Hi!
The following patch improves code generation on the included testcase by
enabling two_value_replacement on booleans. It does that only for arg0/arg1
values that conditional_replacement doesn't handle, and only does it if not
in the early phiopt pass, because conditional_replacement isn't done early
either.
I must say I'm not sure about that, in PR87105 / PR87608 you've added the
early phiopt pass and specifically excluded conditional_replacement and a
few others from being optimized early, but then 3 months later I've added
two_value_replacement and didn't restrict it to !early_p. Shall we instead
do two_value_replacement only in late phiopt?
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2020-12-05 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/96232
* tree-ssa-phiopt.c (two_value_replacement): Add early_p argument.
If false, optimize even boolean lhs cases as long as arg0 has wider
precision and conditional_replacement doesn't handle that case.
* gcc.dg/tree-ssa/pr96232-2.c: New test.
--- gcc/tree-ssa-phiopt.c.jj 2020-12-04 17:27:53.472837921 +0100
+++ gcc/tree-ssa-phiopt.c 2020-12-04 17:54:56.070689584 +0100
@@ -51,7 +51,7 @@ along with GCC; see the file COPYING3.
static unsigned int tree_ssa_phiopt_worker (bool, bool, bool);
static bool two_value_replacement (basic_block, basic_block, edge, gphi *,
- tree, tree);
+ tree, tree, bool);
static bool conditional_replacement (basic_block, basic_block,
edge, edge, gphi *, tree, tree);
static gphi *factor_out_conditional_conversion (edge, edge, gphi *, tree, tree,
@@ -337,7 +337,7 @@ tree_ssa_phiopt_worker (bool do_store_el
}
/* Do the replacement of conditional if it can be done. */
- if (two_value_replacement (bb, bb1, e2, phi, arg0, arg1))
+ if (two_value_replacement (bb, bb1, e2, phi, arg0, arg1, early_p))
cfgchanged = true;
else if (!early_p
&& conditional_replacement (bb, bb1, e1, e2, phi,
@@ -614,7 +614,7 @@ factor_out_conditional_conversion (edge
static bool
two_value_replacement (basic_block cond_bb, basic_block middle_bb,
- edge e1, gphi *phi, tree arg0, tree arg1)
+ edge e1, gphi *phi, tree arg0, tree arg1, bool early_p)
{
/* Only look for adjacent integer constants. */
if (!INTEGRAL_TYPE_P (TREE_TYPE (arg0))
@@ -635,7 +635,7 @@ two_value_replacement (basic_block cond_
if (TREE_CODE (lhs) != SSA_NAME
|| !INTEGRAL_TYPE_P (TREE_TYPE (lhs))
- || TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE
+ || (early_p && TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE)
|| TREE_CODE (rhs) != INTEGER_CST)
return false;
@@ -648,9 +648,25 @@ two_value_replacement (basic_block cond_
return false;
}
+ /* Defer boolean x ? 0 : {1,-1} or x ? {1,-1} : 0 to
+ conditional_replacement. */
+ if (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE
+ && (integer_zerop (arg0)
+ || integer_zerop (arg1)
+ || TREE_CODE (TREE_TYPE (arg0)) == BOOLEAN_TYPE
+ || (TYPE_PRECISION (TREE_TYPE (arg0))
+ <= TYPE_PRECISION (TREE_TYPE (lhs)))))
+ return false;
+
wide_int min, max;
- if (get_range_info (lhs, &min, &max) != VR_RANGE
- || min + 1 != max
+ if (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE)
+ {
+ min = wi::to_wide (boolean_false_node);
+ max = wi::to_wide (boolean_true_node);
+ }
+ else if (get_range_info (lhs, &min, &max) != VR_RANGE)
+ return false;
+ if (min + 1 != max
|| (wi::to_wide (rhs) != min
&& wi::to_wide (rhs) != max))
return false;
--- gcc/testsuite/gcc.dg/tree-ssa/pr96232-2.c.jj 2020-12-04
17:56:22.180730234 +0100
+++ gcc/testsuite/gcc.dg/tree-ssa/pr96232-2.c 2020-12-04 17:57:27.973997239
+0100
@@ -0,0 +1,18 @@
+/* PR tree-optimization/96232 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump " 38 - " "optimized" } } */
+/* { dg-final { scan-tree-dump " \\+ 97;" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "PHI <" "optimized" } } */
+
+int
+foo (_Bool x)
+{
+ return x ? 37 : 38;
+}
+
+int
+bar (_Bool x)
+{
+ return x ? 98 : 97;
+}
Jakub
