[llvm] 23c8da2 - [llvm-reduce] Add reduction for aliases.
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Wed Oct 28 06:13:05 PDT 2020
Author: Florian Hahn
Date: 2020-10-28T13:11:19Z
New Revision: 23c8da25ef79b31f8d014cb6135437e9061a4ce7
URL: https://github.com/llvm/llvm-project/commit/23c8da25ef79b31f8d014cb6135437e9061a4ce7
DIFF: https://github.com/llvm/llvm-project/commit/23c8da25ef79b31f8d014cb6135437e9061a4ce7.diff
LOG: [llvm-reduce] Add reduction for aliases.
This patch adds a new reduction pass that tries to remove aliases.
It runs early, as most of those likely can be removed up-front in
practice.
This substantially improves llvm-reduce for IR generated by the swift
compiler, which can generate a lot of aliases which lead to lots of
invalid reductions.
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D90260
Added:
llvm/tools/llvm-reduce/deltas/ReduceAliases.cpp
llvm/tools/llvm-reduce/deltas/ReduceAliases.h
Modified:
llvm/test/Reduce/remove-alias.ll
llvm/tools/llvm-reduce/CMakeLists.txt
llvm/tools/llvm-reduce/DeltaManager.h
Removed:
################################################################################
diff --git a/llvm/test/Reduce/remove-alias.ll b/llvm/test/Reduce/remove-alias.ll
index 715b58e1a741..48b39d26ee26 100644
--- a/llvm/test/Reduce/remove-alias.ll
+++ b/llvm/test/Reduce/remove-alias.ll
@@ -8,20 +8,20 @@
; CHECK-FINAL: @g1 = global
; CHECK-FINAL: @g2 = global
-; CHECK-FINAL: $a1
-; CHECK-FINAL: $a2
-; CHECK-FINAL: $a3
-; CHECK-FINAL: $a4
+; CHECK-FINAL-NOT: $a1
+; CHECK-FINAL-NOT: $a2
+; CHECK-FINAL-NOT: $a3
+; CHECK-FINAL-NOT: $a4
; CHECK-FINAL: $a5
; CHECK-FINAL: $a6
; CHECK-FINAL-NOT: @llvm.used
; CHECK-FINAL-NOT: @llvm.compiler.used
-; CHECK-FINAL: define void @fn1
-; CHECK-FINAL: define void @fn2
+; CHECK-FINAL-NOT: define void @fn1
+; CHECK-FINAL-NOT: define void @fn2
; CHECK-FINAL: define void @fn3
-; CHECK-FINAL: define void @fn4
+; CHECK-FINAL-NOT: define void @fn4
@g1 = global [ 4 x i32 ] zeroinitializer
@g2 = global [ 4 x i32 ] zeroinitializer
diff --git a/llvm/tools/llvm-reduce/CMakeLists.txt b/llvm/tools/llvm-reduce/CMakeLists.txt
index 81b4e95eece5..cbe9978c10a8 100644
--- a/llvm/tools/llvm-reduce/CMakeLists.txt
+++ b/llvm/tools/llvm-reduce/CMakeLists.txt
@@ -13,6 +13,7 @@ set(LLVM_LINK_COMPONENTS
add_llvm_tool(llvm-reduce
TestRunner.cpp
deltas/Delta.cpp
+ deltas/ReduceAliases.cpp
deltas/ReduceArguments.cpp
deltas/ReduceAttributes.cpp
deltas/ReduceBasicBlocks.cpp
diff --git a/llvm/tools/llvm-reduce/DeltaManager.h b/llvm/tools/llvm-reduce/DeltaManager.h
index 83278c88791b..8c9ccca69309 100644
--- a/llvm/tools/llvm-reduce/DeltaManager.h
+++ b/llvm/tools/llvm-reduce/DeltaManager.h
@@ -13,6 +13,7 @@
#include "TestRunner.h"
#include "deltas/Delta.h"
+#include "deltas/ReduceAliases.h"
#include "deltas/ReduceArguments.h"
#include "deltas/ReduceAttributes.h"
#include "deltas/ReduceBasicBlocks.h"
@@ -27,6 +28,7 @@ namespace llvm {
// TODO: Add CLI option to run only specified Passes (for unit tests)
inline void runDeltaPasses(TestRunner &Tester) {
+ reduceAliasesDeltaPass(Tester);
reduceFunctionBodiesDeltaPass(Tester);
reduceFunctionsDeltaPass(Tester);
reduceBasicBlocksDeltaPass(Tester);
diff --git a/llvm/tools/llvm-reduce/deltas/ReduceAliases.cpp b/llvm/tools/llvm-reduce/deltas/ReduceAliases.cpp
new file mode 100644
index 000000000000..41be4baa980a
--- /dev/null
+++ b/llvm/tools/llvm-reduce/deltas/ReduceAliases.cpp
@@ -0,0 +1,53 @@
+//===- ReduceAliases.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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a function which calls the Generic Delta pass in order
+// to reduce aliases in the provided Module.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ReduceAliases.h"
+#include "Delta.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/GlobalValue.h"
+
+using namespace llvm;
+
+/// Removes all aliases aren't inside any of the
+/// desired Chunks.
+static void extractAliasesFromModule(const std::vector<Chunk> &ChunksToKeep,
+ Module *Program) {
+ Oracle O(ChunksToKeep);
+
+ for (auto &GA : make_early_inc_range(Program->aliases())) {
+ if (!O.shouldKeep()) {
+ GA.replaceAllUsesWith(GA.getAliasee());
+ GA.eraseFromParent();
+ }
+ }
+}
+
+/// Counts the amount of aliases and prints their respective name & index.
+static int countAliases(Module *Program) {
+ // TODO: Silence index with --quiet flag
+ errs() << "----------------------------\n";
+ errs() << "Aliases Index Reference:\n";
+ int Count = 0;
+ for (auto &GA : Program->aliases())
+ errs() << "\t" << ++Count << ": " << GA.getName() << "\n";
+
+ errs() << "----------------------------\n";
+ return Count;
+}
+
+void llvm::reduceAliasesDeltaPass(TestRunner &Test) {
+ errs() << "*** Reducing Aliases ...\n";
+ int Functions = countAliases(Test.getProgram());
+ runDeltaPass(Test, Functions, extractAliasesFromModule);
+ errs() << "----------------------------\n";
+}
diff --git a/llvm/tools/llvm-reduce/deltas/ReduceAliases.h b/llvm/tools/llvm-reduce/deltas/ReduceAliases.h
new file mode 100644
index 000000000000..0c2886e0c225
--- /dev/null
+++ b/llvm/tools/llvm-reduce/deltas/ReduceAliases.h
@@ -0,0 +1,18 @@
+//===- ReduceAliases.h - 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a function which calls the Generic Delta pass in order
+// to reduce aliases in the provided Module.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Delta.h"
+
+namespace llvm {
+void reduceAliasesDeltaPass(TestRunner &Test);
+} // namespace llvm
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