ShawnZhong created this revision.
ShawnZhong added a reviewer: rsmith.
ShawnZhong added a project: clang.
Herald added a project: All.
ShawnZhong requested review of this revision.
Herald added a subscriber: cfe-commits.
Fix https://github.com/llvm/llvm-project/issues/53253
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D131255
Files:
clang/lib/Sema/SemaChecking.cpp
clang/test/Sema/constant-conversion.c
Index: clang/test/Sema/constant-conversion.c
===================================================================
--- clang/test/Sema/constant-conversion.c
+++ clang/test/Sema/constant-conversion.c
@@ -131,3 +131,15 @@
s.a = -9; // expected-warning{{implicit truncation from 'int' to bit-field
changes value from -9 to 7}}
s.a = 16; // expected-warning{{implicit truncation from 'int' to bit-field
changes value from 16 to 0}}
}
+
+void test11(void) {
+ struct S {
+ signed char c : 1; // the only valid values are 0 and -1
+ } s;
+
+ s.c = -2; // expected-warning {{implicit conversion from 'int' to 'char'
changes value from -2 to 0}}
+ s.c = -1; // no-warning
+ s.c = 0; // no-warning
+ s.c = 1; // expected-warning {{implicit conversion from 'int' to 'char'
changes value from 1 to -1}}
+ s.c = 2; // expected-warning {{implicit conversion from 'int' to 'char'
changes value from 2 to 0}}
+}
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -13067,11 +13067,6 @@
if (llvm::APSInt::isSameValue(Value, TruncatedValue))
return false;
- // Special-case bitfields of width 1: booleans are naturally 0/1, and
- // therefore don't strictly fit into a signed bitfield of width 1.
- if (FieldWidth == 1 && Value == 1)
- return false;
-
std::string PrettyValue = toString(Value, 10);
std::string PrettyTrunc = toString(TruncatedValue, 10);
Index: clang/test/Sema/constant-conversion.c
===================================================================
--- clang/test/Sema/constant-conversion.c
+++ clang/test/Sema/constant-conversion.c
@@ -131,3 +131,15 @@
s.a = -9; // expected-warning{{implicit truncation from 'int' to bit-field changes value from -9 to 7}}
s.a = 16; // expected-warning{{implicit truncation from 'int' to bit-field changes value from 16 to 0}}
}
+
+void test11(void) {
+ struct S {
+ signed char c : 1; // the only valid values are 0 and -1
+ } s;
+
+ s.c = -2; // expected-warning {{implicit conversion from 'int' to 'char' changes value from -2 to 0}}
+ s.c = -1; // no-warning
+ s.c = 0; // no-warning
+ s.c = 1; // expected-warning {{implicit conversion from 'int' to 'char' changes value from 1 to -1}}
+ s.c = 2; // expected-warning {{implicit conversion from 'int' to 'char' changes value from 2 to 0}}
+}
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -13067,11 +13067,6 @@
if (llvm::APSInt::isSameValue(Value, TruncatedValue))
return false;
- // Special-case bitfields of width 1: booleans are naturally 0/1, and
- // therefore don't strictly fit into a signed bitfield of width 1.
- if (FieldWidth == 1 && Value == 1)
- return false;
-
std::string PrettyValue = toString(Value, 10);
std::string PrettyTrunc = toString(TruncatedValue, 10);
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