Save the induction binary operator in IVDescriptors for non FP induction variables.
Summary:
Currently InductionBinOps are only saved for FP induction variables, the PR extends it with non FP induction variable, so user of IVDescriptors can query the InductionBinOps for integer induction variables.
The changes in hasUnsafeAlgebra() and getUnsafeAlgebraInst() are required for the existing LIT test cases to pass. As described in the comment of the two functions, one of the requirement to return true is it is a FP induction variable. The checks was not needed because InductionBinOp was not set on non FP cases before.
https://reviews.llvm.org/D60565 depends on the patch.
Committed on behalf of @Whitney (Whitney Tsang).
Reviewers: jdoerfert, kbarton, fhahn, hfinkel, dmgreen, Meinersbur
Reviewed By: jdoerfert
Subscribers: mgorny, hiraditya, jsji, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61329
llvm-svn: 360671
diff --git a/llvm/include/llvm/Analysis/IVDescriptors.h b/llvm/include/llvm/Analysis/IVDescriptors.h
index 4e8b6ec..7be1fd3 100644
--- a/llvm/include/llvm/Analysis/IVDescriptors.h
+++ b/llvm/include/llvm/Analysis/IVDescriptors.h
@@ -315,12 +315,16 @@
/// not have the "fast-math" property. Such operation requires a relaxed FP
/// mode.
bool hasUnsafeAlgebra() {
- return InductionBinOp && !cast<FPMathOperator>(InductionBinOp)->isFast();
+ return (IK == IK_FpInduction) && InductionBinOp &&
+ !cast<FPMathOperator>(InductionBinOp)->isFast();
}
/// Returns induction operator that does not have "fast-math" property
/// and requires FP unsafe mode.
Instruction *getUnsafeAlgebraInst() {
+ if (IK != IK_FpInduction)
+ return nullptr;
+
if (!InductionBinOp || cast<FPMathOperator>(InductionBinOp)->isFast())
return nullptr;
return InductionBinOp;
diff --git a/llvm/lib/Analysis/IVDescriptors.cpp b/llvm/lib/Analysis/IVDescriptors.cpp
index 19f1a77..ce285f8 100644
--- a/llvm/lib/Analysis/IVDescriptors.cpp
+++ b/llvm/lib/Analysis/IVDescriptors.cpp
@@ -1053,6 +1053,13 @@
Value *StartValue =
Phi->getIncomingValueForBlock(AR->getLoop()->getLoopPreheader());
+
+ BasicBlock *Latch = AR->getLoop()->getLoopLatch();
+ if (!Latch)
+ return false;
+ BinaryOperator *BOp =
+ dyn_cast<BinaryOperator>(Phi->getIncomingValueForBlock(Latch));
+
const SCEV *Step = AR->getStepRecurrence(*SE);
// Calculate the pointer stride and check if it is consecutive.
// The stride may be a constant or a loop invariant integer value.
@@ -1061,7 +1068,7 @@
return false;
if (PhiTy->isIntegerTy()) {
- D = InductionDescriptor(StartValue, IK_IntInduction, Step, /*BOp=*/nullptr,
+ D = InductionDescriptor(StartValue, IK_IntInduction, Step, BOp,
CastsToIgnore);
return true;
}
@@ -1088,6 +1095,6 @@
return false;
auto *StepValue =
SE->getConstant(CV->getType(), CVSize / Size, true /* signed */);
- D = InductionDescriptor(StartValue, IK_PtrInduction, StepValue);
+ D = InductionDescriptor(StartValue, IK_PtrInduction, StepValue, BOp);
return true;
}
diff --git a/llvm/unittests/Analysis/CMakeLists.txt b/llvm/unittests/Analysis/CMakeLists.txt
index 45d31f8..20b4ae2 100644
--- a/llvm/unittests/Analysis/CMakeLists.txt
+++ b/llvm/unittests/Analysis/CMakeLists.txt
@@ -18,6 +18,7 @@
DivergenceAnalysisTest.cpp
DomTreeUpdaterTest.cpp
GlobalsModRefTest.cpp
+ IVDescriptorsTest.cpp
LazyCallGraphTest.cpp
LoopInfoTest.cpp
MemoryBuiltinsTest.cpp
diff --git a/llvm/unittests/Analysis/IVDescriptorsTest.cpp b/llvm/unittests/Analysis/IVDescriptorsTest.cpp
new file mode 100644
index 0000000..cba45a9
--- /dev/null
+++ b/llvm/unittests/Analysis/IVDescriptorsTest.cpp
@@ -0,0 +1,100 @@
+//===- IVDescriptorsTest.cpp - IVDescriptors unit tests -------------------===//
+//
+// 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 "llvm/Analysis/IVDescriptors.h"
+#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/AsmParser/Parser.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/Support/SourceMgr.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+/// Build the loop info and scalar evolution for the function and run the Test.
