llvm-reduce: Add volatile reduction pass

[arsenm]

Summary

Removing volatile may help optimization passes do more to the IR. However,
this will increase scheduler freedom.

[arsenm]

596fdf75d99f83473295e6a619ffac5afa23dd8e

llvm/test/tools/llvm-reduce/reduce-volatile.ll

+; 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)

llvm/tools/llvm-reduce/CMakeLists.txt

add_llvm_tool(llvm-reduce
   deltas/ReduceGlobalObjects.cpp
   deltas/ReduceGlobalValues.cpp
   deltas/ReduceGlobalVarInitializers.cpp
   deltas/ReduceGlobalVars.cpp
   deltas/ReduceInstructions.cpp
   deltas/ReduceInstructionFlags.cpp
   deltas/ReduceMetadata.cpp
   deltas/ReduceModuleData.cpp
+  deltas/ReduceMemoryOperations.cpp
   deltas/ReduceOperandBundles.cpp
   deltas/ReduceOpcodes.cpp
   deltas/ReduceSpecialGlobals.cpp
   deltas/ReduceOperands.cpp
   deltas/ReduceOperandsSkip.cpp
   deltas/ReduceOperandsToArgs.cpp
   deltas/ReduceInstructionsMIR.cpp
   deltas/ReduceInstructionFlagsMIR.cpp

llvm/tools/llvm-reduce/DeltaManager.cpp

 #include "deltas/ReduceGlobalValues.h"
 #include "deltas/ReduceGlobalVarInitializers.h"
 #include "deltas/ReduceGlobalVars.h"
 #include "deltas/ReduceIRReferences.h"
 #include "deltas/ReduceInstructionFlags.h"
 #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"
 #include "deltas/ReduceOperandBundles.h"
 #include "deltas/ReduceOperands.h"
 #include "deltas/ReduceOperandsSkip.h"
 #include "deltas/ReduceOperandsToArgs.h"
 #include "deltas/ReduceRegisterDefs.h"
do {                                                                         \
     DELTA_PASS("operands-one", reduceOperandsOneDeltaPass)                     \
     DELTA_PASS("operands-nan", reduceOperandsNaNDeltaPass)                     \
     DELTA_PASS("operands-to-args", reduceOperandsToArgsDeltaPass)              \
     DELTA_PASS("operands-skip", reduceOperandsSkipDeltaPass)                   \
     DELTA_PASS("operand-bundles", reduceOperandBundesDeltaPass)                \
     DELTA_PASS("attributes", reduceAttributesDeltaPass)                        \
     DELTA_PASS("module-data", reduceModuleDataDeltaPass)                       \
     DELTA_PASS("opcodes", reduceOpcodesDeltaPass)                              \
+    DELTA_PASS("volatile", reduceVolatileInstructionsDeltaPass)                \
     DELTA_PASS("instruction-flags", reduceInstructionFlagsDeltaPass)           \
 } while (false)
 
 #define DELTA_PASSES_MIR                                                       \
   do {                                                                         \
     DELTA_PASS("instructions", reduceInstructionsMIRDeltaPass)                 \
     DELTA_PASS("ir-instruction-references",                                    \
                reduceIRInstructionReferencesDeltaPass)                         \

llvm/tools/llvm-reduce/deltas/ReduceMemoryOperations.h

+//===- 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

llvm/tools/llvm-reduce/deltas/ReduceMemoryOperations.cpp

+//===- 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");
+}