c | 12 | ||||
-rw-r--r-- | gcc/config/loongarch/loongarch-def.h | 1 | ||||
-rw-r--r-- | gcc/config/loongarch/loongarch-tune.h | 8 | ||||
-rw-r--r-- | gcc/config/loongarch/loongarch.cc | 6 |
4 files changed, 27 insertions, 0 deletions
diff --git a/gcc/config/loongarch/loongarch-def.c b/gcc/config/loongarch/loongarch-def.c index fc4ebbe..6729c85 100644 --- a/gcc/config/loongarch/loongarch-def.c +++ b/gcc/config/loongarch/loongarch-def.c @@ -72,6 +72,18 @@ loongarch_cpu_cache[N_TUNE_TYPES] = { }, }; +struct loongarch_align +loongarch_cpu_align[N_TUNE_TYPES] = { + [CPU_LOONGARCH64] = { + .function = "32", + .label = "16", + }, + [CPU_LA464] = { + .function = "32", + .label = "16", + }, +}; + /* The following properties cannot be looked up directly using "cpucfg". So it is necessary to provide a default value for "unknown native" tune targets (i.e. -mtune=native while PRID does not correspond to diff --git a/gcc/config/loongarch/loongarch-def.h b/gcc/config/loongarch/loongarch-def.h index 778b140..fb8bb88 100644 --- a/gcc/config/loongarch/loongarch-def.h +++ b/gcc/config/loongarch/loongarch-def.h @@ -144,6 +144,7 @@ extern int loongarch_cpu_issue_rate[]; extern int loongarch_cpu_multipass_dfa_lookahead[]; extern struct loongarch_cache loongarch_cpu_cache[]; +extern struct loongarch_align loongarch_cpu_align[]; extern struct loongarch_rtx_cost_data loongarch_cpu_rtx_cost_data[]; #ifdef __cplusplus diff --git a/gcc/config/loongarch/loongarch-tune.h b/gcc/config/loongarch/loongarch-tune.h index ba31c4f..5c03262 100644 --- a/gcc/config/loongarch/loongarch-tune.h +++ b/gcc/config/loongarch/loongarch-tune.h @@ -48,4 +48,12 @@ struct loongarch_cache { int simultaneous_prefetches; /* number of parallel prefetch */ }; +/* Alignment for functions and labels for best performance. For new uarchs + the value should be measured via benchmarking. See the documentation for + -falign-functions and -falign-labels in invoke.texi for the format. */ +struct loongarch_align { + const char *function; /* default value for -falign-functions */ + const char *label; /* default value for -falign-labels */ +}; + #endif /* LOONGARCH_TUNE_H */ diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc index eb73d11..5b8b93e 100644 --- a/gcc/config/loongarch/loongarch.cc +++ b/gcc/config/loongarch/loongarch.cc @@ -6249,6 +6249,12 @@ loongarch_option_override_internal (struct gcc_options *opts) && !opts->x_optimize_size) opts->x_flag_prefetch_loop_arrays = 1; + if (opts->x_flag_align_functions && !opts->x_str_align_functions) + opts->x_str_align_functions = loongarch_cpu_align[LARCH_ACTUAL_TUNE].function; + + if (opts->x_flag_align_labels && !opts->x_str_align_labels) + opts->x_str_align_labels = loongarch_cpu_align[LARCH_ACTUAL_TUNE].label; + if (TARGET_DIRECT_EXTERN_ACCESS && flag_shlib) error ("%qs cannot be used for compiling a shared library", "-mdirect-extern-access"); |