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[CodeGen] Add DebugCounter support for machine-cse #166367

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[CodeGen] Add DebugCounter support for machine-cse #166367

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9 changes: 9 additions & 0 deletions llvm/lib/CodeGen/MachineCSE.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,7 @@
#include "llvm/Pass.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/DebugCounter.h"
#include "llvm/Support/RecyclingAllocator.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
Expand All @@ -60,6 +61,9 @@ STATISTIC(NumCrossBBCSEs,
"Number of cross-MBB physreg referencing CS eliminated");
STATISTIC(NumCommutes, "Number of copies coalesced after commuting");

DEBUG_COUNTER(MachineCSECounter, "machine-cse",
"Controls which instructions are removed");

// Threshold to avoid excessive cost to compute isProfitableToCSE.
static cl::opt<int>
CSUsesThreshold("csuses-threshold", cl::Hidden, cl::init(1024),
Expand Down Expand Up @@ -668,6 +672,11 @@ bool MachineCSEImpl::ProcessBlockCSE(MachineBasicBlock *MBB) {
--NumDefs;
}

if (DoCSE && !DebugCounter::shouldExecute(MachineCSECounter)) {
LLVM_DEBUG(dbgs() << "Skip CSE due to debug counter\n");
DoCSE = false;
}

// Actually perform the elimination.
if (DoCSE) {
for (const std::pair<Register, Register> &CSEPair : CSEPairs) {
Expand Down
20 changes: 20 additions & 0 deletions llvm/test/CodeGen/AArch64/debugcounter-machine-cse.mir
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Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
# RUN: llc -mtriple=aarch64 -run-pass=machine-cse -debug-counter=machine-cse=0-1 -o - %s | FileCheck %s

---
name: debug_counter_machine_cse
body: |
bb.0:
; CHECK-LABEL: name: debug_counter_machine_cse
; CHECK: %0:gpr32 = MOVi32imm 1
; CHECK-NEXT: %1:gpr32 = ADDWrr %0, %0
; CHECK-NEXT: %4:gpr32 = ADDWrr %0, %0
; CHECK-NEXT: $w0 = COPY %4
; CHECK-NEXT: RET_ReallyLR implicit $w0
%0:gpr32 = MOVi32imm 1
%1:gpr32 = ADDWrr %0, %0
%2:gpr32 = ADDWrr %0, %0
%3:gpr32 = ADDWrr %0, %0
%4:gpr32 = ADDWrr %0, %0
$w0 = COPY %4
RET_ReallyLR implicit $w0
...