re PR middle-end/91450 (__builtin_mul_overflow(A,B,R) wrong code if product < 0,...

	PR middle-end/91450
	* internal-fn.c (expand_mul_overflow): For s1 * s2 -> ur, if one
	operand is negative and one non-negative, compare the non-negative
	one against 0 rather than comparing s1 & s2 against 0.  Otherwise,
	don't compare (s1 & s2) == 0, but compare separately both s1 == 0
	and s2 == 0, unless one of them is known to be negative.  Remove
	tem2 variable, use tem where tem2 has been used before.

	* gcc.c-torture/execute/pr91450-1.c: New test.
	* gcc.c-torture/execute/pr91450-2.c: New test.

From-SVN: r278437

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 030d71be314df991721b39973faa5f75820502e9..6560a39c7055510c1bfd6f54908bd5b01a31b451 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2019-11-19  Jakub Jelinek  <jakub@redhat.com>
+
+       PR middle-end/91450
+       * internal-fn.c (expand_mul_overflow): For s1 * s2 -> ur, if one
+       operand is negative and one non-negative, compare the non-negative
+       one against 0 rather than comparing s1 & s2 against 0.  Otherwise,
+       don't compare (s1 & s2) == 0, but compare separately both s1 == 0
+       and s2 == 0, unless one of them is known to be negative.  Remove
+       tem2 variable, use tem where tem2 has been used before.
+
 2019-11-19  Eric Botcazou  <ebotcazou@adacore.com>
 
        * doc/invoke.texi (-gno-internal-reset-location-views): Fix typo.

diff --git a/gcc/internal-fn.c b/gcc/internal-fn.c
index 88d52d2c25da8f37d5965c5efca9cf57ecf2f228..6bbbc9e946e72a83c6defa38750cbf2b4ff3d4ac 100644 (file)
--- a/gcc/internal-fn.c
+++ b/gcc/internal-fn.c
@@ -1409,7 +1409,7 @@ expand_mul_overflow (location_t loc, tree lhs, tree arg0, tree arg1,
   /* s1 * s2 -> ur  */
   if (!uns0_p && !uns1_p && unsr_p)
     {
-      rtx tem, tem2;
+      rtx tem;
       switch (pos_neg0 | pos_neg1)
        {
        case 1: /* Both operands known to be non-negative.  */
@@ -1439,10 +1439,8 @@ expand_mul_overflow (location_t loc, tree lhs, tree arg0, tree arg1,
              ops.op2 = NULL_TREE;
              ops.location = loc;
              res = expand_expr_real_2 (&ops, NULL_RTX, mode, EXPAND_NORMAL);
-             tem = expand_binop (mode, and_optab, op0, op1, NULL_RTX, false,
-                                 OPTAB_LIB_WIDEN);
-             do_compare_rtx_and_jump (tem, const0_rtx, EQ, true, mode,
-                                      NULL_RTX, NULL, done_label,
+             do_compare_rtx_and_jump (pos_neg0 == 1 ? op0 : op1, const0_rtx, EQ,
+                                      true, mode, NULL_RTX, NULL, done_label,
                                       profile_probability::very_likely ());
              goto do_error_label;
            }
@@ -1473,16 +1471,23 @@ expand_mul_overflow (location_t loc, tree lhs, tree arg0, tree arg1,
          arg1 = error_mark_node;
          emit_jump (do_main_label);
          emit_label (after_negate_label);
-         tem2 = expand_binop (mode, xor_optab, op0, op1, NULL_RTX, false,
-                              OPTAB_LIB_WIDEN);
-         do_compare_rtx_and_jump (tem2, const0_rtx, GE, false, mode, NULL_RTX,
-                                  NULL, do_main_label, profile_probability::very_likely ());
+         tem = expand_binop (mode, xor_optab, op0, op1, NULL_RTX, false,
+                             OPTAB_LIB_WIDEN);
+         do_compare_rtx_and_jump (tem, const0_rtx, GE, false, mode, NULL_RTX,
+                                  NULL, do_main_label,
+                                  profile_probability::very_likely ());
          /* One argument is negative here, the other positive.  This
             overflows always, unless one of the arguments is 0.  But
             if e.g. s2 is 0, (U) s1 * 0 doesn't overflow, whatever s1
             is, thus we can keep do_main code oring in overflow as is.  */
-         do_compare_rtx_and_jump (tem, const0_rtx, EQ, true, mode, NULL_RTX,
-                                  NULL, do_main_label, profile_probability::very_likely ());
+         if (pos_neg0 != 2)
+           do_compare_rtx_and_jump (op0, const0_rtx, EQ, true, mode, NULL_RTX,
+                                    NULL, do_main_label,
+                                    profile_probability::very_unlikely ());
+         if (pos_neg1 != 2)
+           do_compare_rtx_and_jump (op1, const0_rtx, EQ, true, mode, NULL_RTX,
+                                    NULL, do_main_label,
+                                    profile_probability::very_unlikely ());
          expand_arith_set_overflow (lhs, target);
          emit_label (do_main_label);
          goto do_main;

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index b569888344b4a90c7f21a25e1927971b0c3d8c35..16a410605eeec3162d745caaaa4414a25e50beab 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,9 @@
 2019-11-19  Jakub Jelinek  <jakub@redhat.com>
 
+       PR middle-end/91450
+       * gcc.c-torture/execute/pr91450-1.c: New test.
+       * gcc.c-torture/execute/pr91450-2.c: New test.
+
        PR c++/92504
        * g++.dg/gomp/pr92504.C: New test.
 

