Date: Fri, 15 Apr 2011 18:40:19 +0200 From: Dimitry Andric <dim@FreeBSD.org> To: Alexander Best <arundel@freebsd.org> Cc: freebsd-toolchain@freebsd.org, cfe-commits@cs.uiuc.edu Subject: Re: clang and 3dnow(a) Message-ID: <4DA874F3.9050101@FreeBSD.org> In-Reply-To: <20110414234106.GA22718@freebsd.org> References: <20110414234106.GA22718@freebsd.org>
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On 2011-04-15 01:41, Alexander Best wrote:
> per coincidence i discovered the following contrary behavior between gcc and
> clang:
>
> -mno-mmx implies -mno-3dnow under gcc. under clang -mno-mmx will *not* imply
> -mno-3dnow!
>
> is this a clang design feature or a bug? fixing it would be trivial (see
> attached patch).
I don't think it was intentionally designed, nor that it is a bug. It
it just arbitrary what you disable when you specify '-mno-mmx'.
However, it would probably be nice if clang emulated gcc's behaviour
here.
Adding cfe-commits@ in the loop, to see if the clang guys think this is
desirable.
diff --git a/contrib/llvm/tools/clang/lib/Basic/Targets.cpp b/contrib/llvm/tools/clang/lib/Basic/Targets.cpp
index 55321f2..1af7c52 100644
--- a/contrib/llvm/tools/clang/lib/Basic/Targets.cpp
+++ b/contrib/llvm/tools/clang/lib/Basic/Targets.cpp
@@ -1133,8 +1133,9 @@ bool X86TargetInfo::setFeatureEnabled(llvm::StringMap<bool> &Features,
Features["avx"] = true;
} else {
if (Name == "mmx")
- Features["mmx"] = Features["sse"] = Features["sse2"] = Features["sse3"] =
- Features["ssse3"] = Features["sse41"] = Features["sse42"] = false;
+ Features["mmx"] = Features["3dnow"] = Features["3dnowa"] =
+ Features["sse"] = Features["sse2"] = Features["sse3"] =
+ Features["ssse3"] = Features["sse41"] = Features["sse42"] = false;
else if (Name == "sse")
Features["sse"] = Features["sse2"] = Features["sse3"] =
Features["ssse3"] = Features["sse41"] = Features["sse42"] = false;
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