From e79d92c592d75e210dbe3abe1a975e859d17e953 Mon Sep 17 00:00:00 2001 From: Arnold Schwaighofer Date: Sun, 5 May 2013 01:54:46 +0000 Subject: [PATCH] PatternMatch: Matcher for (un)ordered floating point min/max Add support for matching 'ordered' and 'unordered' floating point min/max constructs. In LLVM we can express min/max functions as a combination of compare and select. We have support for matching such constructs for integers but not for floating point. In floating point math there is no total order because of the presence of 'NaN'. Therefore, we have to be careful to preserve the original fcmp semantics when interpreting floating point compare select combinations as a minimum or maximum function. The resulting 'ordered/unordered' floating point maximum function has to select the same value as the select/fcmp combination it is based on. ordered_max(x,y) = max(x,y) iff x and y are not NaN, y otherwise unordered_max(x,y) = max(x,y) iff x and y are not NaN, x otherwise ordered_min(x,y) = min(x,y) iff x and y are not NaN, y otherwise unordered_min(x,y) = min(x,y) iff x and y are not NaN, x otherwise This matches the behavior of the underlying select(fcmp(olt/ult/.., L, R), L, R) construct. Any code using this predicate has to preserve this semantics. A follow-up patch will use this to implement floating point min/max reductions in the vectorizer. radar://13723044 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181143 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Support/PatternMatch.h | 110 ++++++++++-- unittests/IR/PatternMatch.cpp | 265 ++++++++++++++++++++++++++++ 2 files changed, 364 insertions(+), 11 deletions(-) create mode 100644 unittests/IR/PatternMatch.cpp diff --git a/include/llvm/Support/PatternMatch.h b/include/llvm/Support/PatternMatch.h index 9fbe4349b39..a83a0684620 100644 --- a/include/llvm/Support/PatternMatch.h +++ b/include/llvm/Support/PatternMatch.h @@ -830,7 +830,7 @@ inline brc_match m_Br(const Cond_t &C, BasicBlock *&T, BasicBlock *&F) { // Matchers for max/min idioms, eg: "select (sgt x, y), x, y" -> smax(x,y). // -template +template struct MaxMin_match { LHS_t L; RHS_t R; @@ -844,7 +844,7 @@ struct MaxMin_match { SelectInst *SI = dyn_cast(V); if (!SI) return false; - ICmpInst *Cmp = dyn_cast(SI->getCondition()); + CmpInst_t *Cmp = dyn_cast(SI->getCondition()); if (!Cmp) return false; // At this point we have a select conditioned on a comparison. Check that @@ -856,7 +856,7 @@ struct MaxMin_match { if ((TrueVal != LHS || FalseVal != RHS) && (TrueVal != RHS || FalseVal != LHS)) return false; - ICmpInst::Predicate Pred = LHS == TrueVal ? + typename CmpInst_t::Predicate Pred = LHS == TrueVal ? Cmp->getPredicate() : Cmp->getSwappedPredicate(); // Does "(x pred y) ? x : y" represent the desired max/min operation? if (!Pred_t::match(Pred)) @@ -894,28 +894,116 @@ struct umin_pred_ty { } }; +/// ofmax_pred_ty - Helper class for identifying ordered max predicates. +struct ofmax_pred_ty { + static bool match(FCmpInst::Predicate Pred) { + return Pred == CmpInst::FCMP_OGT || Pred == CmpInst::FCMP_OGE; + } +}; + +/// ofmin_pred_ty - Helper class for identifying ordered min predicates. +struct ofmin_pred_ty { + static bool match(FCmpInst::Predicate Pred) { + return Pred == CmpInst::FCMP_OLT || Pred == CmpInst::FCMP_OLE; + } +}; + +/// ufmax_pred_ty - Helper class for identifying unordered max predicates. +struct ufmax_pred_ty { + static bool match(FCmpInst::Predicate Pred) { + return Pred == CmpInst::FCMP_UGT || Pred == CmpInst::FCMP_UGE; + } +}; + +/// ufmin_pred_ty - Helper class for identifying unordered min predicates. +struct ufmin_pred_ty { + static bool