Hi,
In vrp intersect_ranges, Richard recently changed it to create integer
value ranges when it is integer singleton.
Maybe we should do the same when the other range is a complex ranges
with SSA_NAME (like [x+2, +INF])?
Attached patch tries to do this. There are cases where it will be
beneficial as the testcase in the patch. (For this testcase to work
with Early VRP, we need the patch posted at
https://gcc.gnu.org/ml/gcc-patches/2016-10/msg00413.html)
Bootstrapped and regression tested on x86_64-linux-gnu with no new
regressions.
Thanks,
Kugan
gcc/testsuite/ChangeLog:
2016-10-07 Kugan Vivekanandarajah <kug...@linaro.org>
* gcc.dg/tree-ssa/evrp6.c: New test.
gcc/ChangeLog:
2016-10-07 Kugan Vivekanandarajah <kug...@linaro.org>
* tree-vrp.c (intersect_ranges): If we failed to handle
the intersection and the other range involves computation with
symbolic values, choose integer range if available.
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/evrp6.c
b/gcc/testsuite/gcc.dg/tree-ssa/evrp6.c
index e69de29..3740da0 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/evrp6.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/evrp6.c
@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-evrp" } */
+
+extern void abort (void);
+
+int
+foo (int k, int j)
+{
+ if (j >= 10)
+ {
+ if (j < k)
+ {
+ k++;
+ if (k < 10)
+ abort ();
+ }
+ }
+
+ return j;
+}
+/* { dg-final { scan-tree-dump "\\\[12, \\+INF" "evrp" } } */
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 7a08be7..2706854 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -8553,11 +8553,26 @@ intersect_ranges (enum value_range_type *vr0type,
gcc_unreachable ();
}
+ /* If one is a complex value range involving SSA_NAME
+ and other is INTEGER_CST, prefer INTEGER_CST. */
+ else if (vr1type == VR_RANGE
+ && INTEGER_CST == TREE_CODE (vr1min)
+ && INTEGER_CST == TREE_CODE (vr1max)
+ && (((INTEGER_CST != TREE_CODE (*vr0min)
+ && SSA_NAME != TREE_CODE (*vr0min))
+ || ((INTEGER_CST != TREE_CODE (*vr0max)
+ && SSA_NAME != TREE_CODE (*vr0max))))))
+ {
+ *vr0type = vr1type;
+ *vr0min = vr1min;
+ *vr0max = vr1max;
+ }
+
/* As a fallback simply use { *VRTYPE, *VR0MIN, *VR0MAX } as
result for the intersection. That's always a conservative
correct estimate unless VR1 is a constant singleton range
in which case we choose that. */
- if (vr1type == VR_RANGE
+ else if (vr1type == VR_RANGE
&& is_gimple_min_invariant (vr1min)
&& vrp_operand_equal_p (vr1min, vr1max))
{
