re PR middle-end/68046 (-ftrapv doesn't catch leaq-based overflows on x86-64)

2015-10-22  Richard Biener  <rguenther@suse.de>

	PR middle-end/68046
	PR middle-end/61893
	* optabs.c (emit_libcall_block_1): Allow a NULL_RTX equiv.
	(expand_binop): For -ftrapv optabs do not record an REG_EQUAL note.
	(expand_unop): Likewise.

	* gcc.dg/torture/ftrapv-2.c: New testcase.

From-SVN: r229170

gcc/ChangeLog

 2015-10-22  Richard Biener  <rguenther@suse.de>
 
+	PR middle-end/68046
+	PR middle-end/61893
+	* optabs.c (emit_libcall_block_1): Allow a NULL_RTX equiv.
+	(expand_binop): For -ftrapv optabs do not record an REG_EQUAL note.
+	(expand_unop): Likewise.
+
+2015-10-22  Richard Biener  <rguenther@suse.de>
+
 	* fold-const.c (fold_addr_of_array_ref_difference): Properly
 	convert operands before folding a MINUS_EXPR.
 	(fold_binary_loc): Move simplification of MINUS_EXPR on

gcc/optabs.c

@@ -1748,11 +1748,12 @@ expand_binop (machine_mode mode, optab binoptab, rtx op0, rtx op1,
       insns = get_insns ();
       end_sequence ();
 
+      bool trapv = trapv_binoptab_p (binoptab);
       target = gen_reg_rtx (mode);
       emit_libcall_block_1 (insns, target, value,
-			    gen_rtx_fmt_ee (optab_to_code (binoptab),
-					    mode, op0, op1),
-			    trapv_binoptab_p (binoptab));
+			    trapv ? NULL_RTX
+			    : gen_rtx_fmt_ee (optab_to_code (binoptab),
+					      mode, op0, op1), trapv);
 
       return target;
     }
@@ -2880,13 +2881,19 @@ expand_unop (machine_mode mode, optab unoptab, rtx op0, rtx target,
       end_sequence ();
 
       target = gen_reg_rtx (outmode);
-      eq_value = gen_rtx_fmt_e (optab_to_code (unoptab), mode, op0);
-      if (GET_MODE_SIZE (outmode) < GET_MODE_SIZE (mode))
-	eq_value = simplify_gen_unary (TRUNCATE, outmode, eq_value, mode);
-      else if (GET_MODE_SIZE (outmode) > GET_MODE_SIZE (mode))
-	eq_value = simplify_gen_unary (ZERO_EXTEND, outmode, eq_value, mode);
-      emit_libcall_block_1 (insns, target, value, eq_value,
-			    trapv_unoptab_p (unoptab));
+      bool trapv = trapv_unoptab_p (unoptab);
+      if (trapv)
+	eq_value = NULL_RTX;
+      else
+	{
+	  eq_value = gen_rtx_fmt_e (optab_to_code (unoptab), mode, op0);
+	  if (GET_MODE_SIZE (outmode) < GET_MODE_SIZE (mode))
+	    eq_value = simplify_gen_unary (TRUNCATE, outmode, eq_value, mode);
+	  else if (GET_MODE_SIZE (outmode) > GET_MODE_SIZE (mode))
+	    eq_value = simplify_gen_unary (ZERO_EXTEND,
+					   outmode, eq_value, mode);
+	}
+      emit_libcall_block_1 (insns, target, value, eq_value, trapv);
 
       return target;
     }
@@ -3573,7 +3580,8 @@ emit_libcall_block_1 (rtx_insn *insns, rtx target, rtx result, rtx equiv,
     }
 
   last = emit_move_insn (target, result);
-  set_dst_reg_note (last, REG_EQUAL, copy_rtx (equiv), target);
+  if (equiv)
+    set_dst_reg_note (last, REG_EQUAL, copy_rtx (equiv), target);
 
   if (final_dest != target)
     emit_move_insn (final_dest, target);

gcc/testsuite/ChangeLog

+2015-10-22  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/68046
+	PR middle-end/61893
+	* gcc.dg/torture/ftrapv-2.c: New testcase.
+
 2015-10-22  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
 
 	PR target/68015

gcc/testsuite/gcc.dg/torture/ftrapv-2.c

+/* { dg-do run } */
+/* With -flto this degenerates to constant folding which doesn't work.  */
+/* { dg-skip-if "" { *-*-* } { "-flto" } { "" } } */
+/* { dg-additional-options "-ftrapv" } */
+/* { dg-require-effective-target trapping } */
+/* { dg-require-fork unused } */
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+/* Verify SImode operations properly trap.  PR middle-end/68046 */
+
+int i = 0x7fffffff;
+
+int main(void)
+{
+  pid_t child = fork ();
+  int status = 0;
+  if (child == 0)
+    {
+      volatile int x = i + 1 < i;
+      exit (0);
+    }
+  else if (child == -1)
+    return 0;
+  if (wait (&status) == child 
+      && status == 0)
+    abort ();
+  return 0;
+}