| Message ID | 20191001132709.87257-2-iii@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | S/390: Use signaling FP comparison instructions | expand |
On Tue, Oct 1, 2019 at 3:27 PM Ilya Leoshkevich <iii@linux.ibm.com> wrote: > > Right now gimplifier does not allow VEC_COND_EXPR's condition to trap > and introduces a temporary if this could happen, for example, generating > > _5 = _4 > { 2.0e+0, 2.0e+0, 2.0e+0, 2.0e+0 }; > _6 = VEC_COND_EXPR <_5, { -1, -1, -1, -1 }, { 0, 0, 0, 0 }>; > > from GENERIC > > VEC_COND_EXPR < (*b > { 2.0e+0, 2.0e+0, 2.0e+0, 2.0e+0 }) , > { -1, -1, -1, -1 } , > { 0, 0, 0, 0 } > > > This is not necessary and makes the resulting GIMPLE harder to analyze. > Change the gimplifier so as to allow COND_EXPR and VEC_COND_EXPR > conditions to trap. > > This patch takes special care to avoid introducing trapping comparisons > in GIMPLE_COND. They are not allowed, because they would require 3 > outgoing edges (then, else and EH), which is awkward to say the least. > Therefore, computations of such conditions should live in their own basic > blocks. OK. This can go in independently of the other changes in this series. Thanks and sorry for the delay. Richard. > gcc/ChangeLog: > > 2019-09-03 Ilya Leoshkevich <iii@linux.ibm.com> > > PR target/77918 > * gimple-expr.c (gimple_cond_get_ops_from_tree): Assert that the > caller passes a non-trapping condition. > (is_gimple_condexpr): Allow trapping conditions. > (is_gimple_condexpr_1): New helper function. > (is_gimple_condexpr_for_cond): New function, acts like old > is_gimple_condexpr. > * gimple-expr.h (is_gimple_condexpr_for_cond): New function. > * gimple.c (gimple_could_trap_p_1): Handle COND_EXPR and > VEC_COND_EXPR. Fix an issue with statements like i = (fp < 1.). > * gimplify.c (gimplify_cond_expr): Use > is_gimple_condexpr_for_cond. > (gimplify_expr): Allow is_gimple_condexpr_for_cond. > * tree-eh.c (operation_could_trap_p): Assert on COND_EXPR and > VEC_COND_EXPR. > (tree_could_trap_p): Handle COND_EXPR and VEC_COND_EXPR. > * tree-ssa-forwprop.c (forward_propagate_into_gimple_cond): Use > is_gimple_condexpr_for_cond, remove pointless tmp check > (forward_propagate_into_cond): Remove pointless tmp check. > --- > gcc/gimple-expr.c | 25 +++++++++++++++++++++---- > gcc/gimple-expr.h | 1 + > gcc/gimple.c | 14 +++++++++++++- > gcc/gimplify.c | 5 +++-- > gcc/tree-eh.c | 8 ++++++++ > gcc/tree-ssa-forwprop.c | 7 ++++--- > 6 files changed, 50 insertions(+), 10 deletions(-) > > diff --git a/gcc/gimple-expr.c b/gcc/gimple-expr.c > index 4082828e198..1738af186d7 100644 > --- a/gcc/gimple-expr.c > +++ b/gcc/gimple-expr.c > @@ -574,6 +574,7 @@ gimple_cond_get_ops_from_tree (tree cond, enum tree_code *code_p, > || TREE_CODE (cond) == TRUTH_NOT_EXPR > || is_gimple_min_invariant (cond) > || SSA_VAR_P (cond)); > + gcc_checking_assert (!tree_could_throw_p (cond)); > > extract_ops_from_tree (cond, code_p, lhs_p, rhs_p); > > @@ -605,17 +606,33 @@ is_gimple_lvalue (tree t) > || TREE_CODE (t) == BIT_FIELD_REF); > } > > -/* Return true if T is a GIMPLE condition. */ > +/* Helper for