[llvm] 2461cdb - [CodeGen][SimplifyCFG] Teach DwarfEHPrepare to preserve DomTree

[Martin Storsjö via llvm-commits]

On Fri, 1 Jan 2021, Roman Lebedev via llvm-commits wrote:

>
> Author: Roman Lebedev
> Date: 2021-01-02T01:01:19+03:00
> New Revision: 2461cdb41724298591133c811df82b0064adfa6b
>
> URL: https://github.com/llvm/llvm-project/commit/2461cdb41724298591133c811df82b0064adfa6b
> DIFF: https://github.com/llvm/llvm-project/commit/2461cdb41724298591133c811df82b0064adfa6b.diff
>
> LOG: [CodeGen][SimplifyCFG] Teach DwarfEHPrepare to preserve DomTree

Hi,

This caused a notable compile time performance regression. With 
https://martin.st/temp/libyuv-preproc.cpp compiled with "clang -target 
x86_64-w64-mingw32 -w -c -O2", the compile time went from around 75 
seconds to 145 seconds, almost doubling it.

// Martin