[llvm] r363106 - [Analysis] add isSplatValue() for vectors in IR
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Tue Jun 11 15:25:18 PDT 2019
Author: spatel
Date: Tue Jun 11 15:25:18 2019
New Revision: 363106
URL: http://llvm.org/viewvc/llvm-project?rev=363106&view=rev
Log:
[Analysis] add isSplatValue() for vectors in IR
We have the related getSplatValue() already in IR (see code just above the proposed addition).
But sometimes we only need to know that the value is a splat rather than capture the splatted
scalar value. Also, we have an isSplatValue() function already in SDAG.
Motivation - recent bugs that would potentially benefit from improved splat analysis in IR:
https://bugs.llvm.org/show_bug.cgi?id=37428
https://bugs.llvm.org/show_bug.cgi?id=42174
Differential Revision: https://reviews.llvm.org/D63138
Modified:
llvm/trunk/include/llvm/Analysis/VectorUtils.h
llvm/trunk/lib/Analysis/VectorUtils.cpp
llvm/trunk/unittests/Analysis/VectorUtilsTest.cpp
Modified: llvm/trunk/include/llvm/Analysis/VectorUtils.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/VectorUtils.h?rev=363106&r1=363105&r2=363106&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/VectorUtils.h (original)
+++ llvm/trunk/include/llvm/Analysis/VectorUtils.h Tue Jun 11 15:25:18 2019
@@ -78,6 +78,12 @@ Value *findScalarElement(Value *V, unsig
/// a sequence of instructions that broadcast a single value into a vector.
const Value *getSplatValue(const Value *V);
+/// Return true if the input value is known to be a vector with all identical
+/// elements (potentially including undefined elements).
+/// This may be more powerful than the related getSplatValue() because it is
+/// not limited by finding a scalar source value to a splatted vector.
+bool isSplatValue(const Value *V, unsigned Depth = 0);
+
/// Compute a map of integer instructions to their minimum legal type
/// size.
///
Modified: llvm/trunk/lib/Analysis/VectorUtils.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/VectorUtils.cpp?rev=363106&r1=363105&r2=363106&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/VectorUtils.cpp (original)
+++ llvm/trunk/lib/Analysis/VectorUtils.cpp Tue Jun 11 15:25:18 2019
@@ -321,6 +321,45 @@ const llvm::Value *llvm::getSplatValue(c
return nullptr;
}
+// This setting is based on its counterpart in value tracking, but it could be
+// adjusted if needed.
+const unsigned MaxDepth = 6;
+
+bool llvm::isSplatValue(const Value *V, unsigned Depth) {
+ assert(Depth <= MaxDepth && "Limit Search Depth");
+
+ if (isa<VectorType>(V->getType())) {
+ if (isa<UndefValue>(V))
+ return true;
+ // FIXME: Constant splat analysis does not allow undef elements.
+ if (auto *C = dyn_cast<Constant>(V))
+ return C->getSplatValue() != nullptr;
+ }
+
+ // FIXME: Constant splat analysis does not allow undef elements.
+ Constant *Mask;
+ if (match(V, m_ShuffleVector(m_Value(), m_Value(), m_Constant(Mask))))
+ return Mask->getSplatValue() != nullptr;
+
+ // The remaining tests are all recursive, so bail out if we hit the limit.
+ if (Depth++ == MaxDepth)
+ return false;
+
+ // If both operands of a binop are splats, the result is a splat.
+ Value *X, *Y, *Z;
+ if (match(V, m_BinOp(m_Value(X), m_Value(Y))))
+ return isSplatValue(X, Depth) && isSplatValue(Y, Depth);
+
+ // If all operands of a select are splats, the result is a splat.
+ if (match(V, m_Select(m_Value(X), m_Value(Y), m_Value(Z))))
+ return isSplatValue(X, Depth) && isSplatValue(Y, Depth) &&
+ isSplatValue(Z, Depth);
+
+ // TODO: Add support for unary ops (fneg), casts, intrinsics (overflow ops).
