[cfe-commits] r52914 - in /cfe/trunk: include/clang/AST/ASTContext.h include/clang/AST/Builtins.def include/clang/Basic/TargetInfo.h lib/AST/ASTContext.cpp lib/CodeGen/CGBuiltin.cpp lib/CodeGen/CGExprScalar.cpp lib/CodeGen/CodeGenTypes.cpp lib/Co

[Eli Friedman]

On Mon, Jun 30, 2008 at 11:32 AM, Chris Lattner <sabre at nondot.org> wrote:
> Author: lattner
> Date: Mon Jun 30 13:32:54 2008
> New Revision: 52914
>
> URL: http://llvm.org/viewvc/llvm-project?rev=52914&view=rev
> Log:
> Make a few related changes:
>
> 1) add a new ASTContext::getFloatTypeSemantics method.
> 2) Use it from SemaExpr.cpp, CodeGenTypes.cpp and other places.
> 3) Change the TargetInfo.h get*Format methods to return their
>   fltSemantics byref instead of by pointer.
> 4) Change CodeGenFunction::EmitBuiltinExpr to allow builtins which
>   sometimes expand specially and othertimes fall back to libm.
> 5) Add support for __builtin_nan("") to codegen, cases that don't pass
>   in an empty string are currently lowered to libm calls.
> 6) Fix codegen of __builtin_infl.

Okay, makes sense... it's a rather different approach from the
original patch, but it's probably better this way.  Although, why do
we need to be able to sometimes expand the libm calls?  Are we trying
to match gcc guarantees about folding, or something like that?

I guess the constant-expression eval code will eventually need to
learn how to calculate the value of anything we want to be able to
consider constant, like __builtin_infl and __builtin_nan.  Not really
relevant to this patch, though.

-Eli