Get rid of superfluous LDC-specific TypeBasic.alignment() override

16 is LLVM's default alignment for x87 floats and x86_64 targets
(verified for Linux and macOS).

dmd/mtype.d

@@ -3273,19 +3273,6 @@ extern (C++) final class TypeBasic : Type
         return target.alignsize(this);
     }
 
-version (IN_LLVM)
-{
-    override structalign_t alignment()
-    {
-        if ( (ty == Tfloat80 || ty == Timaginary80) && (size(Loc.initial) > 8)
-             && isArchx86_64() )
-        {
-            return 16;
-        }
-        return Type.alignment();
-    }
-}
-
     override bool isintegral()
     {
         //printf("TypeBasic::isintegral('%s') x%x\n", toChars(), flags);

dmd/mtype.h

@@ -402,9 +402,6 @@ public:
     Type *syntaxCopy();
     d_uns64 size(const Loc &loc) /*const*/;
     unsigned alignsize();
-#if IN_LLVM
-    structalign_t alignment();
-#endif
     bool isintegral();
     bool isfloating() /*const*/;
     bool isreal() /*const*/;

gen/llvmhelpers.cpp

@@ -63,10 +63,6 @@ llvm::cl::opt<llvm::GlobalVariable::ThreadLocalMode> clThreadModel(
  * Simple Triple helpers for DFE
  * TODO: find better location for this
  ******************************************************************************/
-bool isArchx86_64() {
-  return global.params.targetTriple->getArch() == llvm::Triple::x86_64;
-}
-
 bool isTargetWindowsMSVC() {
   return global.params.targetTriple->isWindowsMSVCEnvironment();
 }

gen/llvmhelpers.d

@@ -19,5 +19,4 @@ import dmd.dtemplate;
 /// Fixup an overloaded intrinsic name string.
 extern (C++) void DtoSetFuncDeclIntrinsicName(TemplateInstance ti, TemplateDeclaration td, FuncDeclaration fd);
 
-extern (C++) bool isArchx86_64();
 extern (C++) bool isTargetWindowsMSVC();