[PATCH] D66529: [LOOPGUARD] Disable loop with multiple loop exiting blocks.
Whitney Tsang via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Wed Aug 21 10:34:32 PDT 2019
Whitney updated this revision to Diff 216428.
Whitney added a comment.
Add a test case with multiple loop exiting blocks.
Repository:
rL LLVM
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D66529/new/
https://reviews.llvm.org/D66529
Files:
llvm/lib/Analysis/LoopInfo.cpp
llvm/unittests/Analysis/LoopInfoTest.cpp
Index: llvm/unittests/Analysis/LoopInfoTest.cpp
===================================================================
--- llvm/unittests/Analysis/LoopInfoTest.cpp
+++ llvm/unittests/Analysis/LoopInfoTest.cpp
@@ -868,6 +868,64 @@
});
}
+TEST(LoopInfoTest, MultiExitingLoop) {
+ const char *ModuleStr =
+ "define void @foo(i32* %A, i32 %ub, i1 %cond) {\n"
+ "entry:\n"
+ " %guardcmp = icmp slt i32 0, %ub\n"
+ " br i1 %guardcmp, label %for.preheader, label %for.end\n"
+ "for.preheader:\n"
+ " br label %for.body\n"
+ "for.body:\n"
+ " %i = phi i32 [ 0, %for.preheader ], [ %inc, %for.body.1 ]\n"
+ " br i1 %cond, label %for.body.1, label %for.exit\n"
+ "for.body.1:\n"
+ " %idxprom = sext i32 %i to i64\n"
+ " %arrayidx = getelementptr inbounds i32, i32* %A, i64 %idxprom\n"
+ " store i32 %i, i32* %arrayidx, align 4\n"
+ " %inc = add nsw i32 %i, 1\n"
+ " %cmp = icmp slt i32 %inc, %ub\n"
+ " br i1 %cmp, label %for.body, label %for.exit\n"
+ "for.exit:\n"
+ " br label %for.end\n"
+ "for.end:\n"
+ " ret void\n"
+ "}\n";
+
+ // Parse the module.
+ LLVMContext Context;
+ std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleStr);
+
+ runWithLoopInfoPlus(
+ *M, "foo",
+ [&](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
+ Function::iterator FI = F.begin();
+ // First two basic block are entry and for.preheader - skip them.
+ ++FI;
+ BasicBlock *Header = &*(++FI);
+ assert(Header->getName() == "for.body");
+ Loop *L = LI.getLoopFor(Header);
+ EXPECT_NE(L, nullptr);
+
+ Optional<Loop::LoopBounds> Bounds = L->getBounds(SE);
+ EXPECT_NE(Bounds, None);
+ ConstantInt *InitialIVValue =
+ dyn_cast<ConstantInt>(&Bounds->getInitialIVValue());
+ EXPECT_TRUE(InitialIVValue && InitialIVValue->isZero());
+ EXPECT_EQ(Bounds->getStepInst().getName(), "inc");
+ ConstantInt *StepValue =
+ dyn_cast_or_null<ConstantInt>(Bounds->getStepValue());
+ EXPECT_TRUE(StepValue && StepValue->isOne());
+ EXPECT_EQ(Bounds->getFinalIVValue().getName(), "ub");
+ EXPECT_EQ(Bounds->getCanonicalPredicate(), ICmpInst::ICMP_SLT);
+ EXPECT_EQ(Bounds->getDirection(),
+ Loop::LoopBounds::Direction::Increasing);
+ EXPECT_EQ(L->getInductionVariable(SE)->getName(), "i");
+ EXPECT_EQ(L->getLoopGuardBranch(), nullptr);
+ EXPECT_FALSE(L->isGuarded());
+ });
+}
+
TEST(LoopInfoTest, UnguardedLoop) {
const char *ModuleStr =
"define void @foo(i32* %A, i32 %ub) {\n"
Index: llvm/lib/Analysis/LoopInfo.cpp
===================================================================
--- llvm/lib/Analysis/LoopInfo.cpp
+++ llvm/lib/Analysis/LoopInfo.cpp
@@ -367,6 +367,10 @@
"Expecting a loop with valid preheader and latch");
assert(isLoopExiting(Latch) && "Only valid for rotated loop");
+ BasicBlock *Exiting = getExitingBlock();
+ if (!Exiting)
+ return nullptr;
+
Instruction *LatchTI = Latch->getTerminator();
if (!LatchTI || LatchTI->getNumSuccessors() != 2)
return nullptr;
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