ziangwan updated this revision to Diff 209611.
ziangwan added a comment.
Fix spelling / comment / naming issues.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D64666/new/
https://reviews.llvm.org/D64666
Files:
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/lib/Driver/ToolChains/Arch/AArch64.cpp
clang/lib/Sema/SemaChecking.cpp
clang/test/Sema/conversion.c
clang/test/Sema/ext_vector_casts.c
clang/test/Sema/implicit-float-conversion.c
Index: clang/test/Sema/implicit-float-conversion.c
===================================================================
--- /dev/null
+++ clang/test/Sema/implicit-float-conversion.c
@@ -0,0 +1,30 @@
+// RUN: %clang_cc1 %s -verify -Wno-conversion -Wimplicit-float-conversion
+
+
+long testReturn(long a, float b) {
+ return a + b; // expected-warning {{implicit conversion from 'long' to 'float' may loses integer precision}}
+}
+
+
+void testAssignment() {
+ float f = 222222;
+ double b = 222222222222L;
+
+ float ff = 222222222222L; // expected-warning {{implicit conversion from 'long' to 'float' changes value}}
+
+ long l = 222222222222L;
+ float fff = l; // expected-warning {{implicit conversion from 'long' to 'float' may loses integer precision}}
+}
+
+
+void testExpression() {
+ float a = 0.0f;
+ float b = 222222222222L + a; // expected-warning {{implicit conversion from 'long' to 'float' changes value}}
+ float c = 22222222 + 22222223; // expected-warning {{implicit conversion from 'int' to 'float' changes value}}
+
+ int i = 0;
+ float d = i + a; // expected-warning {{implicit conversion from 'int' to 'float' may loses integer precision}}
+
+ double e = 0.0;
+ double f = i + e;
+}
Index: clang/test/Sema/ext_vector_casts.c
===================================================================
--- clang/test/Sema/ext_vector_casts.c
+++ clang/test/Sema/ext_vector_casts.c
@@ -115,12 +115,12 @@
vl = vl + t; // expected-warning {{implicit conversion loses integer precision}}
vf = 1 + vf;
- vf = l + vf;
+ vf = l + vf; // expected-warning {{implicit conversion from 'long' to 'float2' (vector of 2 'float' values) may loses integer precision}}
vf = 2.0 + vf;
vf = d + vf; // expected-warning {{implicit conversion loses floating-point precision}}
- vf = vf + 0xffffffff;
+ vf = vf + 0xffffffff; // expected-warning {{implicit conversion from 'unsigned int' to 'float2' (vector of 2 'float' values) changes value}}
vf = vf + 2.1; // expected-warning {{implicit conversion loses floating-point precision}}
- vd = l + vd;
- vd = vd + t;
+ vd = l + vd; // expected-warning {{implicit conversion from 'long' to 'double2' (vector of 2 'double' values) may loses integer precision}}
+ vd = vd + t; // expected-warning {{implicit conversion from '__uint128_t' (aka 'unsigned __int128') to 'double2' (vector of 2 'double' values) may loses integer precision}}
}
Index: clang/test/Sema/conversion.c
===================================================================
--- clang/test/Sema/conversion.c
+++ clang/test/Sema/conversion.c
@@ -233,7 +233,7 @@
takes_int(v);
takes_long(v);
takes_longlong(v);
- takes_float(v);
+ takes_float(v); // expected-warning {{implicit conversion from 'int' to 'float' may loses integer precision}}
takes_double(v);
takes_longdouble(v);
}
@@ -244,8 +244,8 @@
takes_int(v); // expected-warning {{implicit conversion loses integer precision}}
takes_long(v);
takes_longlong(v);
- takes_float(v);
- takes_double(v);
+ takes_float(v); // expected-warning {{implicit conversion from 'long' to 'float' may loses integer precision}}
+ takes_double(v); // expected-warning {{implicit conversion from 'long' to 'double' may loses integer precision}}
takes_longdouble(v);
}
@@ -255,8 +255,8 @@
takes_int(v); // expected-warning {{implicit conversion loses integer precision}}
takes_long(v);
takes_longlong(v);
- takes_float(v);
- takes_double(v);
+ takes_float(v); // expected-warning {{implicit conversion from 'long long' to 'float' may loses integer precision}}
+ takes_double(v); // expected-warning {{implicit conversion from 'long long' to 'double' may loses integer precision}}
takes_longdouble(v);
}
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -11400,6 +11400,49 @@
}
}
+ // If we are casting an integer type to a floating point type, we might
+ // lose accuracy if the floating point type has a narrower significand
+ // than the floating point type. Issue warnings for that accuracy loss.
