Bug 39151 – Incorrect codegen for slowcase of < in 64-bit

• Component: New Bugs
• Status: RESOLVED FIXED

[Oliver Hunt]

Incorrect codegen for slowcase of < in 64-bit

[Oliver Hunt]

Created attachment 56144 [details]
Patch

[Mark Rowe (bdash)]

Comment on attachment 56144 [details]
Patch

> diff --git a/JavaScriptCore/ChangeLog b/JavaScriptCore/ChangeLog
> index 7ac6b3cb96d0c4ac0fb61816a54298b1f9641159..5dea41a05bd293fddb0671ffcec381b4dcea6a35 100644
> --- a/JavaScriptCore/ChangeLog
> +++ b/JavaScriptCore/ChangeLog
> @@ -1,3 +1,16 @@
> [phone]  Oliver Hunt  <[e-mail]>
> +
> +        Reviewed by NOBODY (OOPS!).
> +
> +        Incorrect codegen for slowcase of < in 64-bit
> +        https://bugs.webkit.org/show_bug.cgi?id=39151
> +
> +        Call the correct stud for the slowcases of the < operator.

“stud”

> diff --git a/JavaScriptCore/jit/JITArithmetic.cpp b/JavaScriptCore/jit/JITArithmetic.cpp
> index e5a4620d8ba24162b9db52d39421267f71d6bebc..cd39b3ad01c1ff45e15551efbbe01f0c12b633fc 100644
> --- a/JavaScriptCore/jit/JITArithmetic.cpp
> +++ b/JavaScriptCore/jit/JITArithmetic.cpp
> @@ -370,7 +370,7 @@ void JIT::emitSlow_op_jnless(Instruction* currentInstruction, Vector<SlowCaseEnt
>          linkSlowCase(iter);
>          linkSlowCase(iter);
>          linkSlowCase(iter);
> -        JITStubCall stubCall(this, cti_op_jlesseq);
> +        JITStubCall stubCall(this, cti_op_jless);
>          stubCall.addArgument(op1, regT0);
>          stubCall.addArgument(op2, regT1);
>          stubCall.call();

Is it really correct for emitSlow_op_jnless to call cti_op_jless?  I’d have expected it to call cti_op_jnless.

[Maciej Stachowiak]

(In reply to comment #2)

> 
> Is it really correct for emitSlow_op_jnless to call cti_op_jless?  I’d have expected it to call cti_op_jnless.

Yes, it's correct, there is no cti_op_jnless. The following branch reverses the sense of the comparison.

[Maciej Stachowiak]

Comment on attachment 56144 [details]
Patch

JavaScriptCore/ChangeLog:8
 +          Call the correct stud for the slowcases of the < operator.
Typo as already noted by Mark.

r=me if you fix that.

[Oliver Hunt]

Committed r59547: <http://trac.webkit.org/changeset/59547>