114 lines
4.4 KiB
Diff
114 lines
4.4 KiB
Diff
From 129d96b9ab5a2445d0fc2c3f7b72baa0453bd93f Mon Sep 17 00:00:00 2001
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From: Xi Ruoyao <xry111@xry111.site>
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Date: Wed, 14 Jun 2023 08:24:05 +0800
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Subject: [PATCH 047/124] LoongArch: Set default alignment for functions and
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labels with -mtune
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The LA464 micro-architecture is sensitive to alignment of code. The
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Loongson team has benchmarked various combinations of function, the
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results [1] show that 16-byte label alignment together with 32-byte
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function alignment gives best results in terms of SPEC score.
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Add a mtune-based table-driven mechanism to set the default of
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-falign-{functions,labels}. As LA464 is the first (and the only for
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now) uarch supported by GCC, the same setting is also used for
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the "generic" -mtune=loongarch64. In the future we may set different
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settings for LA{2,3,6}64 once we add the support for them.
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Bootstrapped and regtested on loongarch64-linux-gnu. Ok for trunk?
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gcc/ChangeLog:
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* config/loongarch/loongarch-tune.h (loongarch_align): New
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struct.
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* config/loongarch/loongarch-def.h (loongarch_cpu_align): New
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array.
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* config/loongarch/loongarch-def.c (loongarch_cpu_align): Define
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the array.
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* config/loongarch/loongarch.cc
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(loongarch_option_override_internal): Set the value of
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-falign-functions= if -falign-functions is enabled but no value
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is given. Likewise for -falign-labels=.
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Signed-off-by: Peng Fan <fanpeng@loongson.cn>
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Signed-off-by: ticat_fp <fanpeng@loongson.cn>
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---
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gcc/config/loongarch/loongarch-def.c | 12 ++++++++++++
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gcc/config/loongarch/loongarch-def.h | 1 +
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gcc/config/loongarch/loongarch-tune.h | 8 ++++++++
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gcc/config/loongarch/loongarch.cc | 6 ++++++
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4 files changed, 27 insertions(+)
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diff --git a/gcc/config/loongarch/loongarch-def.c b/gcc/config/loongarch/loongarch-def.c
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index 80ab10a52..74d422ce0 100644
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--- a/gcc/config/loongarch/loongarch-def.c
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+++ b/gcc/config/loongarch/loongarch-def.c
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@@ -72,6 +72,18 @@ loongarch_cpu_cache[N_TUNE_TYPES] = {
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},
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};
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+struct loongarch_align
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+loongarch_cpu_align[N_TUNE_TYPES] = {
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+ [CPU_LOONGARCH64] = {
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+ .function = "32",
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+ .label = "16",
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+ },
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+ [CPU_LA464] = {
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+ .function = "32",
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+ .label = "16",
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+ },
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+};
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+
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/* The following properties cannot be looked up directly using "cpucfg".
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So it is necessary to provide a default value for "unknown native"
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tune targets (i.e. -mtune=native while PRID does not correspond to
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diff --git a/gcc/config/loongarch/loongarch-def.h b/gcc/config/loongarch/loongarch-def.h
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index b5985f070..eb87a79a5 100644
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--- a/gcc/config/loongarch/loongarch-def.h
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+++ b/gcc/config/loongarch/loongarch-def.h
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@@ -144,6 +144,7 @@ extern int loongarch_cpu_issue_rate[];
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extern int loongarch_cpu_multipass_dfa_lookahead[];
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extern struct loongarch_cache loongarch_cpu_cache[];
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+extern struct loongarch_align loongarch_cpu_align[];
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extern struct loongarch_rtx_cost_data loongarch_cpu_rtx_cost_data[];
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#ifdef __cplusplus
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diff --git a/gcc/config/loongarch/loongarch-tune.h b/gcc/config/loongarch/loongarch-tune.h
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index 8e3eb2947..d961963f0 100644
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--- a/gcc/config/loongarch/loongarch-tune.h
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+++ b/gcc/config/loongarch/loongarch-tune.h
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@@ -48,4 +48,12 @@ struct loongarch_cache {
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int simultaneous_prefetches; /* number of parallel prefetch */
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};
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+/* Alignment for functions and labels for best performance. For new uarchs
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+ the value should be measured via benchmarking. See the documentation for
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+ -falign-functions and -falign-labels in invoke.texi for the format. */
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+struct loongarch_align {
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+ const char *function; /* default value for -falign-functions */
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+ const char *label; /* default value for -falign-labels */
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+};
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+
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#endif /* LOONGARCH_TUNE_H */
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diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
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index 4c0f393b6..f14de5cce 100644
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--- a/gcc/config/loongarch/loongarch.cc
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+++ b/gcc/config/loongarch/loongarch.cc
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@@ -6246,6 +6246,12 @@ loongarch_option_override_internal (struct gcc_options *opts)
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&& !opts->x_optimize_size)
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opts->x_flag_prefetch_loop_arrays = 1;
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+ if (opts->x_flag_align_functions && !opts->x_str_align_functions)
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+ opts->x_str_align_functions = loongarch_cpu_align[LARCH_ACTUAL_TUNE].function;
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+
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+ if (opts->x_flag_align_labels && !opts->x_str_align_labels)
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+ opts->x_str_align_labels = loongarch_cpu_align[LARCH_ACTUAL_TUNE].label;
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+
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if (TARGET_DIRECT_EXTERN_ACCESS && flag_shlib)
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error ("%qs cannot be used for compiling a shared library",
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"-mdirect-extern-access");
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--
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2.33.0
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