The following fixes one of the most annoying parts of non-working -ftrapv,
namely that we only support >= word_mode trappings (quite annoying on
64bit archs where 'int' is not handled). At least on x86_64 libgcc
has all the libfuncs available for SImode so the following patch
arranges for them to be used. RFC because I don't know whether
they are there by accident... (and thus the patch adds a requirement
that is not met by other targets - but a link error is better than
-ftrapv failure?)
The testcase relies on fork() to be able to capture both inline
and out-of-line trapv sequences. dg-require-fork is unused but
present, so I use it. I suppose we can restrict the testcase
to a few targets manually as well - not sure, any preferences?
At least the obvious testcase from PR52478 now works (until
you hit constant folding ... see PR61893 I just opened).
Bootstrap and regtest running on x86_64-unknown-linux-gnu, ok
for trunk?
Thanks,
Richard.
2014-07-24 Richard Biener <rguent...@suse.de>
PR middle-end/52478
* optabs.c (gen_int_libfunc): For -ftrapv libfuncs make
sure to register SImode ones, not only >= word_mode ones.
* expr.c (expand_expr_real_2): When expanding -ftrapv
binops do not use OPTAB_LIB_WIDEN.
* gcc.dg/torture/ftrapv-1.c: New testcase.
Index: gcc/optabs.c
===================================================================
*** gcc/optabs.c (revision 212970)
--- gcc/optabs.c (working copy)
*************** gen_int_libfunc (optab optable, const ch
*** 5559,5571 ****
enum machine_mode mode)
{
int maxsize = 2 * 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
|| GET_MODE_BITSIZE (mode) > maxsize)
return;
gen_libfunc (optable, opname, suffix, mode);
--- 5559,5575 ----
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 (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)
*************** expand_expr_real_2 (sepops ops, rtx targ
*** 9212,9218 ****
if (modifier == EXPAND_STACK_PARM)
target = 0;
temp = expand_binop (mode, this_optab, op0, op1, target,
! unsignedp, OPTAB_LIB_WIDEN);
gcc_assert (temp);
/* Bitwise operations do not need bitfield reduction as we expect their
operands being properly truncated. */
--- 9212,9220 ----
if (modifier == EXPAND_STACK_PARM)
target = 0;
temp = expand_binop (mode, this_optab, op0, op1, target,
! 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. */
Index: gcc/testsuite/gcc.dg/torture/ftrapv-1.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/ftrapv-1.c (revision 0)
--- gcc/testsuite/gcc.dg/torture/ftrapv-1.c (working copy)
***************
*** 0 ****
--- 1,37 ----
+ /* { dg-do run } */
+ /* { dg-additional-options "-ftrapv" } */
+ /* { dg-require-effective-target trapping } */
+ /* { dg-require-fork } */
+
+ #include <stdlib.h>
+ #include <unistd.h>
+ #include <sys/types.h>
+ #include <sys/wait.h>
+
+ /* Verify SImode operations properly trap. PR middle-end/52478 */
+
+ /* Disallow inlining/cloning which would constant propagate and trigger
+ unrelated bugs. */
+
+ int __attribute__((noinline,noclone))
+ iaddv (int a, int b)
+ {
+ return a + b;
+ }
+
+ int main(void)
+ {
+ pid_t child = fork ();
+ int status = 0;
+ if (child == 0)
+ {
+ volatile int x = iaddv (__INT_MAX__, 1);
+ exit (0);
+ }
+ else if (child == -1)
+ return 0;
+ if (wait (&status) == child
+ && status == 0)
+ abort ();
+ return 0;
+ }