+
+ return false;
+}
+
MapVector<Instruction *, uint64_t>
llvm::computeMinimumValueSizes(ArrayRef<BasicBlock *> Blocks, DemandedBits &DB,
const TargetTransformInfo *TTI) {
Modified: llvm/trunk/unittests/Analysis/VectorUtilsTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Analysis/VectorUtilsTest.cpp?rev=363106&r1=363105&r2=363106&view=diff
==============================================================================
--- llvm/trunk/unittests/Analysis/VectorUtilsTest.cpp (original)
+++ llvm/trunk/unittests/Analysis/VectorUtilsTest.cpp Tue Jun 11 15:25:18 2019
@@ -11,8 +11,10 @@
#include "llvm/AsmParser/Parser.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
+#include "llvm/IR/NoFolder.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/KnownBits.h"
@@ -56,8 +58,196 @@ protected:
Instruction *A;
};
+struct BasicTest : public testing::Test {
+ LLVMContext Ctx;
+ std::unique_ptr<Module> M;
+ Function *F;
+ BasicBlock *BB;
+ IRBuilder<NoFolder> IRB;
+
+ BasicTest()
+ : M(new Module("VectorUtils", Ctx)),
+ F(Function::Create(
+ FunctionType::get(Type::getVoidTy(Ctx), /* IsVarArg */ false),
+ Function::ExternalLinkage, "f", M.get())),
+ BB(BasicBlock::Create(Ctx, "entry", F)), IRB(BB) {}
+};
+
+
} // namespace
+TEST_F(BasicTest, isSplat) {
+ Value *UndefVec = UndefValue::get(VectorType::get(IRB.getInt8Ty(), 4));
+ EXPECT_TRUE(isSplatValue(UndefVec));
+
+ Constant *UndefScalar = UndefValue::get(IRB.getInt8Ty());
+ EXPECT_FALSE(isSplatValue(UndefScalar));
+
+ Constant *ScalarC = IRB.getInt8(42);
+ EXPECT_FALSE(isSplatValue(ScalarC));
+
+ Constant *OtherScalarC = IRB.getInt8(-42);
+ Constant *NonSplatC = ConstantVector::get({ScalarC, OtherScalarC});
+ EXPECT_FALSE(isSplatValue(NonSplatC));
+
+ Value *SplatC = IRB.CreateVectorSplat(5, ScalarC);
+ EXPECT_TRUE(isSplatValue(SplatC));
+
+ // FIXME: Constant splat analysis does not allow undef elements.
+ Constant *SplatWithUndefC = ConstantVector::get({ScalarC, UndefScalar});
+ EXPECT_FALSE(isSplatValue(SplatWithUndefC));
+}
+
+TEST_F(VectorUtilsTest, isSplatValue_00) {
+ parseAssembly(
+ "define <2 x i8> @test(<2 x i8> %x) {\n"
+ " %A = shufflevector <2 x i8> %x, <2 x i8> undef, <2 x i32> zeroinitializer\n"
+ " ret <2 x i8> %A\n"
+ "}\n");
+ EXPECT_TRUE(isSplatValue(A));
+}
+
+TEST_F(VectorUtilsTest, isSplatValue_11) {
+ parseAssembly(
+ "define <2 x i8> @test(<2 x i8> %x) {\n"
+ " %A = shufflevector <2 x i8> %x, <2 x i8> undef, <2 x i32> <i32 1, i32 1>\n"
+ " ret <2 x i8> %A\n"
+ "}\n");
+ EXPECT_TRUE(isSplatValue(A));
+}
+
+TEST_F(VectorUtilsTest, isSplatValue_01) {
+ parseAssembly(
+ "define <2 x i8> @test(<2 x i8> %x) {\n"
+ " %A = shufflevector <2 x i8> %x, <2 x i8> undef, <2 x i32> <i32 0, i32 1>\n"
+ " ret <2 x i8> %A\n"
+ "}\n");
+ EXPECT_FALSE(isSplatValue(A));
+}
+
+// FIXME: Constant (mask) splat analysis does not allow undef elements.
