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[Bug tree-optimization/53986] missing vrp on bit-mask test, LSHIFT_EXPR not handled
- From: "vries at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Sun, 05 Aug 2012 13:32:15 +0000
- Subject: [Bug tree-optimization/53986] missing vrp on bit-mask test, LSHIFT_EXPR not handled
- Auto-submitted: auto-generated
- References: <bug-53986-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53986
--- Comment #6 from vries at gcc dot gnu.org 2012-08-05 13:32:15 UTC ---
> s_1 (u)s_1 s_1+16 ((u)s_1)+16 T T
> -16 4294967280 0 0 0 0
> -12 4294967284 4 4 0 0
> -9 4294967287 7 7 0 0
> -17 4294967279 -1 4294967295 0 1
> $
I think you forgot the cast to unsigned after the add that represents the
currently generated code:
...
@@ -13,7 +13,7 @@
unsigned int uv = (unsigned) v;
printf ("%-12d%-12u%-12d%-12u\t%2d%2d\n",
v, uv, v+16, uv+16,
- (v+16) > 7, (uv+16) > 7);
+ (unsigned int)(v+16) > 7, (uv+16) > 7);
}
return 0;
}
...
With that added I see:
...
s_1 (u)s_1 s_1+16 ((u)s_1)+16 T T
-16 4294967280 0 0 0 0
-12 4294967284 4 4 0 0
-9 4294967287 7 7 0 0
-17 4294967279 -1 4294967295 1 1
...
We now see the correct result for all 4 cases for both methods.