is_gimple_condexpr and is_gimple_condexpr_for_cond. */ > > -bool > -is_gimple_condexpr (tree t) > +static bool > +is_gimple_condexpr_1 (tree t, bool allow_traps) > { > return (is_gimple_val (t) || (COMPARISON_CLASS_P (t) > - && !tree_could_throw_p (t) > + && (allow_traps || !tree_could_throw_p (t)) > && is_gimple_val (TREE_OPERAND (t, 0)) > && is_gimple_val (TREE_OPERAND (t, 1)))); > } > > +/* Return true if T is a GIMPLE condition. */ > + > +bool > +is_gimple_condexpr (tree t) > +{ > + return is_gimple_condexpr_1 (t, true); > +} > + > +/* Like is_gimple_condexpr, but does not allow T to trap. */ > + > +bool > +is_gimple_condexpr_for_cond (tree t) > +{ > + return is_gimple_condexpr_1 (t, false); > +} > + > /* Return true if T is a gimple address. */ > > bool > diff --git a/gcc/gimple-expr.h b/gcc/gimple-expr.h > index 1ad1432bd17..0925aeb0f57 100644 > --- a/gcc/gimple-expr.h > +++ b/gcc/gimple-expr.h > @@ -41,6 +41,7 @@ extern void gimple_cond_get_ops_from_tree (tree, enum tree_code *, tree *, > tree *); > extern bool is_gimple_lvalue (tree); > extern bool is_gimple_condexpr (tree); > +extern bool is_gimple_condexpr_for_cond (tree); > extern bool is_gimple_address (const_tree); > extern bool is_gimple_invariant_address (const_tree); > extern bool is_gimple_ip_invariant_address (const_tree); > diff --git a/gcc/gimple.c b/gcc/gimple.c > index 8e828a5f169..a874c29454c 100644 > --- a/gcc/gimple.c > +++ b/gcc/gimple.c > @@ -2149,10 +2149,22 @@ gimple_could_trap_p_1 (gimple *s, bool include_mem, bool include_stores) > return false; > > case GIMPLE_ASSIGN: > - t = gimple_expr_type (s); > op = gimple_assign_rhs_code (s); > + > + /* For COND_EXPR and VEC_COND_EXPR only the condition may trap. */ > + if (op == COND_EXPR || op == VEC_COND_EXPR) > + return tree_could_trap_p (gimple_assign_rhs1 (s)); > + > + /* For comparisons we need to check rhs operand types instead of rhs type > + (which is BOOLEAN_TYPE). */ > + if (TREE_CODE_CLASS (op) == tcc_comparison) > + t = TREE_TYPE (gimple_assign_rhs1 (s)); > + else > + t = gimple_expr_type (s); > + > if (get_gimple_rhs_class (op) == GIMPLE_BINARY_RHS) > div = gimple_assign_rhs2 (s); > + > return (operation_could_trap_p (op, FLOAT_TYPE_P (t), > (INTEGRAL_TYPE_P (t) > && TYPE_OVERFLOW_TRAPS (t)), > diff --git a/gcc/gimplify.c b/gcc/gimplify.c > index 88d6571976f..836706961f3 100644 > --- a/gcc/gimplify.c > +++ b/gcc/gimplify.c > @@ -4142,8 +4142,8 @@ gimplify_cond_expr (tree *expr_p, gimple_seq *pre_p, fallback_t fallback) > /* Now do the normal gimplification. */ > > /* Gimplify condition. */ > - ret = gimplify_expr (&TREE_OPERAND (expr, 0), pre_p, NULL, is_gimple_condexpr, > - fb_rvalue); > + ret = gimplify_expr (&TREE_OPERAND (expr, 0), pre_p, NULL, > + is_gimple_condexpr_for_cond, fb_rvalue); > if (ret == GS_ERROR) > return GS_ERROR; > gcc_assert (TREE_OPERAND (expr, 0) != NULL_TREE); > @@ -12976,6 +12976,7 @@ gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p, > else if (gimple_test_f == is_gimple_val > || gimple_test_f == is_gimple_call_addr > || gimple_test_f == is_gimple_condexpr > + || gimple_test_f == is_gimple_condexpr_for_cond > || gimple_test_f == is_gimple_mem_rhs > || gimple_test_f == is_gimple_mem_rhs_or_call > || gimple_test_f == is_gimple_reg_rhs > diff --git a/gcc/tree-eh.c b/gcc/tree-eh.c > index 5bb07e49d28..b3722ba8839 100644 > --- a/gcc/tree-eh.c > +++ b/gcc/tree-eh.c > @@ -2523,6 +2523,10 @@ operation_could_trap_p (enum tree_code op, bool fp_operation, bool honor_trapv, > bool honor_snans = fp_operation && flag_signaling_nans != 0; > bool handled; > > + /* This function cannot tell whether or not COND_EXPR and VEC_COND_EXPR could > + trap, because that depends on the respective condition op. */ > + gcc_assert (op != COND_EXPR && op != VEC_COND_EXPR); > + > if (TREE_CODE_CLASS (op) != tcc_comparison > && TREE_CODE_CLASS (op) != tcc_unary > && TREE_CODE_CLASS (op) != tcc_binary) > @@ -2610,6 +2614,10 @@ tree_could_trap_p (tree expr) > if (!expr) > return false; > > + /* For COND_EXPR and VEC_COND_EXPR only the condition may trap. */ > + if (TREE_CODE (expr) == COND_EXPR || TREE_CODE (expr) == VEC_COND_EXPR) > + expr = TREE_OPERAND (expr, 0); > + > code = TREE_CODE (expr); > t = TREE_TYPE (expr); > > diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c > index 221f140b356..0d1c066b354 100644 > --- a/gcc/tree-ssa-forwprop.c > +++ b/gcc/tree-ssa-forwprop.c > @@ -527,9 +527,10 @@ forward_propagate_into_gimple_cond (gcond *stmt) > tmp = forward_propagate_into_comparison_1 (stmt, code, > boolean_type_node, > rhs1, rhs2); > - if (tmp) > + if (tmp > + && is_gimple_condexpr_for_cond (tmp)) > { > - if (dump_file && tmp) > + if (dump_file) > { > fprintf (dump_file, " Replaced '"); > print_gimple_expr (dump_file, stmt, 0); > @@ -607,7 +608,7 @@ forward_propagate_into_cond (gimple_stmt_iterator *gsi_p) > if (tmp > && is_gimple_condexpr (tmp)) > { > - if (dump_file && tmp) > + if (dump_file) > { > fprintf (dump_file, " Replaced '"); > print_generic_expr (dump_file, cond); > -- > 2.23.0 >
diff --git a/gcc/gimple-expr.c b/gcc/gimple-expr.c index 4082828e198..1738af186d7 100644 --- a/gcc/gimple-expr.c +++ b/gcc/gimple-expr.c @@ -574,6 +574,7 @@ gimple_cond_get_ops_from_tree (tree cond, enum tree_code *code_p, || TREE_CODE (cond) == TRUTH_NOT_EXPR || is_gimple_min_invariant (cond) || SSA_VAR_P (cond)); + gcc_checking_assert (!tree_could_throw_p (cond)); extract_ops_from_tree (cond, code_p, lhs_p, rhs_p); @@ -605,17 +606,33 @@ is_gimple_lvalue (tree t) || TREE_CODE (t) == BIT_FIELD_REF); } -/* Return true if T is a GIMPLE condition. */ +/* Helper for is_gimple_condexpr and is_gimple_condexpr_for_cond. */ -bool -is_gimple_condexpr (tree t) +static bool +is_gimple_condexpr_1 (tree t, bool allow_traps) { return (is_gimple_val (t) || (COMPARISON_CLASS_P (t) - && !tree_could_throw_p (t) + && (allow_traps || !tree_could_throw_p (t)) && is_gimple_val (TREE_OPERAND (t, 0)) && is_gimple_val (TREE_OPERAND (t, 1)))); } +/* Return true if T is a GIMPLE condition. */ + +bool +is_gimple_condexpr (tree t) +{ + return is_gimple_condexpr_1 (t, true); +} + +/* Like is_gimple_condexpr, but does not allow T to trap. */ + +bool +is_gimple_condexpr_for_cond (tree t) +{ + return is_gimple_condexpr_1 (t, false); +} + /* Return true if T is a gimple address. */ bool diff --git a/gcc/gimple-expr.h b/gcc/gimple-expr.h index 1ad1432bd17..0925aeb0f57 100644 --- a/gcc/gimple-expr.h +++ b/gcc/gimple-expr.h @@ -41,6 +41,7 @@ extern void gimple_cond_get_ops_from_tree (tree, enum tree_code *, tree *, tree *); extern bool is_gimple_lvalue (tree); extern bool is_gimple_condexpr (tree); +extern bool is_gimple_condexpr_for_cond (tree); extern bool is_gimple_address (const_tree); extern bool is_gimple_invariant_address (const_tree); extern bool is_gimple_ip_invariant_address (const_tree); diff --git a/gcc/gimple.c b/gcc/gimple.c index 8e828a5f169..a874c29454c 100644 --- a/gcc/gimple.c +++ b/gcc/gimple.c @@ -2149,10 +2149,22 @@ gimple_could_trap_p_1 (gimple *s, bool include_mem, bool include_stores) return false; case GIMPLE_ASSIGN: - t = gimple_expr_type (s); op = gimple_assign_rhs_code (s); + + /* For COND_EXPR and VEC_COND_EXPR only the condition may trap. */ + if (op == COND_EXPR || op == VEC_COND_EXPR) + return tree_could_trap_p (gimple_assign_rhs1 (s)); + + /* For comparisons we need to check rhs operand types instead of rhs type + (which is BOOLEAN_TYPE). */ + if (TREE_CODE_CLASS (op) == tcc_comparison) + t = TREE_TYPE (gimple_assign_rhs1 (s)); + else + t = gimple_expr_type (s); + if (get_gimple_rhs_class (op) == GIMPLE_BINARY_RHS) div = gimple_assign_rhs2 (s); + return (operation_could_trap_p (op, FLOAT_TYPE_P (t), (INTEGRAL_TYPE_P (t) && TYPE_OVERFLOW_TRAPS (t)), diff --git a/gcc/gimplify.c b/gcc/gimplify.c index 88d6571976f..836706961f3 100644 --- a/gcc/gimplify.c +++ b/gcc/gimplify.c @@ -4142,8 +4142,8 @@ gimplify_cond_expr (tree *expr_p, gimple_seq *pre_p, fallback_t fallback) /* Now do the normal gimplification. */ /* Gimplify condition. */ - ret = gimplify_expr (&TREE_OPERAND (expr, 0), pre_p, NULL, is_gimple_condexpr, - fb_rvalue); + ret = gimplify_expr (&TREE_OPERAND (expr, 0), pre_p, NULL, + is_gimple_condexpr_for_cond, fb_rvalue); if (ret == GS_ERROR) return GS_ERROR; gcc_assert (TREE_OPERAND (expr, 0) != NULL_TREE); @@ -12976,6 +12976,7 @@ gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p, else if (gimple_test_f == is_gimple_val || gimple_test_f == is_gimple_call_addr || gimple_test_f == is_gimple_condexpr + || gimple_test_f == is_gimple_condexpr_for_cond || gimple_test_f == is_gimple_mem_rhs || gimple_test_f == is_gimple_mem_rhs_or_call || gimple_test_f == is_gimple_reg_rhs diff --git a/gcc/tree-eh.c b/gcc/tree-eh.c index 5bb07e49d28..b3722ba8839 100644 --- a/gcc/tree-eh.c +++ b/gcc/tree-eh.c @@ -2523,6 +2523,10 @@ operation_could_trap_p (enum tree_code op, bool fp_operation, bool honor_trapv, bool honor_snans = fp_operation && flag_signaling_nans != 0; bool handled; + /* This function cannot tell whether or not COND_EXPR and VEC_COND_EXPR could + trap, because that depends on the respective condition op. */ + gcc_assert (op != COND_EXPR && op != VEC_COND_EXPR); + if (TREE_CODE_CLASS (op) != tcc_comparison && TREE_CODE_CLASS (op) != tcc_unary && TREE_CODE_CLASS (op) != tcc_binary) @@ -2610,6 +2614,10 @@ tree_could_trap_p (tree expr) if (!expr) return false; + /* For COND_EXPR and VEC_COND_EXPR only the condition may trap. */ + if (TREE_CODE (expr) == COND_EXPR || TREE_CODE (expr) == VEC_COND_EXPR) + expr = TREE_OPERAND (expr, 0); + code = TREE_CODE (expr); t = TREE_TYPE (expr); diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c index 221f140b356..0d1c066b354 100644 --- a/gcc/tree-ssa-forwprop.c +++ b/gcc/tree-ssa-forwprop.c @@ -527,9 +527,10 @@ forward_propagate_into_gimple_cond (gcond *stmt) tmp = forward_propagate_into_comparison_1 (stmt, code, boolean_type_node, rhs1, rhs2); - if (tmp) + if (tmp + && is_gimple_condexpr_for_cond (tmp)) { - if (dump_file && tmp) + if (dump_file) { fprintf (dump_file, " Replaced '"); print_gimple_expr (dump_file, stmt, 0); @@ -607,7 +608,7 @@ forward_propagate_into_cond (gimple_stmt_iterator *gsi_p) if (tmp && is_gimple_condexpr (tmp)) { - if (dump_file && tmp) + if (dump_file) { fprintf (dump_file, " Replaced '"); print_generic_expr (dump_file, cond);
Right now gimplifier does not allow VEC_COND_EXPR's condition to trap and introduces a temporary if this could happen, for example, generating _5 = _4 > { 2.0e+0, 2.0e+0, 2.0e+0, 2.0e+0 }; _6 = VEC_COND_EXPR <_5, { -1, -1, -1, -1 }, { 0, 0, 0, 0 }>; from GENERIC VEC_COND_EXPR < (*b > { 2.0e+0, 2.0e+0, 2.0e+0, 2.0e+0 }) , { -1, -1, -1, -1 } , { 0, 0, 0, 0 } > This is not necessary and makes the resulting GIMPLE harder to analyze. Change the gimplifier so as to allow COND_EXPR and VEC_COND_EXPR conditions to trap. This patch takes special care to avoid introducing trapping comparisons in GIMPLE_COND. They are not allowed, because they would require 3 outgoing edges (then, else and EH), which is awkward to say the least. Therefore, computations of such conditions should live in their own basic blocks. gcc/ChangeLog: 2019-09-03 Ilya Leoshkevich <iii@linux.ibm.com> PR target/77918 * gimple-expr.c (gimple_cond_get_ops_from_tree): Assert that the caller passes a non-trapping condition. (is_gimple_condexpr): Allow trapping conditions. (is_gimple_condexpr_1): New helper function. (is_gimple_condexpr_for_cond): New function, acts like old is_gimple_condexpr. * gimple-expr.h (is_gimple_condexpr_for_cond): New function. * gimple.c (gimple_could_trap_p_1): Handle COND_EXPR and VEC_COND_EXPR. Fix an issue with statements like i = (fp < 1.). * gimplify.c (gimplify_cond_expr): Use is_gimple_condexpr_for_cond. (gimplify_expr): Allow is_gimple_condexpr_for_cond. * tree-eh.c (operation_could_trap_p): Assert on COND_EXPR and VEC_COND_EXPR. (tree_could_trap_p): Handle COND_EXPR and VEC_COND_EXPR. * tree-ssa-forwprop.c (forward_propagate_into_gimple_cond): Use is_gimple_condexpr_for_cond, remove pointless tmp check (forward_propagate_into_cond): Remove pointless tmp check. --- gcc/gimple-expr.c | 25 +++++++++++++++++++++---- gcc/gimple-expr.h | 1 + gcc/gimple.c | 14 +++++++++++++- gcc/gimplify.c | 5 +++-- gcc/tree-eh.c | 8 ++++++++ gcc/tree-ssa-forwprop.c | 7 ++++--- 6 files changed, 50 insertions(+), 10 deletions(-)