On April 18, 2017 5:06:48 PM GMT+02:00, Jakub Jelinek <ja...@redhat.com> wrote:
>Hi!
>
>As can be seen on the testcase, intersect_ranges in some cases attempts
>to add or subtract 1 from one of the bounds. That is fine except for
>1-bit signed type, where 1 is not a value in the range of the type,
>so already build_int_cst yields (OVF) constant.
>
>The following patch fixes it by special casing those, instead of
>adding/subtracting 1 for those types it subtracts/adds -1.
>
>Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ick.
OK.
Richard.
>2017-04-18 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/80443
> * tree-vrp.c (intersect_ranges): For signed 1-bit precision type,
> instead of adding 1, subtract -1 and similarly instead of subtracting
> 1 add -1.
>
> * gcc.c-torture/compile/pr80443.c: New test.
>
>--- gcc/tree-vrp.c.jj 2017-03-23 15:49:55.000000000 +0100
>+++ gcc/tree-vrp.c 2017-04-18 10:09:44.560549718 +0200
>@@ -8756,20 +8756,32 @@ intersect_ranges (enum value_range_type
> /* Choose the right gap if the left one is empty. */
> if (mineq)
> {
>- if (TREE_CODE (vr1max) == INTEGER_CST)
>- *vr0min = int_const_binop (PLUS_EXPR, vr1max,
>- build_int_cst (TREE_TYPE (vr1max),
>1));
>- else
>+ if (TREE_CODE (vr1max) != INTEGER_CST)
> *vr0min = vr1max;
>+ else if (TYPE_PRECISION (TREE_TYPE (vr1max)) == 1
>+ && !TYPE_UNSIGNED (TREE_TYPE (vr1max)))
>+ *vr0min
>+ = int_const_binop (MINUS_EXPR, vr1max,
>+ build_int_cst (TREE_TYPE (vr1max), -1));
>+ else
>+ *vr0min
>+ = int_const_binop (PLUS_EXPR, vr1max,
>+ build_int_cst (TREE_TYPE (vr1max), 1));
> }
> /* Choose the left gap if the right one is empty. */
> else if (maxeq)
> {
>- if (TREE_CODE (vr1min) == INTEGER_CST)
>- *vr0max = int_const_binop (MINUS_EXPR, vr1min,
>- build_int_cst (TREE_TYPE (vr1min),
>1));
>- else
>+ if (TREE_CODE (vr1min) != INTEGER_CST)
> *vr0max = vr1min;
>+ else if (TYPE_PRECISION (TREE_TYPE (vr1min)) == 1
>+ && !TYPE_UNSIGNED (TREE_TYPE (vr1min)))
>+ *vr0max
>+ = int_const_binop (PLUS_EXPR, vr1min,
>+ build_int_cst (TREE_TYPE (vr1min), -1));
>+ else
>+ *vr0max
>+ = int_const_binop (MINUS_EXPR, vr1min,
>+ build_int_cst (TREE_TYPE (vr1min), 1));
> }
> /* Choose the anti-range if the range is effectively varying. */
> else if (vrp_val_is_min (*vr0min)
>@@ -8811,22 +8823,34 @@ intersect_ranges (enum value_range_type
> if (mineq)
> {
> *vr0type = VR_RANGE;
>- if (TREE_CODE (*vr0max) == INTEGER_CST)
>- *vr0min = int_const_binop (PLUS_EXPR, *vr0max,
>- build_int_cst (TREE_TYPE (*vr0max),
>1));
>- else
>+ if (TREE_CODE (*vr0max) != INTEGER_CST)
> *vr0min = *vr0max;
>+ else if (TYPE_PRECISION (TREE_TYPE (*vr0max)) == 1
>+ && !TYPE_UNSIGNED (TREE_TYPE (*vr0max)))
>+ *vr0min
>+ = int_const_binop (MINUS_EXPR, *vr0max,
>+ build_int_cst (TREE_TYPE (*vr0max), -1));
>+ else
>+ *vr0min
>+ = int_const_binop (PLUS_EXPR, *vr0max,
>+ build_int_cst (TREE_TYPE (*vr0max), 1));
> *vr0max = vr1max;
> }
> /* Choose the left gap if the right is empty. */
> else if (maxeq)
> {
> *vr0type = VR_RANGE;
>- if (TREE_CODE (*vr0min) == INTEGER_CST)
>- *vr0max = int_const_binop (MINUS_EXPR, *vr0min,
>- build_int_cst (TREE_TYPE (*vr0min),
>1));
>- else
>+ if (TREE_CODE (*vr0min) != INTEGER_CST)
> *vr0max = *vr0min;
>+ else if (TYPE_PRECISION (TREE_TYPE (*vr0min)) == 1
>+ && !TYPE_UNSIGNED (TREE_TYPE (*vr0min)))
>+ *vr0max
>+ = int_const_binop (PLUS_EXPR, *vr0min,
>+ build_int_cst (TREE_TYPE (*vr0min), -1));
>+ else
>+ *vr0max
>+ = int_const_binop (MINUS_EXPR, *vr0min,
>+ build_int_cst (TREE_TYPE (*vr0min), 1));
> *vr0min = vr1min;
> }
> /* Choose the anti-range if the range is effectively varying. */
>--- gcc/testsuite/gcc.c-torture/compile/pr80443.c.jj 2017-04-18
>10:16:35.867952863 +0200
>+++ gcc/testsuite/gcc.c-torture/compile/pr80443.c 2017-04-18
>10:16:21.000000000 +0200
>@@ -0,0 +1,20 @@
>+/* PR tree-optimization/80443 */
>+
>+struct S { int a : 1; } b, c;
>+signed char d, e, f;
>+
>+void
>+foo ()
>+{
>+ while (f)
>+ {
>+ signed char g = b.a;
>+ if (g)
>+ b.a = ~(1 + (d || c.a));
>+ if (b.a < g && b.a)
>+ g = 0;
>+ if (b.a > c.a)
>+ b.a = g;
>+ c.a = e;
>+ }
>+}
>
> Jakub
