From: Thomas Preud'homme Date: Wed, 14 Dec 2016 10:07:01 +0000 (+0000) Subject: Fix PR77673: bswap loads passed end of object X-Git-Tag: releases/gcc-5.5.0~641 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=90823811f91c1164e9d65eb93876b63149823858;p=thirdparty%2Fgcc.git Fix PR77673: bswap loads passed end of object 2016-12-14 Thomas Preud'homme Backport from mainline 2016-11-25 Thomas Preud'homme gcc/ PR tree-optimization/77673 * tree-ssa-math-opts.c (struct symbolic_number): Add new src field. (init_symbolic_number): Initialize src field from src parameter. (perform_symbolic_merge): Select most dominated statement as the source statement. Set src field of resulting n structure from the input src with the lowest address. (find_bswap_or_nop): Rename source_stmt into ins_stmt. (bswap_replace): Rename src_stmt into ins_stmt. Initially get source of load from src field rather than insertion statement. Cancel optimization if statement analyzed is not dominated by the insertion statement. (pass_optimize_bswap::execute): Rename src_stmt to ins_stmt. Compute dominance information. gcc/testsuite/ PR tree-optimization/77673 * gcc.dg/pr77673.c: New test. From-SVN: r243637 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 43277e0e6504..14d366747c19 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,22 @@ +2016-12-14 Thomas Preud'homme + + Backport from mainline + 2016-11-25 Thomas Preud'homme + + PR tree-optimization/77673 + * tree-ssa-math-opts.c (struct symbolic_number): Add new src field. + (init_symbolic_number): Initialize src field from src parameter. + (perform_symbolic_merge): Select most dominated statement as the + source statement. Set src field of resulting n structure from the + input src with the lowest address. + (find_bswap_or_nop): Rename source_stmt into ins_stmt. + (bswap_replace): Rename src_stmt into ins_stmt. Initially get source + of load from src field rather than insertion statement. Cancel + optimization if statement analyzed is not dominated by the insertion + statement. + (pass_optimize_bswap::execute): Rename src_stmt to ins_stmt. Compute + dominance information. + 2016-12-13 Thomas Preud'homme Backport from mainline diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index a60809152958..fd5f9ecfc979 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,11 @@ +2016-12-14 Thomas Preud'homme + + Backport from mainline + 2016-11-25 Thomas Preud'homme + + PR tree-optimization/77673 + * gcc.dg/pr77673.c: New test. + 2016-12-13 Thomas Preud'homme Backport from mainline diff --git a/gcc/testsuite/gcc.dg/pr77673.c b/gcc/testsuite/gcc.dg/pr77673.c new file mode 100644 index 000000000000..e03bcb9284d1 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr77673.c @@ -0,0 +1,19 @@ +/* { dg-do compile { target fpic } } */ +/* { dg-require-effective-target bswap32 } */ +/* { dg-options "-O2 -fPIC -fdump-tree-bswap" } */ +/* { dg-additional-options "-march=z900" { target s390*-*-* } } */ + +void mach_parse_compressed(unsigned char* ptr, unsigned long int* val) +{ + if (ptr[0] < 0xC0U) { + *val = ptr[0] + ptr[1]; + return; + } + + *val = ((unsigned long int)(ptr[0]) << 24) + | ((unsigned long int)(ptr[1]) << 16) + | ((unsigned long int)(ptr[2]) << 8) + | ptr[3]; +} + +/* { dg-final { scan-tree-dump-not "load_dst_\\d+ =.* if \\(" "bswap" } } */ diff --git a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c index 61b65bb824b1..3882652dcfc0 100644 --- a/gcc/tree-ssa-math-opts.c +++ b/gcc/tree-ssa-math-opts.c @@ -1645,6 +1645,7 @@ struct symbolic_number { tree base_addr; tree offset; HOST_WIDE_INT bytepos; + tree src; tree alias_set; tree vuse; unsigned HOST_WIDE_INT range; @@ -1746,6 +1747,7 @@ init_symbolic_number (struct symbolic_number *n, tree src) int size; n->base_addr = n->offset = n->alias_set = n->vuse = NULL_TREE; + n->src = src; /* Set up the symbolic number N by setting each byte to a value between 1 and the byte size of rhs1. The highest order byte is set to n->size and the @@ -1859,6 +1861,7 @@ perform_symbolic_merge (gimple source_stmt1, struct symbolic_number *n1, uint64_t inc; HOST_WIDE_INT start_sub, end_sub, end1, end2, end; struct symbolic_number *toinc_n_ptr, *n_end; + basic_block bb1, bb2; if (!n1->base_addr || !n2->base_addr || !operand_equal_p (n1->base_addr, n2->base_addr, 0)) @@ -1872,15 +1875,20 @@ perform_symbolic_merge (gimple source_stmt1, struct symbolic_number *n1, { n_start = n1; start_sub = n2->bytepos - n1->bytepos; - source_stmt = source_stmt1; } else { n_start = n2; start_sub = n1->bytepos - n2->bytepos; - source_stmt = source_stmt2; } + bb1 = gimple_bb (source_stmt1); + bb2 = gimple_bb (source_stmt2); + if (dominated_by_p (CDI_DOMINATORS, bb1, bb2)) + source_stmt = source_stmt1; + else + source_stmt = source_stmt2; + /* Find the highest address at which a load is performed and compute related info. */ end1 = n1->bytepos + (n1->range - 1); @@ -1937,6 +1945,7 @@ perform_symbolic_merge (gimple source_stmt1, struct symbolic_number *n1, n->vuse = n_start->vuse; n->base_addr = n_start->base_addr; n->offset = n_start->offset; + n->src = n_start->src; n->bytepos = n_start->bytepos; n->type = n_start->type; size = TYPE_PRECISION (n->type) / BITS_PER_UNIT; @@ -2147,7 +2156,7 @@ find_bswap_or_nop (gimple stmt, struct symbolic_number *n, bool *bswap) uint64_t cmpxchg = CMPXCHG; uint64_t cmpnop = CMPNOP; - gimple source_stmt; + gimple ins_stmt; int limit; /* The last parameter determines the depth search limit. It usually @@ -2157,9 +2166,9 @@ find_bswap_or_nop (gimple stmt, struct symbolic_number *n, bool *bswap) in libgcc, and for initial shift/and operation of the src operand. */ limit = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (gimple_expr_type (stmt))); limit += 1 + (int) ceil_log2 ((unsigned HOST_WIDE_INT) limit); - source_stmt = find_bswap_or_nop_1 (stmt, n, limit); + ins_stmt = find_bswap_or_nop_1 (stmt, n, limit); - if (!source_stmt) + if (!ins_stmt) return NULL; /* Find real size of result (highest non-zero byte). */ @@ -2201,7 +2210,7 @@ find_bswap_or_nop (gimple stmt, struct symbolic_number *n, bool *bswap) return NULL; n->range *= BITS_PER_UNIT; - return source_stmt; + return ins_stmt; } namespace { @@ -2250,7 +2259,7 @@ public: changing of basic block. */ static bool -bswap_replace (gimple cur_stmt, gimple src_stmt, tree fndecl, tree bswap_type, +bswap_replace (gimple cur_stmt, gimple ins_stmt, tree fndecl, tree bswap_type, tree load_type, struct symbolic_number *n, bool bswap) { gimple_stmt_iterator gsi; @@ -2258,18 +2267,24 @@ bswap_replace (gimple cur_stmt, gimple src_stmt, tree fndecl, tree bswap_type, gimple bswap_stmt; gsi = gsi_for_stmt (cur_stmt); - src = gimple_assign_rhs1 (src_stmt); + src = n->src; tgt = gimple_assign_lhs (cur_stmt); /* Need to load the value from memory first. */ if (n->base_addr) { - gimple_stmt_iterator gsi_ins = gsi_for_stmt (src_stmt); + gimple_stmt_iterator gsi_ins = gsi_for_stmt (ins_stmt); tree addr_expr, addr_tmp, val_expr, val_tmp; tree load_offset_ptr, aligned_load_type; gimple addr_stmt, load_stmt; unsigned align; HOST_WIDE_INT load_offset = 0; + basic_block ins_bb, cur_bb; + + ins_bb = gimple_bb (ins_stmt); + cur_bb = gimple_bb (cur_stmt); + if (!dominated_by_p (CDI_DOMINATORS, cur_bb, ins_bb)) + return false; align = get_object_alignment (src); /* If the new access is smaller than the original one, we need @@ -2301,7 +2316,7 @@ bswap_replace (gimple cur_stmt, gimple src_stmt, tree fndecl, tree bswap_type, /* Move cur_stmt just before one of the load of the original to ensure it has the same VUSE. See PR61517 for what could go wrong. */ - if (gimple_bb (cur_stmt) != gimple_bb (src_stmt)) + if (gimple_bb (cur_stmt) != gimple_bb (ins_stmt)) reset_flow_sensitive_info (gimple_assign_lhs (cur_stmt)); gsi_move_before (&gsi, &gsi_ins); gsi = gsi_for_stmt (cur_stmt); @@ -2474,6 +2489,7 @@ pass_optimize_bswap::execute (function *fun) memset (&nop_stats, 0, sizeof (nop_stats)); memset (&bswap_stats, 0, sizeof (bswap_stats)); + calculate_dominance_info (CDI_DOMINATORS); FOR_EACH_BB_FN (bb, fun) { @@ -2485,7 +2501,7 @@ pass_optimize_bswap::execute (function *fun) variant wouldn't be detected. */ for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi);) { - gimple src_stmt, cur_stmt = gsi_stmt (gsi); + gimple ins_stmt, cur_stmt = gsi_stmt (gsi); tree fndecl = NULL_TREE, bswap_type = NULL_TREE, load_type; enum tree_code code; struct symbolic_number n; @@ -2518,9 +2534,9 @@ pass_optimize_bswap::execute (function *fun) continue; } - src_stmt = find_bswap_or_nop (cur_stmt, &n, &bswap); + ins_stmt = find_bswap_or_nop (cur_stmt, &n, &bswap); - if (!src_stmt) + if (!ins_stmt) continue; switch (n.range) @@ -2554,7 +2570,7 @@ pass_optimize_bswap::execute (function *fun) if (bswap && !fndecl && n.range != 16) continue; - if (bswap_replace (cur_stmt, src_stmt, fndecl, bswap_type, load_type, + if (bswap_replace (cur_stmt, ins_stmt, fndecl, bswap_type, load_type, &n, bswap)) changed = true; }