llvm-reduce: Add volatile reduction pass

Removing volatile may help optimization passes do more to the IR. However,
this will increase scheduler freedom.
This commit is contained in:
Matt Arsenault 2022-10-21 14:03:51 -07:00 committed by Matt Arsenault
parent 27902eea0f
commit 596fdf75d9
5 changed files with 200 additions and 0 deletions

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@ -0,0 +1,135 @@
; RUN: llvm-reduce --abort-on-invalid-reduction --delta-passes=volatile --test FileCheck --test-arg --check-prefixes=INTERESTING,CHECK --test-arg %s --test-arg --input-file %s -o %t
; RUN: FileCheck -check-prefixes=RESULT,CHECK %s < %t
; CHECK-LABEL: @load_volatile_keep(
; INTERESTING: load volatile
; RESULT: %op = load volatile i32,
define i32 @load_volatile_keep(ptr %ptr) {
%op = load volatile i32, ptr %ptr
ret i32 %op
}
; CHECK-LABEL: @load_volatile_drop(
; INTERESTING: load
; RESULT: %op = load i32,
define i32 @load_volatile_drop(ptr %ptr) {
%op = load volatile i32, ptr %ptr
ret i32 %op
}
; CHECK-LABEL: @store_volatile_keep(
; INTERESTING: store volatile
; RESULT: store volatile i32 0,
define void @store_volatile_keep(ptr %ptr) {
store volatile i32 0, ptr %ptr
ret void
}
; CHECK-LABEL: @store_volatile_drop(
; INTERESTING: store
; RESULT: store i32 0,
define void @store_volatile_drop(ptr %ptr) {
store volatile i32 0, ptr %ptr
ret void
}
; CHECK-LABEL: @atomicrmw_volatile_keep(
; INTERESTING: atomicrmw volatile
; RESULT: atomicrmw volatile add ptr %ptr
define i32 @atomicrmw_volatile_keep(ptr %ptr) {
%val = atomicrmw volatile add ptr %ptr, i32 3 seq_cst
ret i32 %val
}
; CHECK-LABEL: @atomicrmw_volatile_drop(
; INTERESTING: atomicrmw
; RESULT: atomicrmw add ptr %ptr
define i32 @atomicrmw_volatile_drop(ptr %ptr) {
%val = atomicrmw volatile add ptr %ptr, i32 3 seq_cst
ret i32 %val
}
; CHECK-LABEL: @cmpxchg_volatile_keep(
; INTERESTING: cmpxchg volatile
; RESULT: cmpxchg volatile ptr %ptr, i32 %old, i32 %in seq_cst seq_cst
define { i32, i1 } @cmpxchg_volatile_keep(ptr %ptr, i32 %old, i32 %in) {
%val = cmpxchg volatile ptr %ptr, i32 %old, i32 %in seq_cst seq_cst
ret { i32, i1 } %val
}
; CHECK-LABEL: @cmpxchg_volatile_drop(
; INTERESTING: cmpxchg
; RESULT: cmpxchg ptr %ptr, i32 %old, i32 %in seq_cst seq_cst
define { i32, i1 } @cmpxchg_volatile_drop(ptr %ptr, i32 %old, i32 %in) {
%val = cmpxchg volatile ptr %ptr, i32 %old, i32 %in seq_cst seq_cst
ret { i32, i1 } %val
}
; CHECK-LABEL: @memcpy_volatile_keep(
; INTERESTING: i1 true
; RESULT: call void @llvm.memcpy.p0.p0.i64(ptr %dst, ptr %src, i64 %size, i1 true)
define void @memcpy_volatile_keep(ptr %dst, ptr %src, i64 %size) {
call void @llvm.memcpy.p0.p0.i64(ptr %dst, ptr %src, i64 %size, i1 true)
ret void
}
; CHECK-LABEL: @memcpy_volatile_drop(
; INTERESTING: llvm.memcpy
; RESULT: call void @llvm.memcpy.p0.p0.i64(ptr %dst, ptr %src, i64 %size, i1 false)
define void @memcpy_volatile_drop(ptr %dst, ptr %src, i64 %size) {
call void @llvm.memcpy.p0.p0.i64(ptr %dst, ptr %src, i64 %size, i1 true)
ret void
}
; CHECK-LABEL: @memcpy_inline_volatile_keep(
; INTERESTING: i1 true
; RESULT: call void @llvm.memcpy.inline.p0.p0.i64(ptr %dst, ptr %src, i64 256, i1 true)
define void @memcpy_inline_volatile_keep(ptr %dst, ptr %src) {
call void @llvm.memcpy.inline.p0.p0.i64(ptr %dst, ptr %src, i64 256, i1 true)
ret void
}
; CHECK-LABEL: @memcpy_inline_volatile_drop(
; INTERESTING: llvm.memcpy
; RESULT: call void @llvm.memcpy.inline.p0.p0.i64(ptr %dst, ptr %src, i64 256, i1 false)
define void @memcpy_inline_volatile_drop(ptr %dst, ptr %src) {
call void @llvm.memcpy.inline.p0.p0.i64(ptr %dst, ptr %src, i64 256, i1 true)
ret void
}
; CHECK-LABEL: @memmove_volatile_keep(
; INTERESTING: i1 true
; RESULT: call void @llvm.memmove.p0.p0.i64(ptr %dst, ptr %src, i64 256, i1 true)
define void @memmove_volatile_keep(ptr %dst, ptr %src) {
call void @llvm.memmove.p0.p0.i64(ptr %dst, ptr %src, i64 256, i1 true)
ret void
}
; CHECK-LABEL: @memmove_volatile_drop(
; INTERESTING: llvm.memmove
; RESULT: call void @llvm.memmove.p0.p0.i64(ptr %dst, ptr %src, i64 %size, i1 false)
define void @memmove_volatile_drop(ptr %dst, ptr %src, i64 %size) {
call void @llvm.memmove.p0.p0.i64(ptr %dst, ptr %src, i64 %size, i1 true)
ret void
}
; CHECK-LABEL: @memset_volatile_keep(
; INTERESTING: i1 true
; RESULT: call void @llvm.memset.p0.i64(ptr %ptr, i8 %val, i64 %size, i1 true)
define void @memset_volatile_keep(ptr %ptr, i8 %val, i64 %size) {
call void @llvm.memset.p0.i64(ptr %ptr, i8 %val, i64 %size, i1 true)
ret void
}
; CHECK-LABEL: @memset_volatile_drop(
; INTERESTING: llvm.memset
; RESULT: call void @llvm.memset.p0.i64(ptr %ptr, i8 %val, i64 %size, i1 false)
define void @memset_volatile_drop(ptr %ptr, i8 %val, i64 %size) {
call void @llvm.memset.p0.i64(ptr %ptr, i8 %val, i64 %size, i1 true)
ret void
}
declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg)
declare void @llvm.memmove.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg)
declare void @llvm.memcpy.inline.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64 immarg, i1 immarg)
declare void @llvm.memset.p0.i64(ptr noalias nocapture readonly, i8, i64, i1 immarg)

