Author: gbiv Date: Wed Oct 28 19:28:52 2015 New Revision: 251588 URL: http://llvm.org/viewvc/llvm-project?rev=251588&view=rev Log: [Sema] Implement -Wdouble-promotion for clang.
GCC has a warning called -Wdouble-promotion, which warns you when an implicit conversion increases the width of a floating point type. This is useful when writing code for architectures that can perform hardware FP ops on floats, but must fall back to software emulation for larger types (i.e. double, long double). This fixes PR15109 <https://llvm.org/bugs/show_bug.cgi?id=15109>. Thanks to Carl Norum for the patch! Added: cfe/trunk/test/Sema/warn-double-promotion.c Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td cfe/trunk/lib/Sema/SemaChecking.cpp Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=251588&r1=251587&r2=251588&view=diff ============================================================================== --- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original) +++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Wed Oct 28 19:28:52 2015 @@ -46,6 +46,7 @@ def BoolConversion : DiagGroup<"bool-con def IntConversion : DiagGroup<"int-conversion">; def EnumConversion : DiagGroup<"enum-conversion">; def FloatConversion : DiagGroup<"float-conversion">; +def DoublePromotion : DiagGroup<"double-promotion">; def EnumTooLarge : DiagGroup<"enum-too-large">; def UnsupportedNan : DiagGroup<"unsupported-nan">; def NonLiteralNullConversion : DiagGroup<"non-literal-null-conversion">; Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=251588&r1=251587&r2=251588&view=diff ============================================================================== --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original) +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Wed Oct 28 19:28:52 2015 @@ -2590,6 +2590,9 @@ def warn_impcast_complex_scalar : Warnin def warn_impcast_float_precision : Warning< "implicit conversion loses floating-point precision: %0 to %1">, InGroup<Conversion>, DefaultIgnore; +def warn_impcast_double_promotion : Warning< + "implicit conversion increases floating-point precision: %0 to %1">, + InGroup<DoublePromotion>, DefaultIgnore; def warn_impcast_float_integer : Warning< "implicit conversion turns floating-point number into integer: %0 to %1">, InGroup<FloatConversion>, DefaultIgnore; Modified: cfe/trunk/lib/Sema/SemaChecking.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=251588&r1=251587&r2=251588&view=diff ============================================================================== --- cfe/trunk/lib/Sema/SemaChecking.cpp (original) +++ cfe/trunk/lib/Sema/SemaChecking.cpp Wed Oct 28 19:28:52 2015 @@ -7217,6 +7217,14 @@ void CheckImplicitConversion(Sema &S, Ex return; DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision); + + } + // ... or possibly if we're increasing rank, too + else if (TargetBT->getKind() > SourceBT->getKind()) { + if (S.SourceMgr.isInSystemMacro(CC)) + return; + + DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_double_promotion); } return; } Added: cfe/trunk/test/Sema/warn-double-promotion.c URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/warn-double-promotion.c?rev=251588&view=auto ============================================================================== --- cfe/trunk/test/Sema/warn-double-promotion.c (added) +++ cfe/trunk/test/Sema/warn-double-promotion.c Wed Oct 28 19:28:52 2015 @@ -0,0 +1,34 @@ +// RUN: %clang_cc1 -verify -fsyntax-only %s -Wdouble-promotion + +float ReturnFloatFromDouble(double d) { + return d; +} + +float ReturnFloatFromLongDouble(long double ld) { + return ld; +} + +double ReturnDoubleFromLongDouble(long double ld) { + return ld; +} + +double ReturnDoubleFromFloat(float f) { + return f; //expected-warning{{implicit conversion increases floating-point precision: 'float' to 'double'}} +} + +long double ReturnLongDoubleFromFloat(float f) { + return f; //expected-warning{{implicit conversion increases floating-point precision: 'float' to 'long double'}} +} + +long double ReturnLongDoubleFromDouble(double d) { + return d; //expected-warning{{implicit conversion increases floating-point precision: 'double' to 'long double'}} +} + +void Convert(float f, double d, long double ld) { + d = f; //expected-warning{{implicit conversion increases floating-point precision: 'float' to 'double'}} + ld = f; //expected-warning{{implicit conversion increases floating-point precision: 'float' to 'long double'}} + ld = d; //expected-warning{{implicit conversion increases floating-point precision: 'double' to 'long double'}} + f = d; + f = ld; + d = ld; +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
