[PATCH] [x86] Do not convert to cmp32 for Atom arch.

[Jim Grosbach]

This LGTM, but please also add a test-case.

On Feb 19, 2014, at 9:08 AM, Sergey Okunev <sergey.k.okunev at gmail.com> wrote:

> Hi grosbach,
> 
> Added 'Atom' check in 'X86TargetLowering::EmitCmp' func.
> 
> http://llvm-reviews.chandlerc.com/D2824
> 
> Files:
>  lib/Target/X86/X86ISelLowering.cpp
> 
> Index: lib/Target/X86/X86ISelLowering.cpp
> ===================================================================
> --- lib/Target/X86/X86ISelLowering.cpp
> +++ lib/Target/X86/X86ISelLowering.cpp
> @@ -9774,12 +9774,14 @@
> 
>   if ((Op0.getValueType() == MVT::i8 || Op0.getValueType() == MVT::i16 ||
>        Op0.getValueType() == MVT::i32 || Op0.getValueType() == MVT::i64)) {
> -    // Do the comparison at i32 if it's smaller. This avoids subregister
> -    // aliasing issues. Keep the smaller reference if we're optimizing for
> -    // size, however, as that'll allow better folding of memory operations.
> +    // Do the comparison at i32 if it's smaller, besides the Atom case. 
> +    // This avoids subregister aliasing issues. Keep the smaller reference 
> +    // if we're optimizing for size, however, as that'll allow better folding 
> +    // of memory operations.
>     if (Op0.getValueType() != MVT::i32 && Op0.getValueType() != MVT::i64 &&
>         !DAG.getMachineFunction().getFunction()->getAttributes().hasAttribute(
> -             AttributeSet::FunctionIndex, Attribute::MinSize)) {
> +             AttributeSet::FunctionIndex, Attribute::MinSize) &&
> +        !Subtarget->isAtom()) {
>       unsigned ExtendOp =
>           isX86CCUnsigned(X86CC) ? ISD::ZERO_EXTEND : ISD::SIGN_EXTEND;
>       Op0 = DAG.getNode(ExtendOp, dl, MVT::i32, Op0);
> <D2824.1.patch>