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re PR rtl-optimization/68217 (Wrong constant folding) 

gcc/ChangeLog:

2016-07-29  Kugan Vivekanandarajah  <kuganv@linaro.org>

	PR middle-end/68217
	* tree-vrp.c (extract_range_from_binary_expr_1): In case of signed
	& sign-bit-CST, generate [-INF, 0] instead of [-INF, INF].


gcc/testsuite/ChangeLog:

2016-07-29  Kugan Vivekanandarajah  <kuganv@linaro.org>

	PR middle-end/68217
	* gcc.dg/pr68217.c: New test.

From-SVN: r238846
This commit is contained in:
Kugan Vivekanandarajah 2016-07-29 00:35:23 +00:00 committed by Kugan Vivekanandarajah
parent 257490974f
commit 883b6d4e1b
4 changed files with 43 additions and 0 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2016-07-29 Kugan Vivekanandarajah <kuganv@linaro.org>
PR middle-end/68217
* tree-vrp.c (extract_range_from_binary_expr_1): In case of signed
& sign-bit-CST, generate [-INF, 0] instead of [-INF, INF].
2016-07-28 Michael Meissner <meissner@linux.vnet.ibm.com>
* config/rs6000/rs6000-protos.h (rs6000_split_vec_extract_var):

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2016-07-29 Kugan Vivekanandarajah <kuganv@linaro.org>
PR middle-end/68217
* gcc.dg/pr68217.c: New test.
2016-07-28 Steven G. Kargl <kargl@gcc.gnu.org>
PR fortran/71067

14
gcc/testsuite/gcc.dg/pr68217.c Normal file
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@ -0,0 +1,14 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-vrp1" } */
int foo (void)
{
volatile int a = -1;
long long b = (1LL << (sizeof (b) * 8 - 1)); // LLONG_MIN
long long x = (a & b); // x == 0x8000000000000000
if (x < 1LL) { ; } else { __builtin_abort(); }
return 0;
}
/* { dg-final { scan-tree-dump "\\\[-INF, 0\\\]" "vrp1" } } */

18
gcc/tree-vrp.c
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@ -3067,6 +3067,24 @@ extract_range_from_binary_expr_1 (value_range *vr,
if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0)
wmax = wi::min (wmax, vr1.max, TYPE_SIGN (expr_type));
max = wide_int_to_tree (expr_type, wmax);
cmp = compare_values (min, max);
/* PR68217: In case of signed & sign-bit-CST should
result in [-INF, 0] instead of [-INF, INF]. */
if (cmp == -2 || cmp == 1)
{
wide_int sign_bit
= wi::set_bit_in_zero (TYPE_PRECISION (expr_type) - 1,
TYPE_PRECISION (expr_type));
if (!TYPE_UNSIGNED (expr_type)
&& ((value_range_constant_singleton (&vr0)
&& !wi::cmps (vr0.min, sign_bit))
|| (value_range_constant_singleton (&vr1)
&& !wi::cmps (vr1.min, sign_bit))))
{
min = TYPE_MIN_VALUE (expr_type);
max = build_int_cst (expr_type, 0);
}
}
}
else if (code == BIT_IOR_EXPR)
{