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr91450-1.c b/gcc/testsuite/gcc.c-torture/execute/pr91450-1.c
new file mode 100644 (file)
index 0000000..9aafc5f
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr91450-1.c
@@ -0,0 +1,88 @@
+/* PR middle-end/91450 */
+
+__attribute__((noipa)) unsigned long long
+foo (int a, int b)
+{
+  unsigned long long r;
+  if (!__builtin_mul_overflow (a, b, &r))
+    __builtin_abort ();
+  return r;
+}
+
+__attribute__((noipa)) unsigned long long
+bar (int a, int b)
+{
+  unsigned long long r;
+  if (a >= 0)
+    return 0;
+  if (!__builtin_mul_overflow (a, b, &r))
+    __builtin_abort ();
+  return r;
+}
+
+__attribute__((noipa)) unsigned long long
+baz (int a, int b)
+{
+  unsigned long long r;
+  if (b >= 0)
+    return 0;
+  if (!__builtin_mul_overflow (a, b, &r))
+    __builtin_abort ();
+  return r;
+}
+
+__attribute__((noipa)) unsigned long long
+qux (int a, int b)
+{
+  unsigned long long r;
+  if (a >= 0)
+    return 0;
+  if (b < 0)
+    return 0;
+  if (!__builtin_mul_overflow (a, b, &r))
+    __builtin_abort ();
+  return r;
+}
+
+__attribute__((noipa)) unsigned long long
+quux (int a, int b)
+{
+  unsigned long long r;
+  if (a < 0)
+    return 0;
+  if (b >= 0)
+    return 0;
+  if (!__builtin_mul_overflow (a, b, &r))
+    __builtin_abort ();
+  return r;
+}
+
+int
+main ()
+{
+  if (foo (-4, 2) != -8ULL)
+    __builtin_abort ();
+  if (foo (2, -4) != -8ULL)
+    __builtin_abort ();
+  if (bar (-4, 2) != -8ULL)
+    __builtin_abort ();
+  if (baz (2, -4) != -8ULL)
+    __builtin_abort ();
+  if (qux (-4, 2) != -8ULL)
+    __builtin_abort ();
+  if (quux (2, -4) != -8ULL)
+    __builtin_abort ();
+  if (foo (-2, 1) != -2ULL)
+    __builtin_abort ();
+  if (foo (1, -2) != -2ULL)
+    __builtin_abort ();
+  if (bar (-2, 1) != -2ULL)
+    __builtin_abort ();
+  if (baz (1, -2) != -2ULL)
+    __builtin_abort ();
+  if (qux (-2, 1) != -2ULL)
+    __builtin_abort ();
+  if (quux (1, -2) != -2ULL)
+    __builtin_abort ();
+  return 0;
+}

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr91450-2.c b/gcc/testsuite/gcc.c-torture/execute/pr91450-2.c
new file mode 100644 (file)
index 0000000..bfaabbb
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr91450-2.c
@@ -0,0 +1,76 @@
+/* PR middle-end/91450 */
+
+__attribute__((noipa)) void
+foo (int a, int b)
+{
+  unsigned long long r;
+  if (__builtin_mul_overflow (a, b, &r))
+    __builtin_abort ();
+  if (r != 0)
+    __builtin_abort ();
+}
+
+__attribute__((noipa)) void
+bar (int a, int b)
+{
+  unsigned long long r;
+  if (a >= 0)
+    return;
+  if (__builtin_mul_overflow (a, b, &r))
+    __builtin_abort ();
+  if (r != 0)
+    __builtin_abort ();
+}
+
+__attribute__((noipa)) void
+baz (int a, int b)
+{
+  unsigned long long r;
+  if (b >= 0)
+    return;
+  if (__builtin_mul_overflow (a, b, &r))
+    __builtin_abort ();
+  if (r != 0)
+    __builtin_abort ();
+}
+
+__attribute__((noipa)) void
+qux (int a, int b)
+{
+  unsigned long long r;
+  if (a >= 0)
+    return;
+  if (b < 0)
+    return;
+  if (__builtin_mul_overflow (a, b, &r))
+    __builtin_abort ();
+  if (r != 0)
+    __builtin_abort ();
+}
+
+__attribute__((noipa)) void
+quux (int a, int b)
+{
+  unsigned long long r;
+  if (a < 0)
+    return;
+  if (b >= 0)
+    return;
+  if (__builtin_mul_overflow (a, b, &r))
+    __builtin_abort ();
+  if (r != 0)
+    __builtin_abort ();
+}
+
+int
+main ()
+{
+  foo (-4, 0);
+  foo (0, -4);
+  foo (0, 0);
+  bar (-4, 0);
+  baz (0, -4);
+  qux (-4, 0);
+  quux (0, -4);
+  return 0;
+}