Delete lvVerTypeInfo

[SingleAccretion]

Saves 0.7% in memory consumption when CG-ing CoreLib.

We're mostly not expecting diffs, except a few where the new "is normed" logic in fgFindJumpTargets leads to us to inline something we didn't before. The reason this happens is that previously we would assign "is normed" false in case the inlining info had TI_ERROR (invalid) lclVerTypeInfos in it.

Diffs - there is a large TP regression on x86.

I have built a PIN-based mini-profiler to diagnose it, here's is an example of a diff it produces for a method context representative of the regression: PIN diff. It took me some time to realize this, but the cause is rather prosaic: LclVarDsc goes from 88 to 80 bytes and this causes MSVC to use lea + shl instead of imul for pointer arithmetic fetching LclVarDsc*s, inflating the retired instructions count. Evidently, this also pessimizes MSVC's inliner sometimes, but I am not too worried about that given we have native PGO.

To confirm, I added this "useless" padding to LclVarDsc:

    unsigned lvSlotNum; // original slot # (if remapped)

+   unsigned pad1;
+   unsigned pad2;

And the regression went away.

[ghost]

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Issue Details

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Saves 0.7% in memory consumption when CG-ing CoreLib.

We're mostly not expecting diffs, except a few (< 10 cases across all of SPMI) where the new "is normed" logic in fgFindJumpTargets leads to us to inline something we didn't before. The reason this happens is that previously we would assign "is normed" false in case the inlining info had TI_ERROR (invalid) lclVerTypeInfos in it.

Author:	SingleAccretion
Assignees:	-
Labels:	area-CodeGen-coreclr, community-contribution
Milestone:	-

[SingleAccretion]

@dotnet/jit-contrib

[AndyAyersMS]

Thanks for the cleanup.

[jakobbotsch]

I have built a PIN-based mini-profiler to diagnose it, here's is an example of a diff it produces for a method context representative of the regression: PIN diff

This was really cool btw, may I suggest you make it available? :-)

[SingleAccretion]

may I suggest you make it available? :-)

Sure, it is a very simplistic single-threaded tool: https://gist.github.com/SingleAccretion/322071577c481040e409b98b6e936adf.