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| author | Paolo Carlini <paolo.carlini@oracle.com> | 2016-11-04 18:58:53 +0000 |
|---|---|---|
| committer | Paolo Carlini <paolo@gcc.gnu.org> | 2016-11-04 18:58:53 +0000 |
| commit | 6e3ae7e6f5699430cdedd1ca2a7b5cfa020171aa (patch) | |
| tree | bb6be5027945eeab60910722852a70025d9c6d43 /gcc | |
| parent | fff6ed28b29e9fff2026ee79446f2e565ef63806 (diff) | |
| download | gcc-6e3ae7e6f5699430cdedd1ca2a7b5cfa020171aa.zip gcc-6e3ae7e6f5699430cdedd1ca2a7b5cfa020171aa.tar.gz gcc-6e3ae7e6f5699430cdedd1ca2a7b5cfa020171aa.tar.bz2 | |
re PR c++/67980 (left shift count is negative [-Wshift-count-negative] generated for unreachable code)
/cp
2016-11-04 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/67980
* pt.c (tsubst_expr, case IF_STMT): Use fold_non_dependent_expr
to suppress unwanted warnings.
/testsuite
2016-11-04 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/67980
* g++.dg/cpp1y/pr67980.C: New.
From-SVN: r241858
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/cp/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/cp/pt.c | 14 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp1y/pr67980.C | 23 |
4 files changed, 47 insertions, 1 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 544de43..e567fef 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,9 @@ +2016-11-04 Paolo Carlini <paolo.carlini@oracle.com> + + PR c++/67980 + * pt.c (tsubst_expr, case IF_STMT): Use fold_non_dependent_expr + to suppress unwanted warnings. + 2016-11-03 Jason Merrill <jason@redhat.com> PR c++/78198 diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index e513448..c8d4a06 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -15437,15 +15437,27 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl, if (IF_STMT_CONSTEXPR_P (t) && integer_zerop (tmp)) /* Don't instantiate the THEN_CLAUSE. */; else - RECUR (THEN_CLAUSE (t)); + { + bool inhibit = integer_zerop (fold_non_dependent_expr (tmp)); + if (inhibit) + ++c_inhibit_evaluation_warnings; + RECUR (THEN_CLAUSE (t)); + if (inhibit) + --c_inhibit_evaluation_warnings; + } finish_then_clause (stmt); if (IF_STMT_CONSTEXPR_P (t) && integer_nonzerop (tmp)) /* Don't instantiate the ELSE_CLAUSE. */; else if (ELSE_CLAUSE (t)) { + bool inhibit = integer_nonzerop (fold_non_dependent_expr (tmp)); begin_else_clause (stmt); + if (inhibit) + ++c_inhibit_evaluation_warnings; RECUR (ELSE_CLAUSE (t)); + if (inhibit) + --c_inhibit_evaluation_warnings; finish_else_clause (stmt); } diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 910b8d2..eae75f1 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2016-11-04 Paolo Carlini <paolo.carlini@oracle.com> + + PR c++/67980 + * g++.dg/cpp1y/pr67980.C: New. + 2016-11-04 Bill Schmidt <wschmidt@linux.vnet.ibm.com> * gcc.target/powerpc/fold-vec-add-1.c: New. diff --git a/gcc/testsuite/g++.dg/cpp1y/pr67980.C b/gcc/testsuite/g++.dg/cpp1y/pr67980.C new file mode 100644 index 0000000..1b81545 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1y/pr67980.C @@ -0,0 +1,23 @@ +// { dg-do compile { target c++14 } } + +template <int Y, class T> +constexpr T cpp14_constexpr_then(T value) { + if (Y < 0) + return (value << -Y); + else + return 0; +} + +template <int Y, class T> +constexpr T cpp14_constexpr_else(T value) { + if (Y > 0) + return 0; + else + return (value << -Y); +} + +int main() +{ + cpp14_constexpr_then<1>(0); + cpp14_constexpr_else<1>(0); +} |