[gcc r14-8837] range-op: Fix up ABSU_EXPR handling [PR113756]

[gcc r14-8837] range-op: Fix up ABSU_EXPR handling [PR113756]

[Jakub Jelinek]

https://gcc.gnu.org/g:29998cc8a21b3a52f706275923166cd1f95d0555

commit r14-8837-g29998cc8a21b3a52f706275923166cd1f95d0555
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Feb 7 10:59:06 2024 +0100

    range-op: Fix up ABSU_EXPR handling [PR113756]
    
    ABSU_EXPR unary expr is special because it has a signed integer
    argument and unsigned integer result (of the same precision).
    
    The following testcase is miscompiled since ABSU_EXPR handling has
    been added to range-op because it uses widest_int::from with the
    result sign (i.e. UNSIGNED) rather than the operand sign (i.e. SIGNED),
    so e.g. for the 32-bit int argument mask ends up 0xffffffc1 or something
    similar and even when it has most significant bit in the precision set,
    in widest_int (tree-ssa-ccp.cc really should stop using widest_int, but
    that is I think stage1 task) it doesn't appear to be negative and so
    bit_value_unop ABSU_EXPR doesn't set the resulting mask/value from
    oring of the argument and its negation.
    
    Fixed thusly, not doing that for GIMPLE_BINARY_RHS because I don't know
    about a binary op that would need something similar.
    
    2024-02-06  Jakub Jelinek  <jakub@redhat.com>
    
            PR tree-optimization/113756
            * range-op.cc (update_known_bitmask): For GIMPLE_UNARY_RHS,
            use TYPE_SIGN (lh.type ()) instead of sign for widest_int::from
            of lh_bits value and mask.
    
            * gcc.dg/pr113756.c: New test.

Diff:
---
 gcc/range-op.cc                 |  6 ++++--
 gcc/testsuite/gcc.dg/pr113756.c | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index 9a1a3c8bcdbb..4ccb86ef0ba8 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -435,8 +435,10 @@ update_known_bitmask (irange &r, tree_code code,
       bit_value_unop (code, sign, prec, &widest_value, &widest_mask,
 		      TYPE_SIGN (lh.type ()),
 		      TYPE_PRECISION (lh.type ()),
-		      widest_int::from (lh_bits.value (), sign),
-		      widest_int::from (lh_bits.mask (), sign));
+		      widest_int::from (lh_bits.value (),
+					TYPE_SIGN (lh.type ())),
+		      widest_int::from (lh_bits.mask (),
+					TYPE_SIGN (lh.type ())));
       break;
     case GIMPLE_BINARY_RHS:
       bit_value_binop (code, sign, prec, &widest_value, &widest_mask,
diff --git a/gcc/testsuite/gcc.dg/pr113756.c b/gcc/testsuite/gcc.dg/pr113756.c
new file mode 100644
index 000000000000..14442206f8ab
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr113756.c
@@ -0,0 +1,36 @@
+/* PR tree-optimization/113756 */
+/* { dg-do run { target int32plus } } */
+/* { dg-options "-O2" } */
+
+int d, e, i, k, l = -8;
+signed char h, j;
+
+int
+bar (int n, int o, int p3)
+{
+  int a = o - p3, b = n - p3, c = a + b, f = -b, g = c < 0 ? -c : c;
+  return a <= f && a <= g ? o : p3;
+}
+
+void
+foo (int *n, unsigned short o)
+{
+  unsigned p = 8896;
+  for (; e >= 0; e--)
+    p = 5377;
+  for (; h <= 0; h++)
+    for (; j <= 0; j++)
+      {
+	*n = 1611581749;
+	i = bar (34, p - 5294, *n - 1611581687);
+	k = i + p + 65535 + o + *n - 1611718251;
+	if (k != 0)
+	  __builtin_abort ();
+      }
+}
+
+int
+main ()
+{
+  foo (&l, l);
+}