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Reenable JumpTableToSwitch pass by default #83229

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Reenable JumpTableToSwitch pass by default #83229

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2 changes: 1 addition & 1 deletion llvm/lib/Passes/PassBuilderPipelines.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -247,7 +247,7 @@ static cl::opt<bool>

static cl::opt<bool> EnableJumpTableToSwitch(
"enable-jump-table-to-switch",
cl::desc("Enable JumpTableToSwitch pass (default = off)"));
cl::desc("Enable JumpTableToSwitch pass (default = on)"), cl::init(true));

// This option is used in simplifying testing SampleFDO optimizations for
// profile loading.
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10 changes: 9 additions & 1 deletion llvm/lib/Transforms/Scalar/JumpTableToSwitch.cpp
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Expand Up @@ -18,11 +18,19 @@

using namespace llvm;

// The choice of this threshold is motivated by the following data points:
// 1. Chromium successfully builds with JumpTableSizeThreshold=10, and this
// build includes many third-party C++ projects.
// 2. Flang experiences several compilation slow-down issues with
// JumpTableSizeThreshold=9, builds successfully with JumpTableSizeThreshold=8.
// On several investigated pathological examples the expansion of jump tables
// introduced more than 100K new callsites where inlining happened.
// 3. TODO: Consider increasing this value.
static cl::opt<unsigned>
JumpTableSizeThreshold("jump-table-to-switch-size-threshold", cl::Hidden,
cl::desc("Only split jump tables with size less or "
"equal than JumpTableSizeThreshold."),
cl::init(10));
cl::init(5));

// TODO: Consider adding a cost model for profitability analysis of this
// transformation. Currently we replace a jump table with a switch if all the
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6 changes: 1 addition & 5 deletions llvm/test/Other/new-pm-defaults.ll
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Expand Up @@ -71,10 +71,6 @@
; RUN: -passes='default<O3>' -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefixes=CHECK-O,CHECK-DEFAULT,CHECK-O3,%llvmcheckext,CHECK-EP-OPTIMIZER-LAST,CHECK-O23SZ

; RUN: opt -disable-verify -verify-analysis-invalidation=0 -eagerly-invalidate-analyses=0 -debug-pass-manager \
; RUN: -passes='default<O3>' -enable-jump-table-to-switch -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefixes=CHECK-O,CHECK-DEFAULT,CHECK-O3,CHECK-JUMP-TABLE-TO-SWITCH,CHECK-O23SZ,%llvmcheckext

; RUN: opt -disable-verify -verify-analysis-invalidation=0 -eagerly-invalidate-analyses=0 -debug-pass-manager \
; RUN: -passes='default<O3>' -enable-matrix -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefixes=CHECK-O,CHECK-DEFAULT,CHECK-O3,CHECK-O23SZ,%llvmcheckext,CHECK-MATRIX
Expand Down Expand Up @@ -155,7 +151,7 @@
; CHECK-O23SZ-NEXT: Running analysis: LazyValueAnalysis
; CHECK-O23SZ-NEXT: Running pass: CorrelatedValuePropagationPass
; CHECK-O23SZ-NEXT: Invalidating analysis: LazyValueAnalysis
; CHECK-JUMP-TABLE-TO-SWITCH-NEXT: Running pass: JumpTableToSwitchPass
; CHECK-O23SZ-NEXT: Running pass: JumpTableToSwitchPass
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O23SZ-NEXT: Running pass: AggressiveInstCombinePass
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1 change: 1 addition & 0 deletions llvm/test/Other/new-pm-thinlto-postlink-defaults.ll
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Expand Up @@ -90,6 +90,7 @@
; CHECK-O23SZ-NEXT: Running analysis: LazyValueAnalysis
; CHECK-O23SZ-NEXT: Running pass: CorrelatedValuePropagationPass
; CHECK-O23SZ-NEXT: Invalidating analysis: LazyValueAnalysis
; CHECK-O23SZ-NEXT: Running pass: JumpTableToSwitchPass
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O23SZ-NEXT: Running pass: AggressiveInstCombinePass
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1 change: 1 addition & 0 deletions llvm/test/Other/new-pm-thinlto-postlink-pgo-defaults.ll
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Expand Up @@ -78,6 +78,7 @@
; CHECK-O23SZ-NEXT: Running analysis: LazyValueAnalysis
; CHECK-O23SZ-NEXT: Running pass: CorrelatedValuePropagationPass
; CHECK-O23SZ-NEXT: Invalidating analysis: LazyValueAnalysis
; CHECK-O23SZ-NEXT: Running pass: JumpTableToSwitchPass
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O23SZ-NEXT: Running pass: AggressiveInstCombinePass
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1 change: 1 addition & 0 deletions llvm/test/Other/new-pm-thinlto-postlink-samplepgo-defaults.ll
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Expand Up @@ -86,6 +86,7 @@
; CHECK-O23SZ-NEXT: Running analysis: LazyValueAnalysis
; CHECK-O23SZ-NEXT: Running pass: CorrelatedValuePropagationPass
; CHECK-O23SZ-NEXT: Invalidating analysis: LazyValueAnalysis
; CHECK-O23SZ-NEXT: Running pass: JumpTableToSwitchPass
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O23SZ-NEXT: Running pass: AggressiveInstCombinePass
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1 change: 1 addition & 0 deletions llvm/test/Other/new-pm-thinlto-prelink-defaults.ll
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Expand Up @@ -121,6 +121,7 @@
; CHECK-O23SZ-NEXT: Running analysis: LazyValueAnalysis
; CHECK-O23SZ-NEXT: Running pass: CorrelatedValuePropagationPass
; CHECK-O23SZ-NEXT: Invalidating analysis: LazyValueAnalysis
; CHECK-O23SZ-NEXT: Running pass: JumpTableToSwitchPass
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O23SZ-NEXT: Running pass: AggressiveInstCombinePass
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1 change: 1 addition & 0 deletions llvm/test/Other/new-pm-thinlto-prelink-pgo-defaults.ll
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Expand Up @@ -118,6 +118,7 @@
; CHECK-O23SZ-NEXT: Running analysis: LazyValueAnalysis
; CHECK-O23SZ-NEXT: Running pass: CorrelatedValuePropagationPass
; CHECK-O23SZ-NEXT: Invalidating analysis: LazyValueAnalysis
; CHECK-O23SZ-NEXT: Running pass: JumpTableToSwitchPass
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O-NEXT: Running analysis: BlockFrequencyAnalysis on foo
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1 change: 1 addition & 0 deletions llvm/test/Other/new-pm-thinlto-prelink-samplepgo-defaults.ll
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Expand Up @@ -90,6 +90,7 @@
; CHECK-O23SZ-NEXT: Running analysis: LazyValueAnalysis
; CHECK-O23SZ-NEXT: Running pass: CorrelatedValuePropagationPass
; CHECK-O23SZ-NEXT: Invalidating analysis: LazyValueAnalysis
; CHECK-O23SZ-NEXT: Running pass: JumpTableToSwitchPass
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O23SZ-NEXT: Running pass: AggressiveInstCombinePass
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