+
+TEST_F(VectorUtilsTest, isSplatValue_0u) {
+ parseAssembly(
+ "define <2 x i8> @test(<2 x i8> %x) {\n"
+ " %A = shufflevector <2 x i8> %x, <2 x i8> undef, <2 x i32> <i32 0, i32 undef>\n"
+ " ret <2 x i8> %A\n"
+ "}\n");
+ EXPECT_FALSE(isSplatValue(A));
+}
+
+TEST_F(VectorUtilsTest, isSplatValue_Binop) {
+ parseAssembly(
+ "define <2 x i8> @test(<2 x i8> %x) {\n"
+ " %v0 = shufflevector <2 x i8> %x, <2 x i8> undef, <2 x i32> <i32 0, i32 0>\n"
+ " %v1 = shufflevector <2 x i8> %x, <2 x i8> undef, <2 x i32> <i32 1, i32 1>\n"
+ " %A = udiv <2 x i8> %v0, %v1\n"
+ " ret <2 x i8> %A\n"
+ "}\n");
+ EXPECT_TRUE(isSplatValue(A));
+}
+
+TEST_F(VectorUtilsTest, isSplatValue_Binop_ConstantOp0) {
+ parseAssembly(
+ "define <2 x i8> @test(<2 x i8> %x) {\n"
+ " %v1 = shufflevector <2 x i8> %x, <2 x i8> undef, <2 x i32> <i32 1, i32 1>\n"
+ " %A = ashr <2 x i8> <i8 42, i8 42>, %v1\n"
+ " ret <2 x i8> %A\n"
+ "}\n");
+ EXPECT_TRUE(isSplatValue(A));
+}
+
+TEST_F(VectorUtilsTest, isSplatValue_Binop_Not_Op0) {
+ parseAssembly(
+ "define <2 x i8> @test(<2 x i8> %x) {\n"
+ " %v0 = shufflevector <2 x i8> %x, <2 x i8> undef, <2 x i32> <i32 1, i32 0>\n"
+ " %v1 = shufflevector <2 x i8> %x, <2 x i8> undef, <2 x i32> <i32 1, i32 1>\n"
+ " %A = add <2 x i8> %v0, %v1\n"
+ " ret <2 x i8> %A\n"
+ "}\n");
+ EXPECT_FALSE(isSplatValue(A));
+}
+
+TEST_F(VectorUtilsTest, isSplatValue_Binop_Not_Op1) {
+ parseAssembly(
+ "define <2 x i8> @test(<2 x i8> %x) {\n"
+ " %v0 = shufflevector <2 x i8> %x, <2 x i8> undef, <2 x i32> <i32 1, i32 1>\n"
+ " %v1 = shufflevector <2 x i8> %x, <2 x i8> undef, <2 x i32> <i32 0, i32 1>\n"
+ " %A = shl <2 x i8> %v0, %v1\n"
+ " ret <2 x i8> %A\n"
+ "}\n");
+ EXPECT_FALSE(isSplatValue(A));
+}
+
+TEST_F(VectorUtilsTest, isSplatValue_Select) {
+ parseAssembly(
+ "define <2 x i8> @test(<2 x i1> %x, <2 x i8> %y, <2 x i8> %z) {\n"
+ " %v0 = shufflevector <2 x i1> %x, <2 x i1> undef, <2 x i32> <i32 1, i32 1>\n"
+ " %v1 = shufflevector <2 x i8> %y, <2 x i8> undef, <2 x i32> <i32 0, i32 0>\n"
+ " %v2 = shufflevector <2 x i8> %z, <2 x i8> undef, <2 x i32> <i32 1, i32 1>\n"
+ " %A = select <2 x i1> %v0, <2 x i8> %v1, <2 x i8> %v2\n"
+ " ret <2 x i8> %A\n"
+ "}\n");
+ EXPECT_TRUE(isSplatValue(A));
+}
+
+TEST_F(VectorUtilsTest, isSplatValue_Select_ConstantOp) {
+ parseAssembly(
