JIT: Invalidate loop table after unrolling and dominators after MarkLocalVars #95854
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Null out the loop table as part of setting optLoopTableValid = false. This reveals a few cases where we were using it even after invalidation. A few diffs expected from the fgCanCompactBlocks change because we now compact some loop headers.
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Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch Issue DetailsNull out the loop table as part of setting optLoopTableValid = false. This reveals a few cases where we were using it even after invalidation. A few diffs expected from the
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| if (m_comp->optLoopTableValid) | ||
| { | ||
| m_comp->fgUpdateLoopsAfterCompacting(m_b1, m_b3); | ||
| m_comp->fgUpdateLoopsAfterCompacting(m_b1, m_b2); | ||
| if (optReturnBlock) | ||
| { | ||
| m_comp->fgUpdateLoopsAfterCompacting(m_b1, m_b3); | ||
| } |
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Some of these checks are always false, like in this case... I'll remove them all as part of the big code deletion in the future.
jakobbotsch
changed the title
| DoPhase(this, PHASE_MARK_LOCAL_VARS, &Compiler::lvaMarkLocalVars); | ||
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| // Dominator and reachability sets are no longer valid. | ||
| fgDomsComputed = false; | ||
| fgCompactRenumberQuirk = true; | ||
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lvaMarkLocalVars uses Compiler::IsDominatedByExceptionalEntry to set LclVarDsc::lvVolatileHint. That is used by VN-based copy prop as part of the heuristic. My next step will be to compute SSA's dominators after unrolling above and then use those dominators to compute this heuristic instead. That will allow us to move fgDomsComputed up to where the loop table is invalidated as well.
| else | ||
| { | ||
| // TODO-Quirk: Remove | ||
| JITDUMP("Renumbering " FMT_BB " to be " FMT_BB " for a quirk\n", block->bbNum, bNext->bbNum); | ||
| } |
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This quirk has surprisingly large diffs.
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@BruceForstall feel free to take a look at this one if you have time once the diffs are done. I need some extra work for |
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cc @dotnet/jit-contrib PTAL @BruceForstall Surprisingly large TP wins with the win-x64 host compiler, but seems to be some MSVC related oddity since the other targets don't see the same. The detailed diff shows that it is from the Base: 151246609045, Diff: 150947499733, -0.1978%
79307193 : +6.15% : 16.62% : +0.0524% : public: bool __cdecl Compiler::fgUpdateFlowGraph(bool, bool)
6316694 : +173.37% : 1.32% : +0.0042% : public: void __cdecl Compiler::optFindNewLoops(void)
1122411 : +0.49% : 0.24% : +0.0007% : public: void __cdecl Compiler::compInit(class ArenaAllocator *, struct CORINFO_METHOD_STRUCT_*, class ICorJitInfo *, struct CORINFO_METHOD_INFO *, struct InlineInfo *)
635604 : +0.39% : 0.13% : +0.0004% : public: void __cdecl Compiler::fgCompactBlocks(struct BasicBlock *, struct BasicBlock *)
614159 : +0.07% : 0.13% : +0.0004% : public: void __cdecl Compiler::fgPerBlockLocalVarLiveness(void)
-751605 : -100.00% : 0.16% : -0.0005% : public: enum PhaseStatus __cdecl Compiler::optClearLoopIterInfo(void)
-1193033 : -2.48% : 0.25% : -0.0008% : public: class BasicBlock::BBSuccList __cdecl BasicBlock::Succs(void) const
-2454913 : -0.68% : 0.51% : -0.0016% : void __cdecl DoPhase(class Compiler *, enum Phases, enum PhaseStatus (__cdecl Compiler::*)(void))
-2580058 : -2.82% : 0.54% : -0.0017% : public: bool __cdecl Compiler::fgExpandRarelyRunBlocks(void)
-4782745 : -56.62% : 1.00% : -0.0032% : protected: void __cdecl Compiler::optUpdateLoopsBeforeRemoveBlock(struct BasicBlock *, bool)
-5065556 : -0.33% : 1.06% : -0.0033% : memset
-10648527 : -22.10% : 2.23% : -0.0070% : public: bool __cdecl Compiler::optJumpThreadPhi(struct BasicBlock *const, struct GenTree *, unsigned int)
-14403526 : -9.11% : 3.02% : -0.0095% : public: enum Compiler::FoldResult __cdecl Compiler::fgFoldConditional(struct BasicBlock *)
-18271428 : -100.00% : 3.83% : -0.0121% : public: void __cdecl Compiler::fgUpdateLoopsAfterCompacting(struct BasicBlock *, struct BasicBlock *)
-326814374 : -89.09% : 68.47% : -0.2161% : public: bool __cdecl Compiler::fgCanCompactBlocks(struct BasicBlock *, struct BasicBlock *) |
Invalidate the loop table right after unrolling. Invalidate dominators right after MarkLocalVars.
Diffs come from two sources:
optUnmarkLoopBlocksthat would unscale the loop blocksAs always there are also quirks that I'll remove separately.