Author: Richard Smith Date: 2020-09-01T17:42:12-07:00 New Revision: 0ffbbce78de60f4f4d03d6ef97fe2f3bb4275e08
URL: https://github.com/llvm/llvm-project/commit/0ffbbce78de60f4f4d03d6ef97fe2f3bb4275e08 DIFF: https://github.com/llvm/llvm-project/commit/0ffbbce78de60f4f4d03d6ef97fe2f3bb4275e08.diff LOG: Don't take the expression range into account when looking for widening of a unary - expression. This fixes an issue where we'd produce bogus diagnostics, and also should recover ~0.3% compile time. Added: Modified: clang/lib/Sema/SemaChecking.cpp clang/test/Sema/unary-minus-integer-impcast.c Removed: ################################################################################ diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp index 2e07c8f63b79..f2b70be1d431 100644 --- a/clang/lib/Sema/SemaChecking.cpp +++ b/clang/lib/Sema/SemaChecking.cpp @@ -12064,13 +12064,13 @@ static void CheckImplicitConversion(Sema &S, Expr *E, QualType T, << E->getType()); } - IntRange MinSourceRange = + IntRange SourceTypeRange = + IntRange::forTargetOfCanonicalType(S.Context, Source); + IntRange LikelySourceRange = GetExprRange(S.Context, E, S.isConstantEvaluated(), /*Approximate*/ true); - IntRange MaxSourceRange = - GetExprRange(S.Context, E, S.isConstantEvaluated(), /*Approximate*/ false); IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target); - if (MinSourceRange.Width > TargetRange.Width) { + if (LikelySourceRange.Width > TargetRange.Width) { // If the source is a constant, use a default-on diagnostic. // TODO: this should happen for bitfield stores, too. Expr::EvalResult Result; @@ -12103,9 +12103,7 @@ static void CheckImplicitConversion(Sema &S, Expr *E, QualType T, return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision); } - // Only warn here if E can't possibly reach the target range, not only if - // it's not likely to be in that range. - if (TargetRange.Width > MaxSourceRange.Width) { + if (TargetRange.Width > SourceTypeRange.Width) { if (auto *UO = dyn_cast<UnaryOperator>(E)) if (UO->getOpcode() == UO_Minus) if (Source->isUnsignedIntegerType()) { @@ -12118,8 +12116,9 @@ static void CheckImplicitConversion(Sema &S, Expr *E, QualType T, } } - if (TargetRange.Width == MinSourceRange.Width && !TargetRange.NonNegative && - MinSourceRange.NonNegative && Source->isSignedIntegerType()) { + if (TargetRange.Width == LikelySourceRange.Width && + !TargetRange.NonNegative && LikelySourceRange.NonNegative && + Source->isSignedIntegerType()) { // Warn when doing a signed to signed conversion, warn if the positive // source value is exactly the width of the target type, which will // cause a negative value to be stored. @@ -12144,9 +12143,9 @@ static void CheckImplicitConversion(Sema &S, Expr *E, QualType T, // Fall through for non-constants to give a sign conversion warning. } - if ((TargetRange.NonNegative && !MinSourceRange.NonNegative) || - (!TargetRange.NonNegative && MinSourceRange.NonNegative && - MinSourceRange.Width == TargetRange.Width)) { + if ((TargetRange.NonNegative && !LikelySourceRange.NonNegative) || + (!TargetRange.NonNegative && LikelySourceRange.NonNegative && + LikelySourceRange.Width == TargetRange.Width)) { if (S.SourceMgr.isInSystemMacro(CC)) return; diff --git a/clang/test/Sema/unary-minus-integer-impcast.c b/clang/test/Sema/unary-minus-integer-impcast.c index 0eb440175881..894ceff9a40f 100644 --- a/clang/test/Sema/unary-minus-integer-impcast.c +++ b/clang/test/Sema/unary-minus-integer-impcast.c @@ -17,4 +17,7 @@ void test(void) { #else // expected-warning@-4 {{implicit conversion changes signedness: 'unsigned int' to 'long'}} #endif + + unsigned m; + int n = -(m & 0xff); // no warning } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
