[Bug middle-end/52478] -ftrapv calls the wrong functions in libgcc

["rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52478

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
It seems that the libgcc functions for SImode are present (at least on x86_64),
so sth like

Index: gcc/optabs.c
===================================================================
--- gcc/optabs.c        (revision 212970)
+++ gcc/optabs.c        (working copy)
@@ -5559,13 +5559,17 @@ gen_int_libfunc (optab optable, const ch
                 enum machine_mode mode)
 {
   int maxsize = 2 * BITS_PER_WORD;
+  int minsize = BITS_PER_WORD;

   if (GET_MODE_CLASS (mode) != MODE_INT)
     return;
   if (maxsize < LONG_LONG_TYPE_SIZE)
     maxsize = LONG_LONG_TYPE_SIZE;
-  if (GET_MODE_CLASS (mode) != MODE_INT
-      || GET_MODE_BITSIZE (mode) < BITS_PER_WORD
+  if (minsize > INT_TYPE_SIZE
+      && (trapv_binoptab_p (optable)
+         || trapv_unoptab_p (optable)))
+    minsize = INT_TYPE_SIZE;
+  if (GET_MODE_BITSIZE (mode) < minsize
       || GET_MODE_BITSIZE (mode) > maxsize)
     return;
   gen_libfunc (optable, opname, suffix, mode);
Index: gcc/expr.c
===================================================================
--- gcc/expr.c  (revision 212970)
+++ gcc/expr.c  (working copy)
@@ -9212,7 +9212,9 @@ expand_expr_real_2 (sepops ops, rtx targ
   if (modifier == EXPAND_STACK_PARM)
     target = 0;
   temp = expand_binop (mode, this_optab, op0, op1, target,
-                      unsignedp, OPTAB_LIB_WIDEN);
+                      unsignedp,
+                      trapv_binoptab_p (this_optab)
+                      ? OPTAB_LIB : OPTAB_LIB_WIDEN);
   gcc_assert (temp);
   /* Bitwise operations do not need bitfield reduction as we expect their
      operands being properly truncated.  */

makes the testcase pass.