[llvm] r323928 - Utils: Fix DomTree update for entry block
Matt Arsenault via llvm-commits
llvm-commits at lists.llvm.org
Wed Jan 31 14:54:37 PST 2018
Author: arsenm
Date: Wed Jan 31 14:54:37 2018
New Revision: 323928
URL: http://llvm.org/viewvc/llvm-project?rev=323928&view=rev
Log:
Utils: Fix DomTree update for entry block
If SplitBlockPredecessors was used on a function entry block,
it wouldn't update the dominator tree.
Added:
llvm/trunk/unittests/Transforms/Utils/BasicBlockUtils.cpp
Modified:
llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp
llvm/trunk/unittests/Transforms/Utils/CMakeLists.txt
llvm/trunk/unittests/Transforms/Utils/Local.cpp
Modified: llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp?rev=323928&r1=323927&r2=323928&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp Wed Jan 31 14:54:37 2018
@@ -319,8 +319,15 @@ static void UpdateAnalysisInformation(Ba
DominatorTree *DT, LoopInfo *LI,
bool PreserveLCSSA, bool &HasLoopExit) {
// Update dominator tree if available.
- if (DT)
- DT->splitBlock(NewBB);
+ if (DT) {
+ if (OldBB == DT->getRootNode()->getBlock()) {
+ assert(NewBB == &NewBB->getParent()->getEntryBlock());
+ DT->setNewRoot(NewBB);
+ } else {
+ // Split block expects NewBB to have a non-empty set of predecessors.
+ DT->splitBlock(NewBB);
+ }
+ }
// The rest of the logic is only relevant for updating the loop structures.
if (!LI)
@@ -504,7 +511,6 @@ BasicBlock *llvm::SplitBlockPredecessors
// Insert dummy values as the incoming value.
for (BasicBlock::iterator I = BB->begin(); isa<PHINode>(I); ++I)
cast<PHINode>(I)->addIncoming(UndefValue::get(I->getType()), NewBB);
- return NewBB;
}
// Update DominatorTree, LoopInfo, and LCCSA analysis information.
@@ -512,8 +518,11 @@ BasicBlock *llvm::SplitBlockPredecessors
UpdateAnalysisInformation(BB, NewBB, Preds, DT, LI, PreserveLCSSA,
HasLoopExit);
- // Update the PHI nodes in BB with the values coming from NewBB.
- UpdatePHINodes(BB, NewBB, Preds, BI, HasLoopExit);
+ if (!Preds.empty()) {
+ // Update the PHI nodes in BB with the values coming from NewBB.
+ UpdatePHINodes(BB, NewBB, Preds, BI, HasLoopExit);
+ }
+
return NewBB;
}
Added: llvm/trunk/unittests/Transforms/Utils/BasicBlockUtils.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Transforms/Utils/BasicBlockUtils.cpp?rev=323928&view=auto
==============================================================================
--- llvm/trunk/unittests/Transforms/Utils/BasicBlockUtils.cpp (added)
+++ llvm/trunk/unittests/Transforms/Utils/BasicBlockUtils.cpp Wed Jan 31 14:54:37 2018
@@ -0,0 +1,52 @@
+//===- BasicBlockUtils.cpp - Unit tests for BasicBlockUtils ---------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/AsmParser/Parser.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/Support/SourceMgr.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+static std::unique_ptr<Module> parseIR(LLVMContext &C, const char *IR) {
+ SMDiagnostic Err;
+ std::unique_ptr<Module> Mod = parseAssemblyString(IR, Err, C);
+ if (!Mod)
+ Err.print("BasicBlockUtilsTests", errs());
+ return Mod;
+}
+
+TEST(BasicBlockUtils, SplitBlockPredecessors) {
+ LLVMContext C;
+
+ std::unique_ptr<Module> M = parseIR(
+ C,
+ "define i32 @basic_func(i1 %cond) {\n"
+ "entry:\n"
+ " br i1 %cond, label %bb0, label %bb1\n"
+ "bb0:\n"
+ " br label %bb1\n"
+ "bb1:\n"
+ " %phi = phi i32 [ 0, %entry ], [ 1, %bb0 ]"
+ " ret i32 %phi\n"
+ "}\n"
+ "\n"
+ );
+
+ auto *F = M->getFunction("basic_func");
+ DominatorTree DT(*F);
+
+ // Make sure the dominator tree is properly updated if calling this on the
+ // entry block.
+ SplitBlockPredecessors(&F->getEntryBlock(), {}, "split.entry", &DT);
+ EXPECT_TRUE(DT.verify());
+}
Modified: llvm/trunk/unittests/Transforms/Utils/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Transforms/Utils/CMakeLists.txt?rev=323928&r1=323927&r2=323928&view=diff
==============================================================================
--- llvm/trunk/unittests/Transforms/Utils/CMakeLists.txt (original)
+++ llvm/trunk/unittests/Transforms/Utils/CMakeLists.txt Wed Jan 31 14:54:37 2018
@@ -8,6 +8,7 @@ set(LLVM_LINK_COMPONENTS
add_llvm_unittest(UtilsTests
ASanStackFrameLayoutTest.cpp
+ BasicBlockUtils.cpp
Cloning.cpp
CodeExtractor.cpp
FunctionComparator.cpp
Modified: llvm/trunk/unittests/Transforms/Utils/Local.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Transforms/Utils/Local.cpp?rev=323928&r1=323927&r2=323928&view=diff
==============================================================================
--- llvm/trunk/unittests/Transforms/Utils/Local.cpp (original)
+++ llvm/trunk/unittests/Transforms/Utils/Local.cpp Wed Jan 31 14:54:37 2018
@@ -100,7 +100,7 @@ TEST(Local, RemoveDuplicatePHINodes) {
EXPECT_EQ(3U, BB->size());
}
-std::unique_ptr<Module> parseIR(LLVMContext &C, const char *IR) {
+static std::unique_ptr<Module> parseIR(LLVMContext &C, const char *IR) {
SMDiagnostic Err;
std::unique_ptr<Module> Mod = parseAssemblyString(IR, Err, C);
if (!Mod)
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