xbolva00 updated this revision to Diff 167869.
xbolva00 marked an inline comment as done.
https://reviews.llvm.org/D52137
Files:
include/clang/Basic/DiagnosticSemaKinds.td
lib/Sema/SemaChecking.cpp
test/Sema/unary-minus-integer-impcast.c
Index: test/Sema/unary-minus-integer-impcast.c
===================================================================
--- test/Sema/unary-minus-integer-impcast.c
+++ test/Sema/unary-minus-integer-impcast.c
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 %s -verify -Wconversion -fsyntax-only -triple
x86_64-pc-linux-gnu
+// RUN: %clang_cc1 %s -verify -Wconversion -fsyntax-only -triple
i386-pc-linux-gnu
+
+void test(void) {
+ unsigned int a = 1;
+
+ unsigned long long b = -a; // expected-warning {{higher order bits are
zeroes after implicit conversion}}
+ long long c = -a; // expected-warning {{the resulting value is
always non-negative after implicit conversion}}
+
+ unsigned long b2 = -a;
+#ifdef __x86_64__
+// expected-warning@-2 {{higher order bits are zeroes after implicit
conversion}}
+#endif
+ long c2 = -a;
+#ifdef __x86_64__
+// expected-warning@-2 {{the resulting value is always non-negative after
implicit conversion}}
+#else
+// expected-warning@-4 {{implicit conversion changes signedness: 'unsigned
int' to 'long'}}
+#endif
+}
Index: lib/Sema/SemaChecking.cpp
===================================================================
--- lib/Sema/SemaChecking.cpp
+++ lib/Sema/SemaChecking.cpp
@@ -10896,6 +10896,19 @@
return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision);
}
+ if (TargetRange.Width > SourceRange.Width) {
+ if (auto *UO = dyn_cast<UnaryOperator>(E))
+ if (UO->getOpcode() == UO_Minus)
+ if (Source->isUnsignedIntegerType()) {
+ if (Target->isUnsignedIntegerType())
+ return DiagnoseImpCast(S, E, T, CC,
+ diag::warn_impcast_high_order_zero_bits);
+ if (Target->isSignedIntegerType())
+ return DiagnoseImpCast(S, E, T, CC,
+ diag::warn_impcast_nonnegative_result);
+ }
+ }
+
if (TargetRange.Width == SourceRange.Width && !TargetRange.NonNegative &&
SourceRange.NonNegative && Source->isSignedIntegerType()) {
// Warn when doing a signed to signed conversion, warn if the positive
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -3197,6 +3197,12 @@
def warn_impcast_integer_precision : Warning<
"implicit conversion loses integer precision: %0 to %1">,
InGroup<Conversion>, DefaultIgnore;
+def warn_impcast_high_order_zero_bits : Warning<
+ "higher order bits are zeroes after implicit conversion">,
+ InGroup<Conversion>, DefaultIgnore;
+def warn_impcast_nonnegative_result : Warning<
+ "the resulting value is always non-negative after implicit conversion">,
+ InGroup<SignConversion>, DefaultIgnore;
def warn_impcast_integer_64_32 : Warning<
"implicit conversion loses integer precision: %0 to %1">,
InGroup<Shorten64To32>, DefaultIgnore;
Index: test/Sema/unary-minus-integer-impcast.c
===================================================================
--- test/Sema/unary-minus-integer-impcast.c
+++ test/Sema/unary-minus-integer-impcast.c
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 %s -verify -Wconversion -fsyntax-only -triple x86_64-pc-linux-gnu
+// RUN: %clang_cc1 %s -verify -Wconversion -fsyntax-only -triple i386-pc-linux-gnu
+
+void test(void) {
+ unsigned int a = 1;
+
+ unsigned long long b = -a; // expected-warning {{higher order bits are zeroes after implicit conversion}}
+ long long c = -a; // expected-warning {{the resulting value is always non-negative after implicit conversion}}
+
+ unsigned long b2 = -a;
+#ifdef __x86_64__
+// expected-warning@-2 {{higher order bits are zeroes after implicit conversion}}
+#endif
+ long c2 = -a;
+#ifdef __x86_64__
+// expected-warning@-2 {{the resulting value is always non-negative after implicit conversion}}
+#else
+// expected-warning@-4 {{implicit conversion changes signedness: 'unsigned int' to 'long'}}
+#endif
+}
Index: lib/Sema/SemaChecking.cpp
===================================================================
--- lib/Sema/SemaChecking.cpp
+++ lib/Sema/SemaChecking.cpp
@@ -10896,6 +10896,19 @@
return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision);
}
+ if (TargetRange.Width > SourceRange.Width) {
+ if (auto *UO = dyn_cast<UnaryOperator>(E))
+ if (UO->getOpcode() == UO_Minus)
+ if (Source->isUnsignedIntegerType()) {
+ if (Target->isUnsignedIntegerType())
+ return DiagnoseImpCast(S, E, T, CC,
+ diag::warn_impcast_high_order_zero_bits);
+ if (Target->isSignedIntegerType())
+ return DiagnoseImpCast(S, E, T, CC,
+ diag::warn_impcast_nonnegative_result);
+ }
+ }
+
if (TargetRange.Width == SourceRange.Width && !TargetRange.NonNegative &&
SourceRange.NonNegative && Source->isSignedIntegerType()) {
// Warn when doing a signed to signed conversion, warn if the positive
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -3197,6 +3197,12 @@
def warn_impcast_integer_precision : Warning<
"implicit conversion loses integer precision: %0 to %1">,
InGroup<Conversion>, DefaultIgnore;
+def warn_impcast_high_order_zero_bits : Warning<
+ "higher order bits are zeroes after implicit conversion">,
+ InGroup<Conversion>, DefaultIgnore;
+def warn_impcast_nonnegative_result : Warning<
+ "the resulting value is always non-negative after implicit conversion">,
+ InGroup<SignConversion>, DefaultIgnore;
def warn_impcast_integer_64_32 : Warning<
"implicit conversion loses integer precision: %0 to %1">,
InGroup<Shorten64To32>, DefaultIgnore;
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