+ if (SourceBT && TargetBT &&
+ SourceBT->isIntegerType() && TargetBT->isFloatingType()) {
+ // Determine the number of precision bits in the source integer type.
+ IntRange SourceRange = GetExprRange(S.Context, E, S.isConstantEvaluated());
+ unsigned int SourcePrecision = SourceRange.Width;
+
+ // Determine the number of precision bits in the target floating point type
+ // Also create a APFloat object to represent the converted value.
+ unsigned int TargetPrecision = llvm::APFloatBase::semanticsPrecision(
+ S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)));
+ llvm::APFloat TargetFloatValue(
+ S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)));
+
+ if (SourcePrecision > 0 && TargetPrecision > 0 &&
+ SourcePrecision > TargetPrecision) {
+ // If the source integer is a constant, then the implicit conversion
+ // definitely lose precision. Otherwise, the implicit conversion
+ // *may* lose precision.
+ llvm::APSInt SourceInt;
+ if (E->isIntegerConstantExpr(SourceInt, S.Context)) {
+ std::string PrettySourceValue = SourceInt.toString(10);
+ TargetFloatValue.convertFromAPInt(SourceInt,
+ SourceBT->isSignedInteger(), llvm::APFloat::rmTowardZero);
+ SmallString<32> PrettyTargetValue;
+ TargetFloatValue.toString(PrettyTargetValue,
+ TargetPrecision);
+
+ S.DiagRuntimeBehavior(
+ E->getExprLoc(), E,
+ S.PDiag(diag::warn_impcast_integer_float_precision_constant)
+ << PrettySourceValue << PrettyTargetValue
+ << E->getType() << T
+ << E->getSourceRange() << clang::SourceRange(CC));
+ } else {
+ DiagnoseImpCast(S, E, T, CC,
+ diag::warn_impcast_integer_float_precision);
+ }
+ }
+ }
+
DiagnoseNullConversion(S, E, T, CC);
S.DiscardMisalignedMemberAddress(Target, E);
Index: clang/lib/Driver/ToolChains/Arch/AArch64.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Arch/AArch64.cpp
+++ clang/lib/Driver/ToolChains/Arch/AArch64.cpp
@@ -88,7 +88,7 @@
unsigned Extension = llvm::AArch64::getDefaultExtensions(CPU, ArchKind);
if (!llvm::AArch64::getExtensionFeatures(Extension, Features))
return false;
- }
+ }
if (Split.second.size() && !DecodeAArch64Features(D, Split.second, Features))
return false;
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3241,6 +3241,13 @@
"the only well defined values for BOOL are YES and NO">,
InGroup<ObjCBoolConstantConversion>;
+def warn_impcast_integer_float_precision : Warning<
+ "implicit conversion from %0 to %1 may loses integer precision">,
+ InGroup<ImplicitFloatConversion>, DefaultIgnore;
+def warn_impcast_integer_float_precision_constant : Warning<
+ "implicit conversion from %2 to %3 changes value from %0 to %1">,
+ InGroup<ImplicitFloatConversion>, DefaultIgnore;
+
def warn_impcast_fixed_point_range : Warning<
"implicit conversion from %0 cannot fit within the range of values for %1">,
InGroup<ImplicitFixedPointConversion>;
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