From 78f29aa30d9fe1a73e6fa961dafe1871f508f061 Mon Sep 17 00:00:00 2001 From: fjahanian Date: Tue, 12 Oct 2004 20:50:08 +0000 Subject: [PATCH] PR 17892. OKed by Roger Sayle. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@88950 138bc75d-0d04-0410-961f-82ee72b054a4 --- gcc/ChangeLog | 8 ++++++++ .../gcc.c-torture/execute/ieee/unsafe-fp-assoc.c | 19 +++++++++++++++++++ gcc/tree-outof-ssa.c | 8 ++++++++ gcc/tree-ssa-dom.c | 15 ++++++++++++++- 4 files changed, 49 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.c-torture/execute/ieee/unsafe-fp-assoc.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index a6050279f9f..4e3bba79196 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2004-10-12 Fariborz Jahanian + + PR 17892 + * tree-ssa-dom.c (unsafe_associative_fp_binop): New function. + (simplify_rhs_and_lookup_avail_expr): Disallow associativity + and constant folding of floating point MULT_EXPR/PLUS_EXPR + expressions. + 2004-10-12 Ulrich Weigand * config/s390/s390.c (s390_va_start): Use build_va_arg_indirect_ref. diff --git a/gcc/testsuite/gcc.c-torture/execute/ieee/unsafe-fp-assoc.c b/gcc/testsuite/gcc.c-torture/execute/ieee/unsafe-fp-assoc.c new file mode 100644 index 00000000000..d67fef02321 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/ieee/unsafe-fp-assoc.c @@ -0,0 +1,19 @@ +#include + +extern void abort(void); + +static const double C = DBL_MAX; + +double foo(double x) +{ + return ( ( (x * C) * C ) * C); +} + +int main () +{ + double d = foo (0.0); + if (d != 0.0) + abort (); + + return 0; +} diff --git a/gcc/tree-outof-ssa.c b/gcc/tree-outof-ssa.c index 827f91d1511..a99f03d0121 100644 --- a/gcc/tree-outof-ssa.c +++ b/gcc/tree-outof-ssa.c @@ -1634,12 +1634,20 @@ find_replaceable_in_bb (temp_expr_table_p tab, basic_block bb) var_map map = tab->map; value_expr_p p; ssa_op_iter iter; + bitmap_iterator bi; for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) { stmt = bsi_stmt (bsi); ann = stmt_ann (stmt); + if (TREE_CODE (stmt) == ASM_EXPR && ASM_VOLATILE_P (stmt)) + { + /* Volatile ASM_EXPRs kill all current expressions. */ + EXECUTE_IF_SET_IN_BITMAP ((tab->partition_in_use), 0, partition, bi) + kill_expr (tab, partition, false); + continue; + } /* Determine if this stmt finishes an existing expression. */ FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_USE) { diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c index 5d545bd2a26..4ab36138f65 100644 --- a/gcc/tree-ssa-dom.c +++ b/gcc/tree-ssa-dom.c @@ -266,6 +266,7 @@ static void restore_currdefs_to_original_value (void); static void register_definitions_for_stmt (tree); static edge single_incoming_edge_ignoring_loop_edges (basic_block); static void restore_nonzero_vars_to_original_value (void); +static inline bool unsafe_associative_fp_binop (tree); /* Local version of fold that doesn't introduce cruft. */ @@ -1549,6 +1550,18 @@ record_equality (tree x, tree y) record_const_or_copy_1 (x, y, prev_x); } +/* Return true, if it is ok to do folding of an associative expression. + EXP is the tree for the associative expression. */ + +static inline bool +unsafe_associative_fp_binop (tree exp) +{ + enum tree_code code = TREE_CODE (exp); + return !(!flag_unsafe_math_optimizations + && (code == MULT_EXPR || code == PLUS_EXPR) + && FLOAT_TYPE_P (TREE_TYPE (exp))); +} + /* STMT is a MODIFY_EXPR for which we were unable to find RHS in the hash tables. Try to simplify the RHS using whatever equivalences we may have recorded. @@ -1608,7 +1621,7 @@ simplify_rhs_and_lookup_avail_expr (struct dom_walk_data *walk_data, tree rhs_def_rhs = TREE_OPERAND (rhs_def_stmt, 1); enum tree_code rhs_def_code = TREE_CODE (rhs_def_rhs); - if (rhs_code == rhs_def_code + if ((rhs_code == rhs_def_code && unsafe_associative_fp_binop (rhs)) || (rhs_code == PLUS_EXPR && rhs_def_code == MINUS_EXPR) || (rhs_code == MINUS_EXPR && rhs_def_code == PLUS_EXPR)) { -- 2.11.4.GIT