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@ -39,6 +39,7 @@ add_llvm_tool(llvm-reduce
deltas/ReduceInstructionFlags.cpp
deltas/ReduceMetadata.cpp
deltas/ReduceModuleData.cpp
deltas/ReduceMemoryOperations.cpp
deltas/ReduceOperandBundles.cpp
deltas/ReduceOpcodes.cpp
deltas/ReduceSpecialGlobals.cpp

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@ -31,6 +31,7 @@
#include "deltas/ReduceInstructionFlagsMIR.h"
#include "deltas/ReduceInstructions.h"
#include "deltas/ReduceInstructionsMIR.h"
#include "deltas/ReduceMemoryOperations.h"
#include "deltas/ReduceMetadata.h"
#include "deltas/ReduceModuleData.h"
#include "deltas/ReduceOpcodes.h"
@ -94,6 +95,7 @@ static cl::list<std::string>
DELTA_PASS("attributes", reduceAttributesDeltaPass) \
DELTA_PASS("module-data", reduceModuleDataDeltaPass) \
DELTA_PASS("opcodes", reduceOpcodesDeltaPass) \
DELTA_PASS("volatile", reduceVolatileInstructionsDeltaPass) \
DELTA_PASS("instruction-flags", reduceInstructionFlagsDeltaPass) \
} while (false)

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@ -0,0 +1,44 @@
//===- ReduceOpcodes.cpp - Specialized Delta Pass -------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "ReduceMemoryOperations.h"
#include "Delta.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
static void removeVolatileInFunction(Oracle &O, Function &F) {
LLVMContext &Ctx = F.getContext();
for (Instruction &I : instructions(F)) {
if (LoadInst *LI = dyn_cast<LoadInst>(&I)) {
if (LI->isVolatile() && !O.shouldKeep())
LI->setVolatile(false);
} else if (StoreInst *SI = dyn_cast<StoreInst>(&I)) {
if (SI->isVolatile() && !O.shouldKeep())
SI->setVolatile(false);
} else if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(&I)) {
if (RMW->isVolatile() && !O.shouldKeep())
RMW->setVolatile(false);
} else if (AtomicCmpXchgInst *CmpXChg = dyn_cast<AtomicCmpXchgInst>(&I)) {
if (CmpXChg->isVolatile() && !O.shouldKeep())
CmpXChg->setVolatile(false);
} else if (MemIntrinsic *MemIntrin = dyn_cast<MemIntrinsic>(&I)) {
if (MemIntrin->isVolatile() && !O.shouldKeep())
MemIntrin->setVolatile(ConstantInt::getFalse(Ctx));
}
}
}
static void removeVolatileInModule(Oracle &O, Module &Mod) {
for (Function &F : Mod)
removeVolatileInFunction(O, F);
}
void llvm::reduceVolatileInstructionsDeltaPass(TestRunner &Test) {
runDeltaPass(Test, removeVolatileInModule, "Reducing Volatile Instructions");
}

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@ -0,0 +1,18 @@
//===- ReduceMemoryOperations.h - Specialized Delta Pass --------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TOOLS_LLVM_REDUCE_DELTAS_REDUCEMEMORYOPERATIONS_H
#define LLVM_TOOLS_LLVM_REDUCE_DELTAS_REDUCEMEMORYOPERATIONS_H
#include "TestRunner.h"
namespace llvm {
void reduceVolatileInstructionsDeltaPass(TestRunner &Test);
} // namespace llvm
#endif