[PATCH] D43542: [CodeGen][FastRegAlloc] Disable registers spilling for a naked function (PR28641)

[Konstantin Belochapka via Phabricator via llvm-commits]

kbelochapka added a comment.

Hi Quentin,
The dead flag on those registers is not set because we do not run "Live Variable Analysis" pass on -O0 optimization level.
We can add Live Variable Analysis pass prior of execution of Fast Register Allocator pass, but this will cause ~59 LIT tests to fail.
At the same time, in some situations the produced assembler code is more clean, does not contain unnecessary register spills.
And I am not sure can this potentially affect a code debuggability or not. 
What would be your suggestion? Shall we add Live Variable Analysis pass on -O0?


https://reviews.llvm.org/D43542