+static void runWithLoopInfoAndSE(
+ Module &M, StringRef FuncName,
+ function_ref<void(Function &F, LoopInfo &LI, ScalarEvolution &SE)> Test) {
+ auto *F = M.getFunction(FuncName);
+ ASSERT_NE(F, nullptr) << "Could not find " << FuncName;
+
+ TargetLibraryInfoImpl TLII;
+ TargetLibraryInfo TLI(TLII);
+ AssumptionCache AC(*F);
+ DominatorTree DT(*F);
+ LoopInfo LI(DT);
+ ScalarEvolution SE(*F, TLI, AC, DT, LI);
+
+ Test(*F, LI, SE);
+}
+
+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("IVDescriptorsTests", errs());
+ return Mod;
+}
+
+// This tests that IVDescriptors can obtain the induction binary operator for
+// integer induction variables. And hasUnsafeAlgebra() and
+// getUnsafeAlgebraInst() correctly return the expected behavior, i.e. no unsafe
+// algebra.
+TEST(IVDescriptorsTest, LoopWithSingleLatch) {
+ // Parse the module.
+ LLVMContext Context;
+
+ std::unique_ptr<Module> M = parseIR(
+ Context,
+ R"(define void @foo(i32* %A, i32 %ub) {
+entry:
+ br label %for.body
+for.body:
+ %i = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+ %idxprom = sext i32 %i to i64
+ %arrayidx = getelementptr inbounds i32, i32* %A, i64 %idxprom
+ store i32 %i, i32* %arrayidx, align 4
+ %inc = add nsw i32 %i, 1
+ %cmp = icmp slt i32 %inc, %ub
+ br i1 %cmp, label %for.body, label %for.exit
+for.exit:
+ br label %for.end
+for.end:
+ ret void
+})"
+ );
+
+ runWithLoopInfoAndSE(
+ *M, "foo", [&](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
+ Function::iterator FI = F.begin();
+ // First basic block is entry - skip it.
+ BasicBlock *Header = &*(++FI);
+ assert(Header->getName() == "for.body");
+ Loop *L = LI.getLoopFor(Header);
+ EXPECT_NE(L, nullptr);
+ PHINode *Inst_i = dyn_cast<PHINode>(&Header->front());
+ assert(Inst_i->getName() == "i");
+ InductionDescriptor IndDesc;
+ bool IsInductionPHI =
+ InductionDescriptor::isInductionPHI(Inst_i, L, &SE, IndDesc);
+ EXPECT_TRUE(IsInductionPHI);
+ Instruction *Inst_inc = nullptr;
+ BasicBlock::iterator BBI = Header->begin();
+ do {
+ if ((&*BBI)->getName() == "inc")
+ Inst_inc = &*BBI;
+ ++BBI;
+ } while (!Inst_inc);
+ assert(Inst_inc->getName() == "inc");
+ EXPECT_EQ(IndDesc.getInductionBinOp(), Inst_inc);
+ EXPECT_FALSE(IndDesc.hasUnsafeAlgebra());
+ EXPECT_EQ(IndDesc.getUnsafeAlgebraInst(), nullptr);
+ });
+}