Merge commit '88f04bdbd861' from llvm.org/main into experimental/cas/main

Author: git apple-llvm automerger

clang/docs/ReleaseNotes.rst

@@ -210,6 +210,10 @@ Improvements to Clang's diagnostics
 - ``-Wenum-conversion`` now warns on converting a signed enum of one type to an
   unsigned enum of a different type (or vice versa) rather than
   ``-Wsign-conversion``.
+- Added the ``-Wunreachable-code-generic-assoc`` diagnostic flag (grouped under
+  the ``-Wunreachable-code`` flag) which is enabled by default and warns the
+  user about ``_Generic`` selection associations which are unreachable because
+  the type specified is an array type or a qualified type.
 
 Non-comprehensive list of changes in this release
 -------------------------------------------------

clang/include/clang/Basic/DiagnosticGroups.td

@@ -843,9 +843,11 @@ def ReservedIdentifier : DiagGroup<"reserved-identifier",
 //
 def UnreachableCodeLoopIncrement : DiagGroup<"unreachable-code-loop-increment">;
 def UnreachableCodeFallthrough : DiagGroup<"unreachable-code-fallthrough">;
+def UnreachableCodeGenericAssoc : DiagGroup<"unreachable-code-generic-assoc">;
 def UnreachableCode : DiagGroup<"unreachable-code",
                                 [UnreachableCodeLoopIncrement,
-                                 UnreachableCodeFallthrough]>;
+                                 UnreachableCodeFallthrough,
+                                 UnreachableCodeGenericAssoc]>;
 def UnreachableCodeBreak : DiagGroup<"unreachable-code-break">;
 def UnreachableCodeReturn : DiagGroup<"unreachable-code-return">;
 def UnreachableCodeAggressive : DiagGroup<"unreachable-code-aggressive",

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -693,6 +693,10 @@ def warn_unreachable_fallthrough_attr : Warning<
   InGroup<UnreachableCodeFallthrough>, DefaultIgnore;
 def note_unreachable_silence : Note<
   "silence by adding parentheses to mark code as explicitly dead">;
+def warn_unreachable_association : Warning<
+  "due to lvalue conversion of the controlling expression, association of type "
+  "%0 will never be selected because it is %select{of array type|qualified}1">,
+  InGroup<UnreachableCodeGenericAssoc>;
 
 /// Built-in functions.
 def ext_implicit_lib_function_decl : ExtWarn<

clang/include/clang/Frontend/Utils.h

@@ -206,7 +206,7 @@ struct CreateInvocationOptions {
   /// This is used to replace -include with -include-pch in the cc1 args.
   /// FIXME: ProbePrecompiled=true is a poor, historical default.
   /// It misbehaves if the PCH file is from GCC, has the wrong version, etc.
-  bool ProbePrecompiled = true;
+  bool ProbePrecompiled = false;
   /// If set, the target is populated with the cc1 args produced by the driver.
   /// This may be populated even if createInvocation returns nullptr.
   std::vector<std::string> *CC1Args = nullptr;

clang/lib/CodeGen/CGExprCXX.cpp

@@ -1573,7 +1573,7 @@ llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) {
   llvm::Value *allocSize =
     EmitCXXNewAllocSize(*this, E, minElements, numElements,
                         allocSizeWithoutCookie);
-  CharUnits allocAlign = getContext().getPreferredTypeAlignInChars(allocType);
+  CharUnits allocAlign = getContext().getTypeAlignInChars(allocType);
 
   // Emit the allocation call.  If the allocator is a global placement
   // operator, just "inline" it directly.

clang/lib/Frontend/ASTUnit.cpp

@@ -1732,6 +1732,7 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
     CreateInvocationOptions CIOpts;
     CIOpts.VFS = VFS;
     CIOpts.Diags = Diags;
+    CIOpts.ProbePrecompiled = true; // FIXME: historical default. Needed?
     CI = createInvocation(llvm::makeArrayRef(ArgBegin, ArgEnd),
                           std::move(CIOpts));
     if (!CI)

clang/lib/Sema/SemaExpr.cpp

@@ -1685,6 +1685,25 @@ Sema::CreateGenericSelectionExpr(SourceLocation KeyLoc,
           D = diag::err_assoc_type_nonobject;
         else if (Types[i]->getType()->isVariablyModifiedType())
           D = diag::err_assoc_type_variably_modified;
+        else {
+          // Because the controlling expression undergoes lvalue conversion,
+          // array conversion, and function conversion, an association which is
+          // of array type, function type, or is qualified can never be
+          // reached. We will warn about this so users are less surprised by
+          // the unreachable association. However, we don't have to handle
+          // function types; that's not an object type, so it's handled above.
+          unsigned Reason = 0;
+          QualType QT = Types[i]->getType();
+          if (QT->isArrayType())
+            Reason = 1;
+          else if (QT.hasQualifiers())
+            Reason = 2;
+
+          if (Reason)
+            Diag(Types[i]->getTypeLoc().getBeginLoc(),
+                 diag::warn_unreachable_association)
+                << QT << (Reason - 1);
+        }
 
         if (D != 0) {
           Diag(Types[i]->getTypeLoc().getBeginLoc(), D)

clang/test/CodeGen/aarch64-sve2-intrinsics/acle_sve2_aba.c

@@ -5,8 +5,6 @@
 // RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +sve2 -fallow-half-arguments-and-returns -S -O1 -Werror -Wall -emit-llvm -o - -x c++ %s | FileCheck %s -check-prefix=CPP-CHECK
 // RUN: %clang_cc1 -DSVE_OVERLOADED_FORMS -triple aarch64-none-linux-gnu -target-feature +sve2 -fallow-half-arguments-and-returns -S -O1 -Werror -Wall -emit-llvm -o - %s | FileCheck %s
 // RUN: %clang_cc1 -DSVE_OVERLOADED_FORMS -triple aarch64-none-linux-gnu -target-feature +sve2 -fallow-half-arguments-and-returns -S -O1 -Werror -Wall -emit-llvm -o - -x c++ %s | FileCheck %s -check-prefix=CPP-CHECK
-// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +sve -fallow-half-arguments-and-returns -fsyntax-only -Wno-error=implicit-function-declaration -verify -verify-ignore-unexpected=error %s
-// RUN: %clang_cc1 -DSVE_OVERLOADED_FORMS -triple aarch64-none-linux-gnu -target-feature +sve -fallow-half-arguments-and-returns -fsyntax-only -Wno-error=implicit-function-declaration -verify=overload -verify-ignore-unexpected=error %s
 
 #include <arm_sve.h>
 
@@ -29,8 +27,6 @@
 //
 svint8_t test_svaba_s8(svint8_t op1, svint8_t op2, svint8_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_s8'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_s8,,)(op1, op2, op3);
 }
 
@@ -46,8 +42,6 @@ svint8_t test_svaba_s8(svint8_t op1, svint8_t op2, svint8_t op3)
 //
 svint16_t test_svaba_s16(svint16_t op1, svint16_t op2, svint16_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_s16'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_s16,,)(op1, op2, op3);
 }
 
@@ -63,8 +57,6 @@ svint16_t test_svaba_s16(svint16_t op1, svint16_t op2, svint16_t op3)
 //
 svint32_t test_svaba_s32(svint32_t op1, svint32_t op2, svint32_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_s32'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_s32,,)(op1, op2, op3);
 }
 
@@ -80,8 +72,6 @@ svint32_t test_svaba_s32(svint32_t op1, svint32_t op2, svint32_t op3)
 //
 svint64_t test_svaba_s64(svint64_t op1, svint64_t op2, svint64_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_s64'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_s64,,)(op1, op2, op3);
 }
 
@@ -97,8 +87,6 @@ svint64_t test_svaba_s64(svint64_t op1, svint64_t op2, svint64_t op3)
 //
 svuint8_t test_svaba_u8(svuint8_t op1, svuint8_t op2, svuint8_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_u8'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_u8,,)(op1, op2, op3);
 }
 
@@ -114,8 +102,6 @@ svuint8_t test_svaba_u8(svuint8_t op1, svuint8_t op2, svuint8_t op3)
 //
 svuint16_t test_svaba_u16(svuint16_t op1, svuint16_t op2, svuint16_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_u16'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_u16,,)(op1, op2, op3);
 }
 
@@ -131,8 +117,6 @@ svuint16_t test_svaba_u16(svuint16_t op1, svuint16_t op2, svuint16_t op3)
 //
 svuint32_t test_svaba_u32(svuint32_t op1, svuint32_t op2, svuint32_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_u32'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_u32,,)(op1, op2, op3);
 }
 
@@ -148,8 +132,6 @@ svuint32_t test_svaba_u32(svuint32_t op1, svuint32_t op2, svuint32_t op3)
 //
 svuint64_t test_svaba_u64(svuint64_t op1, svuint64_t op2, svuint64_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_u64'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_u64,,)(op1, op2, op3);
 }
 
@@ -169,8 +151,6 @@ svuint64_t test_svaba_u64(svuint64_t op1, svuint64_t op2, svuint64_t op3)
 //
 svint8_t test_svaba_n_s8(svint8_t op1, svint8_t op2, int8_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_n_s8'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_n_s8,,)(op1, op2, op3);
 }
 
@@ -190,8 +170,6 @@ svint8_t test_svaba_n_s8(svint8_t op1, svint8_t op2, int8_t op3)
 //
 svint16_t test_svaba_n_s16(svint16_t op1, svint16_t op2, int16_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_n_s16'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_n_s16,,)(op1, op2, op3);
 }
 
@@ -211,8 +189,6 @@ svint16_t test_svaba_n_s16(svint16_t op1, svint16_t op2, int16_t op3)
 //
 svint32_t test_svaba_n_s32(svint32_t op1, svint32_t op2, int32_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_n_s32'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_n_s32,,)(op1, op2, op3);
 }
 
@@ -232,8 +208,6 @@ svint32_t test_svaba_n_s32(svint32_t op1, svint32_t op2, int32_t op3)
 //
 svint64_t test_svaba_n_s64(svint64_t op1, svint64_t op2, int64_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_n_s64'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_n_s64,,)(op1, op2, op3);
 }
 
@@ -253,8 +227,6 @@ svint64_t test_svaba_n_s64(svint64_t op1, svint64_t op2, int64_t op3)
 //
 svuint8_t test_svaba_n_u8(svuint8_t op1, svuint8_t op2, uint8_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_n_u8'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_n_u8,,)(op1, op2, op3);
 }
 
@@ -274,8 +246,6 @@ svuint8_t test_svaba_n_u8(svuint8_t op1, svuint8_t op2, uint8_t op3)
 //
 svuint16_t test_svaba_n_u16(svuint16_t op1, svuint16_t op2, uint16_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_n_u16'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_n_u16,,)(op1, op2, op3);
 }
 
@@ -295,8 +265,6 @@ svuint16_t test_svaba_n_u16(svuint16_t op1, svuint16_t op2, uint16_t op3)
 //
 svuint32_t test_svaba_n_u32(svuint32_t op1, svuint32_t op2, uint32_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_n_u32'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_n_u32,,)(op1, op2, op3);
 }
 
@@ -316,7 +284,5 @@ svuint32_t test_svaba_n_u32(svuint32_t op1, svuint32_t op2, uint32_t op3)
 //
 svuint64_t test_svaba_n_u64(svuint64_t op1, svuint64_t op2, uint64_t op3)
 {
-  // overload-warning@+2 {{call to undeclared function 'svaba'; ISO C99 and later do not support implicit function declarations}}
-  // expected-warning@+1 {{call to undeclared function 'svaba_n_u64'; ISO C99 and later do not support implicit function declarations}}
   return SVE_ACLE_FUNC(svaba,_n_u64,,)(op1, op2, op3);
 }