[PATCH] ARMv8 IfConversion must skip narrow instructions that a) define CPSR and b) wouldn't affect CPSR in an IT block

[Artyom Skrobov]

Tim, thanks for taking a look!

No, it doesn't really apply, because in v7 the SizeReduction step doesn't run until after the IfConversion, therefore IfConversion in v7 cannot encounter these narrow Thumb instructions.


-----Original Message-----
From: Tim Northover [mailto:t.p.northover at gmail.com]
Sent: 25 February 2014 16:38
To: Artyom Skrobov
Cc: llvm-commits; Weiming Zhao
Subject: Re: [PATCH] ARMv8 IfConversion must skip narrow instructions that a) define CPSR and b) wouldn't affect CPSR in an IT block

Hi Artyom,

> Therefore, when IfConversion applies the new ARMv8 restrictions, it must not
> embed such an instruction into an IT block *whenever CPSR is live after the
> instruction*.

Doesn't this apply on v7 as well? If so, that v8 function is the wrong
place to apply the fix.

Cheers.

Tim.


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