From 891bdbf2b0432b4aa3d3e76923617fcb4fd33cf6 Mon Sep 17 00:00:00 2001
From: Andrew MacLeod <amacleod@redhat.com>
Date: Tue, 17 Aug 2021 10:50:56 +0200
Subject: [PATCH] Special case -TYPE_MIN_VALUE for flag_wrapv in
operator_abs::op1_range.
With flag_wrapv, -TYPE_MIN_VALUE = TYPE_MIN_VALUE which is
unrepresentable. We currently special case this in the ABS folding
routine, but are missing similar treatment in operator_abs::op1_range.
Tested on x86-64 Linux.
PR tree-optimization/101938
gcc/ChangeLog:
* range-op.cc (operator_abs::op1_range): Special case
-TYPE_MIN_VALUE for flag_wrapv.
gcc/testsuite/ChangeLog:
* gcc.dg/pr101938.c: New test.
---
gcc/range-op.cc | 6 ++++++
gcc/testsuite/gcc.dg/pr101938.c | 28 ++++++++++++++++++++++++++++
2 files changed, 34 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/pr101938.c
diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index eb66e12677fe..56eccf471a20 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -3642,6 +3642,12 @@ operator_abs::op1_range (irange &r, tree type,
r.union_ (int_range<1> (type,
-positives.upper_bound (i),
-positives.lower_bound (i)));
+ // With flag_wrapv, -TYPE_MIN_VALUE = TYPE_MIN_VALUE which is
+ // unrepresentable. Add -TYPE_MIN_VALUE in this case.
+ wide_int min_value = wi::min_value (TYPE_PRECISION (type), TYPE_SIGN (type));
+ wide_int lb = lhs.lower_bound ();
+ if (!TYPE_OVERFLOW_UNDEFINED (type) && wi::eq_p (lb, min_value))
+ r.union_ (int_range<2> (type, lb, lb));
return true;
}
diff --git a/gcc/testsuite/gcc.dg/pr101938.c b/gcc/testsuite/gcc.dg/pr101938.c
new file mode 100644
index 000000000000..82777554eaf7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr101938.c
@@ -0,0 +1,28 @@
+// { dg-do run }
+// { dg-require-effective-target lp64 }
+// { dg-options "-O2 -fwrapv" }
+
+typedef long long int int64;
+#define INT64CONST(x) (x##LL)
+/* -9223372036854775808ULL */
+#define INT64_MIN (-INT64CONST(0x7FFFFFFFFFFFFFFF) - 1)
+
+static void __attribute__((noipa)) foo(int64 arg1, int64 arg2) {
+ int64 a1 = -arg1;
+ int64 a2 = (arg2 < 0) ? arg2 : -arg2;
+
+ if (a1 > a2) {
+ int64 swap = arg1;
+ arg1 = arg2;
+ arg2 = swap;
+ }
+
+ if (arg1 == INT64_MIN && arg2 == -1) return;
+
+ __builtin_abort();
+}
+
+int main() {
+ foo(-1, INT64_MIN);
+ return 0;
+}
--
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