match(FCmpInst::Predicate Pred) { + return Pred == CmpInst::FCMP_ULT || Pred == CmpInst::FCMP_ULE; + } +}; + template -inline MaxMin_match +inline MaxMin_match m_SMax(const LHS &L, const RHS &R) { - return MaxMin_match(L, R); + return MaxMin_match(L, R); } template -inline MaxMin_match +inline MaxMin_match m_SMin(const LHS &L, const RHS &R) { - return MaxMin_match(L, R); + return MaxMin_match(L, R); } template -inline MaxMin_match +inline MaxMin_match m_UMax(const LHS &L, const RHS &R) { - return MaxMin_match(L, R); + return MaxMin_match(L, R); } template -inline MaxMin_match +inline MaxMin_match m_UMin(const LHS &L, const RHS &R) { - return MaxMin_match(L, R); + return MaxMin_match(L, R); +} + +/// \brief Match an 'ordered' floating point maximum attribute. +/// Floating point has one special value 'NaN'. Therefore, there is no total +/// order. However, if we can ignore the 'NaN' value (for example, because of a +/// 'no-nans-float-math' flag) a combination of a fcmp and select has 'maximum' +/// semantics. In the presence of 'NaN' we have to preserve the original +/// select(fcmp(ogt/ge, L, R), L, R) semantics matched by this predicate. +/// +/// max(L, R) iff L and R are not NaN +/// m_OrdFMax(L, R) = R iff L or R are NaN +template +inline MaxMin_match +m_OrdFMax(const LHS &L, const RHS &R) { + return MaxMin_match(L, R); +} + +/// \brief Match an 'ordered' floating point minimum attribute. +/// Floating point has one special value 'NaN'. Therefore, there is no total +/// order. However, if we can ignore the 'NaN' value (for example, because of a +/// 'no-nans-float-math' flag) a combination of a fcmp and select has 'minimum' +/// semantics. In the presence of 'NaN' we have to preserve the original +/// select(fcmp(olt/le, L, R), L, R) semantics matched by this predicate. +/// +/// max(L, R) iff L and R are not NaN +/// m_OrdFMin(L, R) = R iff L or R are NaN +template +inline MaxMin_match +m_OrdFMin(const LHS &L, const RHS &R) { + return MaxMin_match(L, R); +} + +/// \brief Match an 'unordered' floating point maximum attribute. +/// Floating point has one special value 'NaN'. Therefore, there is no total +/// order. However, if we can ignore the 'NaN' value (for example, because of a +/// 'no-nans-float-math' flag) a combination of a fcmp and select has 'maximum' +/// semantics. In the presence of 'NaN' we have to preserve the original +/// select(fcmp(ugt/ge, L, R), L, R) semantics matched by this predicate. +/// +/// max(L, R) iff L and R are not NaN +/// m_UnordFMin(L, R) = L iff L or R are NaN +template +inline MaxMin_match +m_UnordFMax(const LHS &L, const RHS &R) { + return MaxMin_match(L, R); +} + +/// \brief Match an 'unordered' floating point minimum attribute. +/// Floating point has one special value 'NaN'. Therefore, there is no total +/// order. However, if we can ignore the 'NaN' value (for example, because of a +/// 'no-nans-float-math' flag) a combination of a fcmp and select has 'minimum' +/// semantics. In the presence of 'NaN' we have to preserve the original +/// select(fcmp(ult/le, L, R), L, R) semantics matched by this predicate. +/// +/// max(L, R) iff L and R are not NaN +/// m_UnordFMin(L, R) = L iff L or R are NaN +template +inline MaxMin_match +m_UnordFMin(const LHS &L, const RHS &R) { + return MaxMin_match(L, R); } template diff --git a/unittests/IR/PatternMatch.cpp b/unittests/IR/PatternMatch.cpp new file mode 100644 index 00000000000..7c6d8ce6158 --- /dev/null +++ b/unittests/IR/PatternMatch.cpp @@ -0,0 +1,265 @@ +//===---- llvm/unittest/IR/PatternMatch.cpp - PatternMatch unit tests ----===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#include "llvm/ADT/STLExtras.h" +#include "llvm/Analysis/ValueTracking.h" +#include "llvm/IR/BasicBlock.h" +#include "llvm/IR/Constants.