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[range-ops] patch 05/04: bonus round!
- From: Aldy Hernandez <aldyh at redhat dot com>
- To: Richard Biener <richard dot guenther at gmail dot com>
- Cc: gcc-patches <gcc-patches at gcc dot gnu dot org>, Andrew MacLeod <amacleod at redhat dot com>
- Date: Mon, 1 Jul 2019 06:24:52 -0400
- Subject: [range-ops] patch 05/04: bonus round!
This is completely unrelated to range-ops itself, but may yield better
results in value_range intersections. It's just something I found while
working on VRP, and have been dragging around on our branch.
If we know the intersection of two ranges is the empty set, there is no
need to conservatively add anything to the result.
Tested on x86-64 Linux with --enable-languages=all.
Aldy
commit 4f9aa7bd1066267eee92f622ff29d78534158e20
Author: Aldy Hernandez <aldyh@redhat.com>
Date: Fri Jun 28 11:34:19 2019 +0200
Do not try to further refine a VR_UNDEFINED result when intersecting
value_ranges.
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 01fb97cedb2..b0d78ee6871 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2019-07-01 Aldy Hernandez <aldyh@redhat.com>
+
+ * tree-vrp.c (intersect_ranges): If we know the intersection is
+ empty, there is no need to conservatively add anything else to
+ the set.
+
2019-06-26 Jeff Law <law@redhat.com>
PR tree-optimization/90883
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index dc7f825efc8..594ee9adc17 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -5977,6 +5977,11 @@ intersect_ranges (enum value_range_kind *vr0type,
gcc_unreachable ();
}
+ /* If we know the intersection is empty, there's no need to
+ conservatively add anything else to the set. */
+ if (*vr0type == VR_UNDEFINED)
+ return;
+
/* 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