Add new intrinsic LDC_never_inline.

LDC_never_inline is a complementary intrinsic to LDC_allow_inline.
It tells the LLVM optimizer to never inline a function. This can be
useful if inlining creates incorrect code.
A possible application is core.thread.getStackTop().

dmd2/declaration.h

@@ -930,6 +930,9 @@ struct FuncDeclaration : Declaration
     // true if overridden with the pragma(allow_inline); stmt
     bool allowInlining;
 
+    // true if set with pragma(LDC_no_inline)
+    bool neverInline;
+
     // true if has inline assembler
     bool inlineAsm;
 #endif

dmd2/func.c

@@ -103,6 +103,7 @@ FuncDeclaration::FuncDeclaration(Loc loc, Loc endloc, Identifier *id, StorageCla
     // LDC
     isArrayOp = false;
     allowInlining = false;
+    neverInline = false;
     availableExternally = true; // assume this unless proven otherwise
 
     // function types in ldc don't merge if the context parameter differs

dmd2/idgen.c

@@ -278,6 +278,7 @@ Msgtable msgtable[] =
     { "LDC_va_arg" },
     { "LDC_verbose" },
     { "LDC_allow_inline" },
+    { "LDC_never_inline" },
     { "LDC_inline_asm" },
     { "LDC_inline_ir" },
     { "LDC_fence" },

dmd2/statement.c

@@ -3175,6 +3175,10 @@ Statement *PragmaStatement::semantic(Scope *sc)
     {
         sc->func->allowInlining = true;
     }
+    else if (ident == Id::LDC_never_inline)
+    {
+        sc->func->neverInline = true;
+    }
 #endif
 #if DMDV2
     else if (ident == Id::startaddress)

gen/functions.cpp

@@ -815,6 +815,11 @@ void DtoDeclareFunction(FuncDeclaration* fdecl)
         }
     }
 
+    if (fdecl->neverInline)
+    {
+        fdecl->ir.irFunc->setNeverInline();
+    }
+
     if (fdecl->llvmInternal == LLVMglobal_crt_ctor || fdecl->llvmInternal == LLVMglobal_crt_dtor)
     {
         AppendFunctionToLLVMGlobalCtorsDtors(func, fdecl->priority, fdecl->llvmInternal == LLVMglobal_crt_ctor);