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* [gcc r11-6374] reassoc: Optimize x > 0x1fff || y > 0x1fff into (x | y) > 0x1fff [PR56719]
@ 2020-12-31 9:19 Jakub Jelinek
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From: Jakub Jelinek @ 2020-12-31 9:19 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:d96b8556e569a1ccce36ef990e167031d07a661a
commit r11-6374-gd96b8556e569a1ccce36ef990e167031d07a661a
Author: Jakub Jelinek <jakub@redhat.com>
Date: Thu Dec 31 10:19:06 2020 +0100
reassoc: Optimize x > 0x1fff || y > 0x1fff into (x | y) > 0x1fff [PR56719]
The following patch adds an optimization mentioned in PR56719 #c8.
We already have the x != 0 && y != 0 && z != 0 into (x | y | z) != 0
and x != -1 && y != -1 && y != -1 into (x & y & z) != -1
optimizations, this patch just extends that to
x < C && y < C && z < C for power of two constants C into
(x | y | z) < C (for unsigned comparisons).
I didn't want to create too many buckets (there can be TYPE_PRECISION such
constants), so the patch instead just uses one buckets for all such
constants and loops over that bucket up to TYPE_PRECISION times.
2020-12-31 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/56719
* tree-ssa-reassoc.c (optimize_range_tests_cmp_bitwise): Also optimize
x < C && y < C && z < C when C is a power of two constant into
(x | y | z) < C.
* gcc.dg/tree-ssa/pr56719.c: New test.
Diff:
---
gcc/testsuite/gcc.dg/tree-ssa/pr56719.c | 33 +++++++++++++
gcc/tree-ssa-reassoc.c | 87 +++++++++++++++++++++++++++++----
2 files changed, 110 insertions(+), 10 deletions(-)
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr56719.c b/gcc/testsuite/gcc.dg/tree-ssa/pr56719.c
new file mode 100644
index 00000000000..5030b695417
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr56719.c
@@ -0,0 +1,33 @@
+/* PR tree-optimization/56719 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump-times " > 1023;" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " > 2047;" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " > 8191;" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " <= 1023;" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " <= 4095;" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " <= 8191;" 1 "optimized" } } */
+
+int
+f1 (int x, int y)
+{
+ return x > 0x3ffU || y > 0x3ffU;
+}
+
+int
+f2 (int x, int y, int z, unsigned w)
+{
+ return x > 0x1fffU || z > 0x7ffU || w > 0x7ffU || y > 0x1fffU;
+}
+
+int
+f3 (int x, int y)
+{
+ return x <= 0x3ffU && y <= 0x3ffU;
+}
+
+int
+f4 (int x, int y, unsigned z, unsigned w)
+{
+ return x <= 0x1fffU && z <= 0xfff && w <= 0xfff && y <= 0x1fffU;
+}
diff --git a/gcc/tree-ssa-reassoc.c b/gcc/tree-ssa-reassoc.c
index e594230436d..4bc9004ded7 100644
--- a/gcc/tree-ssa-reassoc.c
+++ b/gcc/tree-ssa-reassoc.c
@@ -3317,7 +3317,9 @@ optimize_range_tests_to_bit_test (enum tree_code opcode, int first, int length,
}
/* Optimize x != 0 && y != 0 && z != 0 into (x | y | z) != 0
- and similarly x != -1 && y != -1 && y != -1 into (x & y & z) != -1. */
+ and similarly x != -1 && y != -1 && y != -1 into (x & y & z) != -1.
+ Also, handle x < C && y < C && z < C where C is power of two as
+ (x | y | z) < C. */
static bool
optimize_range_tests_cmp_bitwise (enum tree_code opcode, int first, int length,
@@ -3333,20 +3335,44 @@ optimize_range_tests_cmp_bitwise (enum tree_code opcode, int first, int length,
for (i = first; i < length; i++)
{
+ int idx;
+
if (ranges[i].exp == NULL_TREE
|| TREE_CODE (ranges[i].exp) != SSA_NAME
|| !ranges[i].in_p
|| TYPE_PRECISION (TREE_TYPE (ranges[i].exp)) <= 1
- || TREE_CODE (TREE_TYPE (ranges[i].exp)) == BOOLEAN_TYPE
- || ranges[i].low == NULL_TREE
- || ranges[i].low != ranges[i].high)
+ || TREE_CODE (TREE_TYPE (ranges[i].exp)) == BOOLEAN_TYPE)
continue;
- bool zero_p = integer_zerop (ranges[i].low);
- if (!zero_p && !integer_all_onesp (ranges[i].low))
+ if (ranges[i].low != NULL_TREE
+ && ranges[i].high != NULL_TREE
+ && tree_int_cst_equal (ranges[i].low, ranges[i].high))
+ {
+ idx = !integer_zerop (ranges[i].low);
+ if (idx && !integer_all_onesp (ranges[i].low))
+ continue;
+ }
+ else if (ranges[i].high != NULL_TREE
+ && TREE_CODE (ranges[i].high) == INTEGER_CST)
+ {
+ wide_int w = wi::to_wide (ranges[i].high);
+ int prec = TYPE_PRECISION (TREE_TYPE (ranges[i].exp));
+ int l = wi::clz (w);
+ idx = 2;
+ if (l <= 0
+ || l >= prec
+ || w != wi::mask (prec - l, false, prec))
+ continue;
+ if (!((TYPE_UNSIGNED (TREE_TYPE (ranges[i].exp))
+ && ranges[i].low == NULL_TREE)
+ || (ranges[i].low
+ && integer_zerop (ranges[i].low))))
+ continue;
+ }
+ else
continue;
- b = TYPE_PRECISION (TREE_TYPE (ranges[i].exp)) * 2 + !zero_p;
+ b = TYPE_PRECISION (TREE_TYPE (ranges[i].exp)) * 3 + idx;
if (buckets.length () <= b)
buckets.safe_grow_cleared (b + 1, true);
if (chains.length () <= (unsigned) i)
@@ -3359,6 +3385,44 @@ optimize_range_tests_cmp_bitwise (enum tree_code opcode, int first, int length,
if (i && chains[i - 1])
{
int j, k = i;
+ if ((b % 3) == 2)
+ {
+ /* When ranges[X - 1].high + 1 is a power of two,
+ we need to process the same bucket up to
+ precision - 1 times, each time split the entries
+ with the same high bound into one chain and the
+ rest into another one to be processed later. */
+ int this_prev = i;
+ int other_prev = 0;
+ for (j = chains[i - 1]; j; j = chains[j - 1])
+ {
+ if (tree_int_cst_equal (ranges[i - 1].high,
+ ranges[j - 1].high))
+ {
+ chains[this_prev - 1] = j;
+ this_prev = j;
+ }
+ else if (other_prev == 0)
+ {
+ buckets[b] = j;
+ other_prev = j;
+ }
+ else
+ {
+ chains[other_prev - 1] = j;
+ other_prev = j;
+ }
+ }
+ chains[this_prev - 1] = 0;
+ if (other_prev)
+ chains[other_prev - 1] = 0;
+ if (chains[i - 1] == 0)
+ {
+ if (other_prev)
+ b--;
+ continue;
+ }
+ }
for (j = chains[i - 1]; j; j = chains[j - 1])
{
gimple *gk = SSA_NAME_DEF_STMT (ranges[k - 1].exp);
@@ -3426,8 +3490,8 @@ optimize_range_tests_cmp_bitwise (enum tree_code opcode, int first, int length,
exp = gimple_assign_lhs (g);
}
g = gimple_build_assign (make_ssa_name (id >= l ? type1 : type2),
- (b & 1) ? BIT_AND_EXPR : BIT_IOR_EXPR,
- op, exp);
+ (b % 3) == 1
+ ? BIT_AND_EXPR : BIT_IOR_EXPR, op, exp);
gimple_seq_add_stmt_without_update (&seq, g);
op = gimple_assign_lhs (g);
}
@@ -3435,10 +3499,13 @@ optimize_range_tests_cmp_bitwise (enum tree_code opcode, int first, int length,
if (update_range_test (&ranges[k - 1], NULL, candidates.address (),
candidates.length (), opcode, ops, op,
seq, true, ranges[k - 1].low,
- ranges[k - 1].low, strict_overflow_p))
+ ranges[k - 1].high, strict_overflow_p))
any_changes = true;
else
gimple_seq_discard (seq);
+ if ((b % 3) == 2 && buckets[b] != i)
+ /* There is more work to do for this bucket. */
+ b--;
}
return any_changes;
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