public inbox for gcc-cvs@sourceware.org
help / color / mirror / Atom feed
* [gcc(refs/vendors/redhat/heads/gcc-10-branch)] c++: Fix -Wtype-limits in templates.
@ 2020-01-30 20:59 Jakub Jelinek
0 siblings, 0 replies; only message in thread
From: Jakub Jelinek @ 2020-01-30 20:59 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:4dd468a042e19ef0fdbb1c53ca4060d4cb4972c5
commit 4dd468a042e19ef0fdbb1c53ca4060d4cb4972c5
Author: Jason Merrill <jason@redhat.com>
Date: Thu Jan 30 13:12:05 2020 -0500
c++: Fix -Wtype-limits in templates.
When instantiating a template tsubst_copy_and_build suppresses -Wtype-limits
warnings about e.g. == always being false because it might not always be
false for an instantiation with other template arguments. But we should
warn if the operands don't depend on template arguments.
PR c++/82521
* pt.c (tsubst_copy_and_build) [EQ_EXPR]: Only suppress warnings if
the expression was dependent before substitution.
Diff:
---
gcc/cp/ChangeLog | 6 ++++++
gcc/cp/pt.c | 12 ++++++++----
gcc/testsuite/g++.dg/warn/Wtype-limits3.C | 13 +++++++++++++
3 files changed, 27 insertions(+), 4 deletions(-)
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index a402b97..f260d5d 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-01-29 Jason Merrill <jason@redhat.com>
+
+ PR c++/82521
+ * pt.c (tsubst_copy_and_build) [EQ_EXPR]: Only suppress warnings if
+ the expression was dependent before substitution.
+
2020-01-30 Bin Cheng <bin.cheng@linux.alibaba.com>
* coroutines.cc (act_des_fn): New.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 416ff63..40ff3c3 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -19279,10 +19279,14 @@ tsubst_copy_and_build (tree t,
case MEMBER_REF:
case DOTSTAR_EXPR:
{
- warning_sentinel s1(warn_type_limits);
- warning_sentinel s2(warn_div_by_zero);
- warning_sentinel s3(warn_logical_op);
- warning_sentinel s4(warn_tautological_compare);
+ /* If T was type-dependent, suppress warnings that depend on the range
+ of the types involved. */
+ bool was_dep = uses_template_parms (t);
+ warning_sentinel s1(warn_type_limits, was_dep);
+ warning_sentinel s2(warn_div_by_zero, was_dep);
+ warning_sentinel s3(warn_logical_op, was_dep);
+ warning_sentinel s4(warn_tautological_compare, was_dep);
+
tree op0 = RECUR (TREE_OPERAND (t, 0));
tree op1 = RECUR (TREE_OPERAND (t, 1));
tree r = build_x_binary_op
diff --git a/gcc/testsuite/g++.dg/warn/Wtype-limits3.C b/gcc/testsuite/g++.dg/warn/Wtype-limits3.C
new file mode 100644
index 0000000..b9059ac
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wtype-limits3.C
@@ -0,0 +1,13 @@
+// PR c++/82521
+// { dg-additional-options "-Wtype-limits" }
+
+template <typename T>
+const char * g(const unsigned char value)
+{
+ return value == -1 ? "-1" : "no"; // { dg-warning "always false" }
+}
+
+int main()
+{
+ g<int>(-1);
+}
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2020-01-30 20:59 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-01-30 20:59 [gcc(refs/vendors/redhat/heads/gcc-10-branch)] c++: Fix -Wtype-limits in templates Jakub Jelinek
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).