===================================================================
@@ -288,45 +288,48 @@ recognize_bits_test (gimple cond, tree *
|| gimple_assign_rhs_code (stmt) != BIT_AND_EXPR)
return false;
*name = get_name_for_bit_test (gimple_assign_rhs1 (stmt));
*bits = gimple_assign_rhs2 (stmt);
return true;
}
/* If-convert on a and pattern with a common else block. The inner
- if is specified by its INNER_COND_BB, the outer by OUTER_COND_BB.
+ if is specified by its INNER_COND_BB, the outer by OUTER_COND_BB,
+ negated if outer_inv is true.
Returns true if the edges to the common else basic-block were merged. */
static bool
-ifcombine_ifandif (basic_block inner_cond_bb, basic_block outer_cond_bb)
+ifcombine_ifandif (basic_block inner_cond_bb, basic_block outer_cond_bb,
+ bool outer_inv)
{
gimple_stmt_iterator gsi;
gimple inner_cond, outer_cond;
tree name1, name2, bit1, bit2;
inner_cond = last_stmt (inner_cond_bb);
if (!inner_cond
|| gimple_code (inner_cond) != GIMPLE_COND)
return false;
outer_cond = last_stmt (outer_cond_bb);
if (!outer_cond
|| gimple_code (outer_cond) != GIMPLE_COND)
return false;
/* See if we test a single bit of the same name in both tests. In
that case remove the outer test, merging both else edges,
and change the inner one to test for
name & (bit1 | bit2) == (bit1 | bit2). */
- if (recognize_single_bit_test (inner_cond, &name1, &bit1)
+ if (!outer_inv
+ && recognize_single_bit_test (inner_cond, &name1, &bit1)
&& recognize_single_bit_test (outer_cond, &name2, &bit2)
&& name1 == name2)
{
tree t, t2;
/* Do it. */
gsi = gsi_for_stmt (inner_cond);
t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1),
build_int_cst (TREE_TYPE (name1), 1), bit1);
t2 = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1),
@@ -360,76 +363,86 @@ ifcombine_ifandif (basic_block inner_con
}
return true;
}
/* See if we have two comparisons that we can merge into one. */
else if (TREE_CODE_CLASS (gimple_cond_code (inner_cond)) == tcc_comparison
&& TREE_CODE_CLASS (gimple_cond_code (outer_cond)) == tcc_comparison)
{
tree t;
+ enum tree_code outer_cond_code = gimple_cond_code (outer_cond);
+ if (outer_inv)
+ outer_cond_code = invert_tree_comparison (outer_cond_code,
+ HONOR_NANS (TYPE_MODE (TREE_TYPE (gimple_cond_lhs (outer_cond)))));
+ if (outer_cond_code == ERROR_MARK)
+ return false;
if (!(t = maybe_fold_and_comparisons (gimple_cond_code (inner_cond),
gimple_cond_lhs (inner_cond),
gimple_cond_rhs (inner_cond),
- gimple_cond_code (outer_cond),
+ outer_cond_code,
gimple_cond_lhs (outer_cond),
gimple_cond_rhs (outer_cond))))
return false;
t = canonicalize_cond_expr_cond (t);
if (!t)
return false;
gimple_cond_set_condition_from_tree (inner_cond, t);
update_stmt (inner_cond);
/* Leave CFG optimization to cfg_cleanup. */
- gimple_cond_set_condition_from_tree (outer_cond, boolean_true_node);
+ gimple_cond_set_condition_from_tree (outer_cond,
+ outer_inv ? boolean_false_node : boolean_true_node);
update_stmt (outer_cond);
if (dump_file)
{
fprintf (dump_file, "optimizing two comparisons to ");
print_generic_expr (dump_file, t, 0);
fprintf (dump_file, "\n");
}
return true;
}
return false;
}
/* If-convert on a or pattern with a common then block. The inner
- if is specified by its INNER_COND_BB, the outer by OUTER_COND_BB.
+ if is specified by its INNER_COND_BB, the outer by OUTER_COND_BB,
+ negated if outer_inv is true.
Returns true, if the edges leading to the common then basic-block
were merged. */
static bool
-ifcombine_iforif (basic_block inner_cond_bb, basic_block outer_cond_bb)
+ifcombine_iforif (basic_block inner_cond_bb, basic_block outer_cond_bb,
+ bool outer_inv)
{
gimple inner_cond, outer_cond;
tree name1, name2, bits1, bits2;
inner_cond = last_stmt (inner_cond_bb);
if (!inner_cond
|| gimple_code (inner_cond) != GIMPLE_COND)
return false;
outer_cond = last_stmt (outer_cond_bb);
if (!outer_cond
|| gimple_code (outer_cond) != GIMPLE_COND)
return false;
/* See if we have two bit tests of the same name in both tests.
In that case remove the outer test and change the inner one to
test for name & (bits1 | bits2) != 0. */
- if (recognize_bits_test (inner_cond, &name1, &bits1)
+ if (!outer_inv
+ && recognize_bits_test (inner_cond, &name1, &bits1)
&& recognize_bits_test (outer_cond, &name2, &bits2))
{
gimple_stmt_iterator gsi;
tree t;
/* Find the common name which is bit-tested. */
if (name1 == name2)
;
else if (bits1 == bits2)
{
@@ -508,36 +521,43 @@ ifcombine_iforif (basic_block inner_cond
return true;
}
/* See if we have two comparisons that we can merge into one.
This happens for C++ operator overloading where for example
GE_EXPR is implemented as GT_EXPR || EQ_EXPR. */
else if (TREE_CODE_CLASS (gimple_cond_code (inner_cond)) == tcc_comparison
&& TREE_CODE_CLASS (gimple_cond_code (outer_cond)) == tcc_comparison)
{
tree t;
+ enum tree_code outer_cond_code = gimple_cond_code (outer_cond);
+ if (outer_inv)
+ outer_cond_code = invert_tree_comparison (outer_cond_code,
+ HONOR_NANS (TYPE_MODE (TREE_TYPE (gimple_cond_lhs (outer_cond)))));
+ if (outer_cond_code == ERROR_MARK)
+ return false;
if (!(t = maybe_fold_or_comparisons (gimple_cond_code (inner_cond),
gimple_cond_lhs (inner_cond),
gimple_cond_rhs (inner_cond),
- gimple_cond_code (outer_cond),
+ outer_cond_code,
gimple_cond_lhs (outer_cond),
gimple_cond_rhs (outer_cond))))
return false;
t = canonicalize_cond_expr_cond (t);
if (!t)
return false;
gimple_cond_set_condition_from_tree (inner_cond, t);
update_stmt (inner_cond);
/* Leave CFG optimization to cfg_cleanup. */
- gimple_cond_set_condition_from_tree (outer_cond, boolean_false_node);
+ gimple_cond_set_condition_from_tree (outer_cond,
+ outer_inv ? boolean_true_node : boolean_false_node);
update_stmt (outer_cond);
if (dump_file)
{
fprintf (dump_file, "optimizing two comparisons to ");
print_generic_expr (dump_file, t, 0);
fprintf (dump_file, "\n");
}
return true;
@@ -580,40 +600,73 @@ tree_ssa_ifcombine_bb (basic_block inner
{
/* We have
<outer_cond_bb>
if (q) goto inner_cond_bb; else goto else_bb;
<inner_cond_bb>
if (p) goto ...; else goto else_bb;
...
<else_bb>
...
*/
- return ifcombine_ifandif (inner_cond_bb, outer_cond_bb);
+ return ifcombine_ifandif (inner_cond_bb, outer_cond_bb, false);
+ }
+
+ /* And a version where the outer condition is negated. */
+ if (recognize_if_then_else (outer_cond_bb, &else_bb, &inner_cond_bb)
+ && same_phi_args_p (outer_cond_bb, inner_cond_bb, else_bb)
+ && bb_no_side_effects_p (inner_cond_bb))
+ {
+ /* We have
+ <outer_cond_bb>
+ if (q) goto else_bb; else goto inner_cond_bb;
+ <inner_cond_bb>
+ if (p) goto ...; else goto else_bb;
+ ...
+ <else_bb>
+ ...
+ */
+ return ifcombine_ifandif (inner_cond_bb, outer_cond_bb, true);
}
/* The || form is characterized by a common then_bb with the
two edges leading to it mergable. The latter is guaranteed
by matching PHI arguments in the then_bb and the inner cond_bb
having no side-effects. */
if (recognize_if_then_else (outer_cond_bb, &then_bb, &inner_cond_bb)
&& same_phi_args_p (outer_cond_bb, inner_cond_bb, then_bb)
&& bb_no_side_effects_p (inner_cond_bb))
{
/* We have
<outer_cond_bb>
if (q) goto then_bb; else goto inner_cond_bb;
<inner_cond_bb>
if (q) goto then_bb; else goto ...;
<then_bb>
...
*/
- return ifcombine_iforif (inner_cond_bb, outer_cond_bb);
+ return ifcombine_iforif (inner_cond_bb, outer_cond_bb, false);
+ }
+
+ /* And a version where the outer condition is negated. */
+ if (recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &then_bb)
+ && same_phi_args_p (outer_cond_bb, inner_cond_bb, then_bb)
+ && bb_no_side_effects_p (inner_cond_bb))
+ {
+ /* We have
+ <outer_cond_bb>
+ if (q) goto inner_cond_bb; else goto then_bb;
+ <inner_cond_bb>
+ if (q) goto then_bb; else goto ...;
+ <then_bb>
+ ...
+ */
+ return ifcombine_iforif (inner_cond_bb, outer_cond_bb, true);
}
}
return false;
}
/* Main entry for the tree if-conversion pass. */
static unsigned int
tree_ssa_ifcombine (void)
===================================================================
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-trapping-math -fdump-tree-ifcombine" } */
+
+void f ();
+enum Sign { NEG=-1, ZERO, POS };
+
+static inline enum Sign sign (double x)
+{
+ if (x > 0) return POS;
+ if (x < 0) return NEG;
+ return ZERO;
+}
+void g (double x)
+{
+ if (sign (x) == NEG) f();
+}
+
+/* The above should be optimized to x < 0 by ifcombine.
+ The transformation would also be legal with -ftrapping-math. */
+
+/* { dg-final { scan-tree-dump "optimizing.* < " "ifcombine" } } */
+/* { dg-final { cleanup-tree-dump "ifcombine" } } */
Property changes on: testsuite/gcc.dg/tree-ssa/ssa-ifcombine-9.c
___________________________________________________________________
Added: svn:keywords
+ Author Date Id Revision URL
Added: svn:eol-style
+ native
===================================================================
@@ -0,0 +1,25 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fno-trapping-math -fdump-tree-ifcombine" } */
+
+double test1 (double i, double j)
+{
+ if (i >= j)
+ if (i <= j)
+ goto plif;
+ else
+ goto plouf;
+ else
+ goto plif;
+
+plif:
+ return 0;
+plouf:
+ return -1;
+}
+
+/* The above should be optimized to a i > j test by ifcombine.
+ The transformation would also be legal with -ftrapping-math.
+ Instead we get u<=, which is acceptable with -fno-trapping-math. */
+
+/* { dg-final { scan-tree-dump " u<= " "ifcombine" } } */
+/* { dg-final { cleanup-tree-dump "ifcombine" } } */