As PR 19020 has been closed ("let's ditch antiquated stuff and start afresh") - open a fresh bug. Using -ftrapv works with i368-gnu-linux: $ gcc -m32 -ftrapv hjfff.c && ./a.out Aborted (core dumped) $ But not on x86-64-gnu-linux: $ gcc -m64 -ftrapv hjfff.c && ./a.out $ In the debugger, one sees: a) i386: __addvsi3 (a=2147483647, b=1) at /home/tob/projects/gcc-trunk-checkout/libgcc/libgcc2.c:79 (gdb) pt a type = int b) x86-64: (gdb) __addvdi3 (a=2147483647, b=1) at /home/tob/projects/gcc-trunk-checkout/libgcc/libgcc2.c:82 (gdb) pt a type = long int Thus, there is no overflow in that function. THUS: On i386 it calls the correct function but on x86-64 it should call the SI not the DI function. * * * For long/LONG_MAX, one has again: a) -m32 __addvsi3 (a=2147483647, b=1) at /home/tob/projects/gcc-trunk-checkout/libgcc/libgcc2.c:79 79 { (gdb) pt a type = int b) -m64 __addvdi3 (a=9223372036854775807, b=1) at /home/tob/projects/gcc-trunk-checkout/libgcc/libgcc2.c:82 82 if (b >= 0 ? w < a : w > a) (gdb) pt a type = long int THUS: x86-64 calls correctly the DI function but i386 wrongly the SI function * * * long long / LLONG_MAX: a) -m32: __addvdi3 (a=9223372036854775807, b=1) at /home/tob/projects/gcc-trunk-checkout/libgcc/libgcc2.c:82 82 if (b >= 0 ? w < a : w > a) (gdb) pt a type = long int b) -m64 __addvdi3 (a=9223372036854775807, b=1) at /home/tob/projects/gcc-trunk-checkout/libgcc/libgcc2.c:82 82 if (b >= 0 ? w < a : w > a) (gdb) pt a type = long int THUS: Both x86-64 and i386 call the "long int" instead of the "long long" function. I had exepected a TI version, which does not seem to exist. * * * #include <limits.h> int __attribute__((noinline)) iaddv (int a, int b) { return a + b; } int main(void) { return iaddv (INT_MAX, 1); }
Confirmed, and I think we have a dup for this somewhere, we use OPTAB_LIB_WIDEN which is of course bogus for the trapv variants. See also PR52353 for similar mis-generic handling of trapv optabs. I'll take this one as well for now.
(In reply to comment #1) > Confirmed, and I think we have a dup for this somewhere. Maybe PR 35412 - its bug description is a bit unclear. Other bugs related to this PR have been closed, e.g. PR19020 ("fixed"), PR40143, PR39771, PR36868, PR27261 (duplicate). > I'll take this one as well for now. Thanks!
This seems to be by design, libgcc only provides >= word_mode trapping ops. Which means we'd need to expand this all using inline code: /* Like gen_libfunc, but verify that integer operation is involved. */ static void gen_int_libfunc (optab optable, const char *opname, char suffix, 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 || mode < word_mode || GET_MODE_BITSIZE (mode) > maxsize) return; oops. Otherwise a simple Index: gcc/expr.c =================================================================== --- gcc/expr.c (revision 184918) +++ gcc/expr.c (working copy) @@ -8938,7 +8938,9 @@ 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. */ should have worked. So, it's a "not implemented thing" currently ... unlike to change until somebody implements the ftrapv proposal from Joseph.
*** Bug 54846 has been marked as a duplicate of this bug. ***
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.
Author: rguenth Date: Mon Jul 28 08:47:38 2014 New Revision: 213117 URL: https://gcc.gnu.org/viewcvs?rev=213117&root=gcc&view=rev Log: 2014-07-28 Richard Biener <rguenther@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. Added: trunk/gcc/testsuite/gcc.dg/torture/ftrapv-1.c Modified: trunk/gcc/ChangeLog trunk/gcc/expr.c trunk/gcc/optabs.c trunk/gcc/testsuite/ChangeLog
Fixed on trunk.
Author: rguenth Date: Tue Jul 29 11:10:49 2014 New Revision: 213153 URL: https://gcc.gnu.org/viewcvs?rev=213153&root=gcc&view=rev Log: 2014-07-29 Richard Biener <rguenther@suse.de> PR middle-end/52478 * expr.c (expand_expr_real_2): Revert last change. Modified: trunk/gcc/ChangeLog trunk/gcc/expr.c