Here is a patch to fix to teach tree-ssa-reassoc the sinking the cast.
Bootstrapped and regression tested on x86-64-none-linux-gnu with no new
regressions. Also regression tested on qemu arm.
I also verified the issue Andreas Schwab raised is fixed on arm
cortex-a5 where the same issue was present. Does this make sense?
Thanks,
Kugan
gcc/ChangeLog:
2015-07-15 Kugan Vivekanandarajah <kug...@linaro.org>
PR middle-end/66726
* tree-ssa-reassoc.c (optimize_range_tests): Handle sinking the cast
after PHI.
(final_range_test_p): Detect sinking the cast after PHI.
(maybe_optimize_range_tests): Handle sinking the cast after PHI.
diff --git a/gcc/tree-ssa-reassoc.c b/gcc/tree-ssa-reassoc.c
index 932c83a..3058eb5 100644
--- a/gcc/tree-ssa-reassoc.c
+++ b/gcc/tree-ssa-reassoc.c
@@ -2707,18 +2707,32 @@ optimize_range_tests (enum tree_code opcode,
# _345 = PHI <_123(N), 1(...), 1(...)>
where _234 has bool type, _123 has single use and
bb N has a single successor M. This is commonly used in
- the last block of a range test. */
+ the last block of a range test.
+
+ Also Return true if STMT is tcc_compare like:
+ <bb N>:
+ ...
+ _234 = a_2(D) == 2;
+ <bb M>:
+ # _345 = PHI <_234(N), 1(...), 1(...)>
+ _346 = (int) _345;
+ where _234 has booltype, single use and
+ bb N has a single successor M. This is commonly used in
+ the last block of a range test. */
static bool
final_range_test_p (gimple stmt)
{
- basic_block bb, rhs_bb;
+ basic_block bb, rhs_bb, lhs_bb;
edge e;
tree lhs, rhs;
use_operand_p use_p;
gimple use_stmt;
- if (!gimple_assign_cast_p (stmt))
+ if (!gimple_assign_cast_p (stmt)
+ && (!is_gimple_assign (stmt)
+ || (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt))
+ != tcc_comparison)))
return false;
bb = gimple_bb (stmt);
if (!single_succ_p (bb))
@@ -2729,9 +2743,8 @@ final_range_test_p (gimple stmt)
lhs = gimple_assign_lhs (stmt);
rhs = gimple_assign_rhs1 (stmt);
- if (!INTEGRAL_TYPE_P (TREE_TYPE (lhs))
- || TREE_CODE (rhs) != SSA_NAME
- || TREE_CODE (TREE_TYPE (rhs)) != BOOLEAN_TYPE)
+ if (TREE_CODE (TREE_TYPE (rhs)) != BOOLEAN_TYPE
+ && TREE_CODE (TREE_TYPE (lhs)) != BOOLEAN_TYPE)
return false;
/* Test whether lhs is consumed only by a PHI in the only successor bb. */
@@ -2743,10 +2756,21 @@ final_range_test_p (gimple stmt)
return false;
/* And that the rhs is defined in the same loop. */
- rhs_bb = gimple_bb (SSA_NAME_DEF_STMT (rhs));
- if (rhs_bb == NULL
- || !flow_bb_inside_loop_p (loop_containing_stmt (stmt), rhs_bb))
- return false;
+ if (gimple_assign_cast_p (stmt))
+ {
+ if (!INTEGRAL_TYPE_P (TREE_TYPE (lhs))
+ || TREE_CODE (rhs) != SSA_NAME
+ || !(rhs_bb = gimple_bb (SSA_NAME_DEF_STMT (rhs)))
+ || !flow_bb_inside_loop_p (loop_containing_stmt (stmt), rhs_bb))
+ return false;
+ }
+ else
+ {
+ if (TREE_CODE (lhs) != SSA_NAME
+ || !(lhs_bb = gimple_bb (SSA_NAME_DEF_STMT (lhs)))
+ || !flow_bb_inside_loop_p (loop_containing_stmt (stmt), lhs_bb))
+ return false;
+ }
return true;
}
@@ -3132,6 +3156,8 @@ maybe_optimize_range_tests (gimple stmt)
/* stmt is
_123 = (int) _234;
+ OR
+ _234 = a_2(D) == 2;
followed by:
<bb M>:
@@ -3161,6 +3187,8 @@ maybe_optimize_range_tests (gimple stmt)
of the bitwise or resp. and, recursively. */
if (!get_ops (rhs, code, &ops,
loop_containing_stmt (stmt))
+ && (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt))
+ != tcc_comparison)
&& has_single_use (rhs))
{
/* Otherwise, push the _234 range test itself. */
@@ -3173,6 +3201,22 @@ maybe_optimize_range_tests (gimple stmt)
ops.safe_push (oe);
bb_ent.last_idx++;
}
+ else if (!get_ops (lhs, code, &ops,
+ loop_containing_stmt (stmt))
+ && is_gimple_assign (stmt)
+ && (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt))
+ == tcc_comparison)
+ && has_single_use (lhs))
+ {
+ /* Push the _234 range test itself. */
+ operand_entry_t oe = operand_entry_pool.allocate ();
+ oe->op = lhs;
+ oe->rank = code;
+ oe->id = 0;
+ oe->count = 1;
+ ops.safe_push (oe);
+ bb_ent.last_idx++;
+ }
else
bb_ent.last_idx = ops.length ();
bb_ent.op = rhs;
@@ -3267,7 +3311,8 @@ maybe_optimize_range_tests (gimple stmt)
else if (gimple_assign_cast_p (use_stmt))
cast_stmt = use_stmt;
else
- gcc_unreachable ();
+ cast_stmt = NULL;
+
if (cast_stmt)
{
gcc_assert (bb == last_bb);