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/DerivedTypes.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/IRBuilder.h" +#include "llvm/IR/LLVMContext.h" +#include "llvm/IR/MDBuilder.h" +#include "llvm/IR/Operator.h" +#include "llvm/Support/NoFolder.h" +#include "llvm/Support/PatternMatch.h" +#include "gtest/gtest.h" + +using namespace llvm::PatternMatch; + +namespace llvm { +namespace { + +/// Ordered floating point minimum/maximum tests. + +static void m_OrdFMin_expect_match_and_delete(Value *Cmp, Value *Select, + Value *L, Value *R) { + Value *MatchL, *MatchR; + EXPECT_TRUE(m_OrdFMin(m_Value(MatchL), m_Value(MatchR)).match(Select)); + EXPECT_EQ(L, MatchL); + EXPECT_EQ(R, MatchR); + delete Select; + delete Cmp; +} + +static void m_OrdFMin_expect_nomatch_and_delete(Value *Cmp, Value *Select, + Value *L, Value *R) { + Value *MatchL, *MatchR; + EXPECT_FALSE(m_OrdFMin(m_Value(MatchL), m_Value(MatchR)).match(Select)); + delete Select; + delete Cmp; +} + +static void m_OrdFMax_expect_match_and_delete(Value *Cmp, Value *Select, + Value *L, Value *R) { + Value *MatchL, *MatchR; + EXPECT_TRUE(m_OrdFMax(m_Value(MatchL), m_Value(MatchR)).match(Select)); + EXPECT_EQ(L, MatchL); + EXPECT_EQ(R, MatchR); + delete Select; + delete Cmp; +} + +static void m_OrdFMax_expect_nomatch_and_delete(Value *Cmp, Value *Select, + Value *L, Value *R) { + Value *MatchL, *MatchR; + EXPECT_FALSE(m_OrdFMax(m_Value(MatchL), m_Value(MatchR)).match(Select)); + delete Select; + delete Cmp; +} + + + +TEST(PatternMatchTest, FloatingPointOrderedMin) { + LLVMContext &C(getGlobalContext()); + IRBuilder Builder(C); + + Type *FltTy = Builder.getFloatTy(); + Value *L = ConstantFP::get(FltTy, 1.0); + Value *R = ConstantFP::get(FltTy, 2.0); + + // Test OLT. + Value *Cmp = Builder.CreateFCmpOLT(L, R); + Value *Select = Builder.CreateSelect(Cmp, L, R); + m_OrdFMin_expect_match_and_delete(Cmp, Select, L, R); + + // Test OLE. + Cmp = Builder.CreateFCmpOLE(L, R); + Select = Builder.CreateSelect(Cmp, L, R); + m_OrdFMin_expect_match_and_delete(Cmp, Select, L, R); + + // Test no match on OGE. + Cmp = Builder.CreateFCmpOGE(L, R); + Select = Builder.CreateSelect(Cmp, L, R); + m_OrdFMin_expect_nomatch_and_delete(Cmp, Select, L, R); + + // Test no match on OGT. + Cmp = Builder.CreateFCmpOGT(L, R); + Select = Builder.CreateSelect(Cmp, L, R); + m_OrdFMin_expect_nomatch_and_delete(Cmp, Select, L, R); + + // Test match on OGE with inverted select. + Cmp = Builder.CreateFCmpOGE(L, R); + Select = Builder.CreateSelect(Cmp, R, L); + m_OrdFMin_expect_match_and_delete(Cmp, Select, L, R); + + // Test match on OGT with inverted select. + Cmp = Builder.CreateFCmpOGT(L, R); + Select = Builder.CreateSelect(Cmp, R, L); + m_OrdFMin_expect_match_and_delete(Cmp, Select, L, R); +} + +TEST(PatternMatchTest, FloatingPointOrderedMax) { + LLVMContext &C(getGlobalContext()); + IRBuilder Builder(C); + + Type *FltTy = Builder.getFloatTy(); + Value *L = ConstantFP::get(FltTy, 1.0); + Value *R = ConstantFP::get(FltTy, 2.0); + + // Test OGT. + Value *Cmp = Builder.CreateFCmpOGT(L, R); + Value *Select = Builder.CreateSelect(Cmp, L, R); + m_OrdFMax_expect_match_and_delete(Cmp, Select, L, R); + + // Test OGE. + Cmp = Builder.CreateFCmpOGE(L, R); + Select = Builder.CreateSelect(Cmp, L, R); + m_OrdFMax_expect_match_and_delete(Cmp, Select, L, R); + + // Test no match on OLE. + Cmp = Builder.CreateFCmpOLE(L, R); + Select = Builder.CreateSelect(Cmp, L, R); + m_OrdFMax_expect_nomatch_and_delete(Cmp, Select, L, R); + + // Test no match on OLT. + Cmp = