aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorAldy Hernandez <aldyh@redhat.com>2022-11-06 13:05:39 +0100
committerAldy Hernandez <aldyh@redhat.com>2022-11-08 15:17:14 +0100
commitb74dd1bbd2a02a0755bc882c6e64964b2a47ba5d (patch)
treee370ae531c043421fde6d528f95e6a99d3e0c5dd
parent7ca912b46e0eb45ebefeb0eda4c28afe1513d272 (diff)
downloadgcc-b74dd1bbd2a02a0755bc882c6e64964b2a47ba5d.zip
gcc-b74dd1bbd2a02a0755bc882c6e64964b2a47ba5d.tar.gz
gcc-b74dd1bbd2a02a0755bc882c6e64964b2a47ba5d.tar.bz2
Use bit-CCP in range-ops.
After Jakub and Richi's suggestion of using the same representation for tracking known bits as we do in CCP, I took a peek at the code and realized there's a plethora of bit-tracking code there that we could be sharing with range-ops. For example, the multiplication optimizations are way better than what I had cobbled together. For that matter, our maybe nonzero tracking as a whole has a lot of room for improvement. Being the lazy ass that I am, I think we should just use one code base (CCP's). This patch provides a thin wrapper for converting the irange maybe nonzero bits to what CCP requires, and uses that to call into bit_value_binop(). I have so far converted the MULT_EXPR range-op entry to use it, as the DIV_EXPR entry we have gets a case CCP doesn't get so I'd like to contribute the enhancement to CCP before converting over. I'd like to use this approach with the dozen or so tree_code's that are handled in CCP, thus saving us from having to implement any of them :). Early next season I'd like to change irange's internal representation to a pair of value / mask, and start tracking all known bits. This ties in nicely with our plan for tracking known set bits. Perhaps if the stars align, we could merge the bit twiddling in CCP into range-ops and have a central repository for it. That is, once we make the switch to wide-ints, and assuming there are no performance issues. Note that range-ops is our lowest level abstraction. i.e. it's just the math, there's no GORI or ranger, or even the concept of a symbolic or SSA. gcc/ChangeLog: * range-op.cc (irange_to_masked_value): New. (update_known_bitmask): New. (operator_mult::fold_range): Call update_known_bitmask.
-rw-r--r--gcc/range-op.cc64
1 files changed, 49 insertions, 15 deletions
diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index a13e888..846931d 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -46,6 +46,54 @@ along with GCC; see the file COPYING3. If not see
#include "wide-int.h"
#include "value-relation.h"
#include "range-op.h"
+#include "tree-ssa-ccp.h"
+
+// Convert irange bitmasks into a VALUE MASK pair suitable for calling CCP.
+
+static void
+irange_to_masked_value (const irange &r, widest_int &value, widest_int &mask)
+{
+ if (r.singleton_p ())
+ {
+ mask = 0;
+ value = widest_int::from (r.lower_bound (), TYPE_SIGN (r.type ()));
+ }
+ else
+ {
+ mask = widest_int::from (r.get_nonzero_bits (), TYPE_SIGN (r.type ()));
+ value = 0;
+ }
+}
+
+// Update the known bitmasks in R when applying the operation CODE to
+// LH and RH.
+
+static void
+update_known_bitmask (irange &r, tree_code code,
+ const irange &lh, const irange &rh)
+{
+ if (r.undefined_p () || lh.undefined_p () || rh.undefined_p ())
+ return;
+
+ widest_int value, mask, lh_mask, rh_mask, lh_value, rh_value;
+ tree type = r.type ();
+ signop sign = TYPE_SIGN (type);
+ int prec = TYPE_PRECISION (type);
+ signop lh_sign = TYPE_SIGN (lh.type ());
+ signop rh_sign = TYPE_SIGN (rh.type ());
+ int lh_prec = TYPE_PRECISION (lh.type ());
+ int rh_prec = TYPE_PRECISION (rh.type ());
+
+ irange_to_masked_value (lh, lh_value, lh_mask);
+ irange_to_masked_value (rh, rh_value, rh_mask);
+ bit_value_binop (code, sign, prec, &value, &mask,
+ lh_sign, lh_prec, lh_value, lh_mask,
+ rh_sign, rh_prec, rh_value, rh_mask);
+
+ int_range<2> tmp (type);
+ tmp.set_nonzero_bits (value | mask);
+ r.intersect (tmp);
+}
// Return the upper limit for a type.
@@ -1775,21 +1823,7 @@ operator_mult::fold_range (irange &r, tree type,
if (!cross_product_operator::fold_range (r, type, lh, rh, trio))
return false;
- if (lh.undefined_p ())
- return true;
-
- tree t;
- if (rh.singleton_p (&t))
- {
- wide_int w = wi::to_wide (t);
- int shift = wi::exact_log2 (w);
- if (shift != -1)
- {
- wide_int nz = lh.get_nonzero_bits ();
- nz = wi::lshift (nz, shift);
- r.set_nonzero_bits (nz);
- }
- }
+ update_known_bitmask (r, MULT_EXPR, lh, rh);
return true;
}