For PR17164: split -fno-lax-vector-conversion into three different

levels:

 -- none: no lax vector conversions [new GCC default]
 -- integer: only conversions between integer vectors [old GCC default]
 -- all: all conversions between same-size vectors [Clang default]

For now, Clang still defaults to "all" mode, but per my proposal on
cfe-dev (2019-04-10) the default will be changed to "integer" as soon as
that doesn't break lots of testcases. (Eventually I'd like to change the
default to "none" to match GCC and general sanity.)

Following GCC's behavior, the driver flag -flax-vector-conversions is
translated to -flax-vector-conversions=integer.

llvm-svn: 371805

3 files changed, 35 insertions, 9 deletions

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 6aff423bd18..c39c1c7e3cf 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -4678,15 +4678,11 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   if (TC.SupportsProfiling())
     Args.AddLastArg(CmdArgs, options::OPT_mfentry);
 
-  // -flax-vector-conversions is default.
-  if (!Args.hasFlag(options::OPT_flax_vector_conversions,
-                    options::OPT_fno_lax_vector_conversions))
-    CmdArgs.push_back("-fno-lax-vector-conversions");
-
   if (Args.getLastArg(options::OPT_fapple_kext) ||
       (Args.hasArg(options::OPT_mkernel) && types::isCXX(InputType)))
     CmdArgs.push_back("-fapple-kext");
 
+  Args.AddLastArg(CmdArgs, options::OPT_flax_vector_conversions_EQ);
   Args.AddLastArg(CmdArgs, options::OPT_fobjc_sender_dependent_dispatch);
   Args.AddLastArg(CmdArgs, options::OPT_fdiagnostics_print_source_range_info);
   Args.AddLastArg(CmdArgs, options::OPT_fdiagnostics_parseable_fixits);
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 3db0b8827ad..0e29e6d9d4d 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2265,7 +2265,7 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
   if (Opts.OpenCL) {
     Opts.AltiVec = 0;
     Opts.ZVector = 0;
-    Opts.LaxVectorConversions = 0;
+    Opts.setLaxVectorConversions(LangOptions::LaxVectorConversionKind::None);
     Opts.setDefaultFPContractMode(LangOptions::FPC_On);
     Opts.NativeHalfType = 1;
     Opts.NativeHalfArgsAndReturns = 1;
@@ -2667,8 +2667,18 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   Opts.WritableStrings = Args.hasArg(OPT_fwritable_strings);
   Opts.ConstStrings = Args.hasFlag(OPT_fconst_strings, OPT_fno_const_strings,
                                    Opts.ConstStrings);
-  if (Args.hasArg(OPT_fno_lax_vector_conversions))
-    Opts.LaxVectorConversions = 0;
+  if (Arg *A = Args.getLastArg(OPT_flax_vector_conversions_EQ)) {
+    using LaxKind = LangOptions::LaxVectorConversionKind;
+    if (auto Kind = llvm::StringSwitch<Optional<LaxKind>>(A->getValue())
+                        .Case("none", LaxKind::None)
+                        .Case("integer", LaxKind::Integer)
+                        .Case("all", LaxKind::All)
+                        .Default(llvm::None))
+      Opts.setLaxVectorConversions(*Kind);
+    else
+      Diags.Report(diag::err_drv_invalid_value)
+          << A->getAsString(Args) << A->getValue();
+  }
   if (Args.hasArg(OPT_fno_threadsafe_statics))
     Opts.ThreadsafeStatics = 0;
   Opts.Exceptions = Args.hasArg(OPT_fexceptions);
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 849298433ac..84520052c61 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -6498,8 +6498,28 @@ bool Sema::areLaxCompatibleVectorTypes(QualType srcTy, QualType destTy) {
 bool Sema::isLaxVectorConversion(QualType srcTy, QualType destTy) {
   assert(destTy->isVectorType() || srcTy->isVectorType());
 
-  if (!Context.getLangOpts().LaxVectorConversions)
+  switch (Context.getLangOpts().getLaxVectorConversions()) {
+  case LangOptions::LaxVectorConversionKind::None:
     return false;
+
+  case LangOptions::LaxVectorConversionKind::Integer:
+    if (!srcTy->isIntegralOrEnumerationType()) {
+      auto *Vec = srcTy->getAs<VectorType>();
+      if (!Vec || !Vec->getElementType()->isIntegralOrEnumerationType())
+        return false;
+    }
+    if (!destTy->isIntegralOrEnumerationType()) {
+      auto *Vec = destTy->getAs<VectorType>();
+      if (!Vec || !Vec->getElementType()->isIntegralOrEnumerationType())
+        return false;
+    }
+    // OK, integer (vector) -> integer (vector) bitcast.
+    break;
+
+    case LangOptions::LaxVectorConversionKind::All:
+    break;
+  }
+
   return areLaxCompatibleVectorTypes(srcTy, destTy);
 }