+ "define <2 x i8> @test(<2 x i1> %x, <2 x i8> %y, <2 x i8> %z) {\n"
+ " %v0 = shufflevector <2 x i1> %x, <2 x i1> undef, <2 x i32> <i32 1, i32 1>\n"
+ " %v2 = shufflevector <2 x i8> %z, <2 x i8> undef, <2 x i32> <i32 1, i32 1>\n"
+ " %A = select <2 x i1> %v0, <2 x i8> <i8 42, i8 42>, <2 x i8> %v2\n"
+ " ret <2 x i8> %A\n"
+ "}\n");
+ EXPECT_TRUE(isSplatValue(A));
+}
+
+TEST_F(VectorUtilsTest, isSplatValue_Select_NotCond) {
+ parseAssembly(
+ "define <2 x i8> @test(<2 x i1> %x, <2 x i8> %y, <2 x i8> %z) {\n"
+ " %v1 = shufflevector <2 x i8> %y, <2 x i8> undef, <2 x i32> <i32 0, i32 0>\n"
+ " %v2 = shufflevector <2 x i8> %z, <2 x i8> undef, <2 x i32> <i32 1, i32 1>\n"
+ " %A = select <2 x i1> %x, <2 x i8> %v1, <2 x i8> %v2\n"
+ " ret <2 x i8> %A\n"
+ "}\n");
+ EXPECT_FALSE(isSplatValue(A));
+}
+
+TEST_F(VectorUtilsTest, isSplatValue_Select_NotOp1) {
+ parseAssembly(
+ "define <2 x i8> @test(<2 x i1> %x, <2 x i8> %y, <2 x i8> %z) {\n"
+ " %v0 = shufflevector <2 x i1> %x, <2 x i1> undef, <2 x i32> <i32 1, i32 1>\n"
+ " %v2 = shufflevector <2 x i8> %z, <2 x i8> undef, <2 x i32> <i32 1, i32 1>\n"
+ " %A = select <2 x i1> %v0, <2 x i8> %y, <2 x i8> %v2\n"
+ " ret <2 x i8> %A\n"
+ "}\n");
+ EXPECT_FALSE(isSplatValue(A));
+}
+
+TEST_F(VectorUtilsTest, isSplatValue_Select_NotOp2) {
+ parseAssembly(
+ "define <2 x i8> @test(<2 x i1> %x, <2 x i8> %y, <2 x i8> %z) {\n"
+ " %v0 = shufflevector <2 x i1> %x, <2 x i1> undef, <2 x i32> <i32 1, i32 1>\n"
+ " %v1 = shufflevector <2 x i8> %y, <2 x i8> undef, <2 x i32> <i32 0, i32 0>\n"
+ " %A = select <2 x i1> %v0, <2 x i8> %v1, <2 x i8> %z\n"
+ " ret <2 x i8> %A\n"
+ "}\n");
+ EXPECT_FALSE(isSplatValue(A));
+}
+
+TEST_F(VectorUtilsTest, isSplatValue_SelectBinop) {
+ parseAssembly(
+ "define <2 x i8> @test(<2 x i1> %x, <2 x i8> %y, <2 x i8> %z) {\n"
+ " %v0 = shufflevector <2 x i1> %x, <2 x i1> undef, <2 x i32> <i32 1, i32 1>\n"
+ " %v1 = shufflevector <2 x i8> %y, <2 x i8> undef, <2 x i32> <i32 0, i32 0>\n"
+ " %v2 = shufflevector <2 x i8> %z, <2 x i8> undef, <2 x i32> <i32 1, i32 1>\n"
+ " %bo = xor <2 x i8> %v1, %v2\n"
+ " %A = select <2 x i1> %v0, <2 x i8> %bo, <2 x i8> %v2\n"
+ " ret <2 x i8> %A\n"
+ "}\n");
+ EXPECT_TRUE(isSplatValue(A));
+}
+
TEST_F(VectorUtilsTest, getSplatValueElt0) {
parseAssembly(
"define <2 x i8> @test(i8 %x) {\n"
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