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Re: [PATCH] Clear SSA_NAME_ANTI_RANGE_P when appropriate (PR tree-optimization/67821)
- From: Marek Polacek <polacek at redhat dot com>
- To: Richard Biener <rguenther at suse dot de>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 5 Oct 2015 16:25:44 +0200
- Subject: Re: [PATCH] Clear SSA_NAME_ANTI_RANGE_P when appropriate (PR tree-optimization/67821)
- Authentication-results: sourceware.org; auth=none
- References: <20151005135323 dot GK6184 at redhat dot com> <alpine dot LSU dot 2 dot 11 dot 1510051605430 dot 6516 at zhemvz dot fhfr dot qr>
On Mon, Oct 05, 2015 at 04:08:05PM +0200, Richard Biener wrote:
> On Mon, 5 Oct 2015, Marek Polacek wrote:
>
> > Here, we were crashing on an assert in duplicate_ssa_name_range_info:
> >
> > 506 gcc_assert (!SSA_NAME_ANTI_RANGE_P (name));
> >
> > The problem is that reset_flow_sensitive_info wasn't clearing the
> > SSA_NAME_ANTI_RANGE_P flag; I don't think NULL SSA_NAME_RANGE_INFO
> > can ever describe an anti-range...
>
> Yeah, also not a range. Thus I think the assert is bogus (aka
> superfluous) if !SSA_NAME_RANGE_INFO (name) holds.
Hm, true, and duplicate_ssa_name_range_info unconditionally sets
SSA_NAME_ANTI_RANGE_P...
> Otherwise other setters of SSA_NAME_RANGE_INFO would need to make
> sure SSA_NAME_ANTI_RANGE_P is cleared as well.
They mostly do, if I'm looking right, e.g.
tree-ssa-phiopt.c:1016
tree-ssa-loop-im.c:1224
tree-ssa-loop-im.c:1294
and I've also seen
<https://gcc.gnu.org/ml/gcc-patches/2015-01/msg00127.html>.
> So - can you instead remove the assert?
Sure. So is the following ok once it passes the usual testing?
2015-10-05 Marek Polacek <polacek@redhat.com>
PR tree-optimization/67821
* tree-ssanames.c (duplicate_ssa_name_range_info): Remove an assert.
* gcc.dg/torture/pr67821-2.c: New test.
* gcc.dg/torture/pr67821.c: New test.
diff --git gcc/testsuite/gcc.dg/torture/pr67821-2.c gcc/testsuite/gcc.dg/torture/pr67821-2.c
index e69de29..38cfc84 100644
--- gcc/testsuite/gcc.dg/torture/pr67821-2.c
+++ gcc/testsuite/gcc.dg/torture/pr67821-2.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+
+int a, b, c, d, e, g;
+short f;
+
+void
+fn1 ()
+{
+ int i;
+ f = a - b;
+ e = (c && (i = d = (unsigned) f - 1)) || i;
+ g = (unsigned) f - 1;
+ c && (d = 0);
+}
diff --git gcc/testsuite/gcc.dg/torture/pr67821.c gcc/testsuite/gcc.dg/torture/pr67821.c
index e69de29..1c9e8b9 100644
--- gcc/testsuite/gcc.dg/torture/pr67821.c
+++ gcc/testsuite/gcc.dg/torture/pr67821.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+
+int isdigit (int);
+
+int
+foo (const char *s)
+{
+ int success = 1;
+ const char *p = s + 2;
+ if (!isdigit (*p))
+ success = 0;
+ while (isdigit (*p))
+ ++p;
+ return success;
+}
diff --git gcc/tree-ssanames.c gcc/tree-ssanames.c
index 64e2379..91f4ed8 100644
--- gcc/tree-ssanames.c
+++ gcc/tree-ssanames.c
@@ -503,7 +503,6 @@ duplicate_ssa_name_range_info (tree name, enum value_range_type range_type,
gcc_assert (!POINTER_TYPE_P (TREE_TYPE (name)));
gcc_assert (!SSA_NAME_RANGE_INFO (name));
- gcc_assert (!SSA_NAME_ANTI_RANGE_P (name));
if (!range_info)
return;
Marek