On Sun, Aug 30, 2020 at 11:24 AM Jakub Jelinek <ja...@redhat.com> wrote: > > On Fri, Aug 28, 2020 at 06:25:46PM +0200, Jakub Jelinek via Gcc-patches wrote: > > You're right, thanks for spotting it, I've missed native_encode_rtx will do > > quick_push rather than safe_push. > > > > Updated patch below, it shouldn't be needed in the second loop, because > > the first loop should already grow it to the largest size. > > Testing beyond a bug in i386.md revealed also that I've lost a cast to long > to avoid breaking 32-bit bootstrap. > > This is the version that passed bootstrap/regtest on both x86_64-linux and > i686-linux. In both bootstraps/regtests together, it saved (from the > statistics I've gathered) 63104 .rodata bytes (before constant merging), > in 6814 hits of the data->desc->mark = ~(*slot)->desc->labelno;. > > Ok for trunk?
OK. Thanks, Richard. > 2020-08-30 Jakub Jelinek <ja...@redhat.com> > > PR middle-end/54201 > * varasm.c: Include alloc-pool.h. > (output_constant_pool_contents): Emit desc->mark < 0 entries as > aliases. > (struct constant_descriptor_rtx_data): New type. > (constant_descriptor_rtx_data_cmp): New function. > (struct const_rtx_data_hasher): New type. > (const_rtx_data_hasher::hash, const_rtx_data_hasher::equal): New > methods. > (optimize_constant_pool): New function. > (output_shared_constant_pool): Call it if TARGET_SUPPORTS_ALIASES. > > --- gcc/varasm.c.jj 2020-07-28 15:39:10.091755086 +0200 > +++ gcc/varasm.c 2020-08-28 18:21:58.943759578 +0200 > @@ -57,6 +57,7 @@ along with GCC; see the file COPYING3. > #include "asan.h" > #include "rtl-iter.h" > #include "file-prefix-map.h" /* remap_debug_filename() */ > +#include "alloc-pool.h" > > #ifdef XCOFF_DEBUGGING_INFO > #include "xcoffout.h" /* Needed for external data declarations. */ > @@ -4198,7 +4199,27 @@ output_constant_pool_contents (struct rt > class constant_descriptor_rtx *desc; > > for (desc = pool->first; desc ; desc = desc->next) > - if (desc->mark) > + if (desc->mark < 0) > + { > +#ifdef ASM_OUTPUT_DEF > + const char *name = targetm.strip_name_encoding (XSTR (desc->sym, 0)); > + char label[256]; > + char buffer[256 + 32]; > + const char *p; > + > + ASM_GENERATE_INTERNAL_LABEL (label, "LC", ~desc->mark); > + p = targetm.strip_name_encoding (label); > + if (desc->offset) > + { > + sprintf (buffer, "%s+%ld", p, (long) (desc->offset)); > + p = buffer; > + } > + ASM_OUTPUT_DEF (asm_out_file, name, p); > +#else > + gcc_unreachable (); > +#endif > + } > + else if (desc->mark) > { > /* If the constant is part of an object_block, make sure that > the constant has been positioned within its block, but do not > @@ -4216,6 +4237,160 @@ output_constant_pool_contents (struct rt > } > } > > +struct constant_descriptor_rtx_data { > + constant_descriptor_rtx *desc; > + target_unit *bytes; > + unsigned short size; > + unsigned short offset; > + unsigned int hash; > +}; > + > +/* qsort callback to sort constant_descriptor_rtx_data * vector by > + decreasing size. */ > + > +static int > +constant_descriptor_rtx_data_cmp (const void *p1, const void *p2) > +{ > + constant_descriptor_rtx_data *const data1 > + = *(constant_descriptor_rtx_data * const *) p1; > + constant_descriptor_rtx_data *const data2 > + = *(constant_descriptor_rtx_data * const *) p2; > + if (data1->size > data2->size) > + return -1; > + if (data1->size < data2->size) > + return 1; > + if (data1->hash < data2->hash) > + return -1; > + gcc_assert (data1->hash > data2->hash); > + return 1; > +} > + > +struct const_rtx_data_hasher : nofree_ptr_hash<constant_descriptor_rtx_data> > +{ > + static hashval_t hash (constant_descriptor_rtx_data *); > + static bool equal (constant_descriptor_rtx_data *, > + constant_descriptor_rtx_data *); > +}; > + > +/* Hash and compare functions for const_rtx_data_htab. */ > + > +hashval_t > +const_rtx_data_hasher::hash (constant_descriptor_rtx_data *data) > +{ > + return data->hash; > +} > + > +bool > +const_rtx_data_hasher::equal (constant_descriptor_rtx_data *x, > + constant_descriptor_rtx_data *y) > +{ > + if (x->hash != y->hash || x->size != y->size) > + return 0; > + unsigned int align1 = x->desc->align; > + unsigned int align2 = y->desc->align; > + unsigned int offset1 = (x->offset * BITS_PER_UNIT) & (align1 - 1); > + unsigned int offset2 = (y->offset * BITS_PER_UNIT) & (align2 - 1); > + if (offset1) > + align1 = least_bit_hwi (offset1); > + if (offset2) > + align2 = least_bit_hwi (offset2); > + if (align2 > align1) > + return 0; > + if (memcmp (x->bytes, y->bytes, x->size * sizeof (target_unit)) != 0) > + return 0; > + return 1; > +} > + > +/* Attempt to optimize constant pool POOL. If it contains both CONST_VECTOR > + constants and scalar constants with the values of CONST_VECTOR elements, > + try to alias the scalar constants with the CONST_VECTOR elements. */ > + > +static void > +optimize_constant_pool (struct rtx_constant_pool *pool) > +{ > + auto_vec<target_unit, 128> buffer; > + auto_vec<constant_descriptor_rtx_data *, 128> vec; > + object_allocator<constant_descriptor_rtx_data> > + data_pool ("constant_descriptor_rtx_data_pool"); > + int idx = 0; > + size_t size = 0; > + for (constant_descriptor_rtx *desc = pool->first; desc; desc = desc->next) > + if (desc->mark > 0 > + && ! (SYMBOL_REF_HAS_BLOCK_INFO_P (desc->sym) > + && SYMBOL_REF_BLOCK (desc->sym))) > + { > + buffer.truncate (0); > + buffer.reserve (GET_MODE_SIZE (desc->mode)); > + if (native_encode_rtx (desc->mode, desc->constant, buffer, 0, > + GET_MODE_SIZE (desc->mode))) > + { > + constant_descriptor_rtx_data *data = data_pool.allocate (); > + data->desc = desc; > + data->bytes = NULL; > + data->size = GET_MODE_SIZE (desc->mode); > + data->offset = 0; > + data->hash = idx++; > + size += data->size; > + vec.safe_push (data); > + } > + } > + if (idx) > + { > + vec.qsort (constant_descriptor_rtx_data_cmp); > + unsigned min_size = vec.last ()->size; > + target_unit *bytes = XNEWVEC (target_unit, size); > + unsigned int i; > + constant_descriptor_rtx_data *data; > + hash_table<const_rtx_data_hasher> * htab > + = new hash_table<const_rtx_data_hasher> (31); > + size = 0; > + FOR_EACH_VEC_ELT (vec, i, data) > + { > + buffer.truncate (0); > + native_encode_rtx (data->desc->mode, data->desc->constant, > + buffer, 0, data->size); > + memcpy (bytes + size, buffer.address (), data->size); > + data->bytes = bytes + size; > + data->hash = iterative_hash (data->bytes, > + data->size * sizeof (target_unit), 0); > + size += data->size; > + constant_descriptor_rtx_data **slot > + = htab->find_slot_with_hash (data, data->hash, INSERT); > + if (*slot) > + { > + data->desc->mark = ~(*slot)->desc->labelno; > + data->desc->offset = (*slot)->offset; > + } > + else > + { > + unsigned int sz = 1 << floor_log2 (data->size); > + > + *slot = data; > + for (sz >>= 1; sz >= min_size; sz >>= 1) > + for (unsigned off = 0; off + sz <= data->size; off += sz) > + { > + constant_descriptor_rtx_data tmp; > + tmp.desc = data->desc; > + tmp.bytes = data->bytes + off; > + tmp.size = sz; > + tmp.offset = off; > + tmp.hash = iterative_hash (tmp.bytes, > + sz * sizeof (target_unit), 0); > + slot = htab->find_slot_with_hash (&tmp, tmp.hash, INSERT); > + if (*slot == NULL) > + { > + *slot = data_pool.allocate (); > + **slot = tmp; > + } > + } > + } > + } > + delete htab; > + XDELETE (bytes); > + } > + data_pool.release (); > +} > + > /* Mark all constants that are used in the current function, then write > out the function's private constant pool. */ > > @@ -4251,6 +4426,10 @@ output_constant_pool (const char *fnname > void > output_shared_constant_pool (void) > { > + if (optimize > + && TARGET_SUPPORTS_ALIASES) > + optimize_constant_pool (shared_constant_pool); > + > output_constant_pool_contents (shared_constant_pool); > } > > > > Jakub >