| Message ID | 20140325213432.GB1817@tucnak.redhat.com |
|---|---|
| State | New |
| Headers | show |
On Tue, 25 Mar 2014, Jakub Jelinek wrote: > On Tue, Mar 25, 2014 at 10:43:02AM +0100, Richard Biener wrote: > > Yes, all transforms in fold-const would be invalid if the result doesn't > > behave in the same way wrt overflow. Thus you really should instrument > > ABS_EXPR - you can treat it as A > 0 ? A : -A if that simplifies it. > > > > I don't like the conditions that disable stuff based on sanitization. > > > > Instrumenting ABS_EXPR shouldn't be too difficult. > > Ok, here is a patch that does that. Tested on x86_64-linux and i686-linux. > Ok for trunk? Ok. Thanks, Richard. > 2014-03-25 Jakub Jelinek <jakub@redhat.com> > > PR sanitizer/60636 > * ubsan.c (instrument_si_overflow): Instrument ABS_EXPR. > > * c-c++-common/ubsan/pr60636.c: New test. > > --- gcc/ubsan.c.jj 2014-03-19 14:44:23.000000000 +0100 > +++ gcc/ubsan.c 2014-03-25 13:00:35.052459078 +0100 > @@ -737,6 +737,21 @@ instrument_si_overflow (gimple_stmt_iter > gimple_call_set_lhs (g, lhs); > gsi_replace (&gsi, g, false); > break; > + case ABS_EXPR: > + /* Transform i = ABS_EXPR<u>; > + into > + _N = UBSAN_CHECK_SUB (0, u); > + i = ABS_EXPR<_N>; */ > + a = build_int_cst (lhstype, 0); > + b = gimple_assign_rhs1 (stmt); > + g = gimple_build_call_internal (IFN_UBSAN_CHECK_SUB, 2, a, b); > + a = make_ssa_name (lhstype, NULL); > + gimple_call_set_lhs (g, a); > + gimple_set_location (g, gimple_location (stmt)); > + gsi_insert_before (&gsi, g, GSI_SAME_STMT); > + gimple_assign_set_rhs1 (stmt, a); > + update_stmt (stmt); > + break; > default: > break; > } > --- gcc/testsuite/c-c++-common/ubsan/pr60636.c.jj 2014-03-25 12:31:29.458629212 +0100 > +++ gcc/testsuite/c-c++-common/ubsan/pr60636.c 2014-03-25 12:31:29.458629212 +0100 > @@ -0,0 +1,15 @@ > +/* PR sanitizer/60636 */ > +/* { dg-do run } */ > +/* { dg-options "-fsanitize=undefined" } */ > + > +volatile long long int a; > + > +int > +main () > +{ > + long long int u = -__LONG_LONG_MAX__ - 1; > + a = u > 0 ? u : -u; > + return 0; > +} > + > +/* { dg-output "negation of -9223372036854775808 cannot be represented in type 'long long int'" } */ > > > Jakub > >
--- gcc/ubsan.c.jj 2014-03-19 14:44:23.000000000 +0100 +++ gcc/ubsan.c 2014-03-25 13:00:35.052459078 +0100 @@ -737,6 +737,21 @@ instrument_si_overflow (gimple_stmt_iter gimple_call_set_lhs (g, lhs); gsi_replace (&gsi, g, false); break; + case ABS_EXPR: + /* Transform i = ABS_EXPR<u>; + into + _N = UBSAN_CHECK_SUB (0, u); + i = ABS_EXPR<_N>; */ + a = build_int_cst (lhstype, 0); + b = gimple_assign_rhs1 (stmt); + g = gimple_build_call_internal (IFN_UBSAN_CHECK_SUB, 2, a, b); + a = make_ssa_name (lhstype, NULL); + gimple_call_set_lhs (g, a); + gimple_set_location (g, gimple_location (stmt)); + gsi_insert_before (&gsi, g, GSI_SAME_STMT); + gimple_assign_set_rhs1 (stmt, a); + update_stmt (stmt); + break; default: break; } --- gcc/testsuite/c-c++-common/ubsan/pr60636.c.jj 2014-03-25 12:31:29.458629212 +0100 +++ gcc/testsuite/c-c++-common/ubsan/pr60636.c 2014-03-25 12:31:29.458629212 +0100 @@ -0,0 +1,15 @@ +/* PR sanitizer/60636 */ +/* { dg-do run } */ +/* { dg-options "-fsanitize=undefined" } */ + +volatile long long int a; + +int +main () +{ + long long int u = -__LONG_LONG_MAX__ - 1; + a = u > 0 ? u : -u; + return 0; +} + +/* { dg-output "negation of -9223372036854775808 cannot be represented in type 'long long int'" } */