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 <[email protected]>
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
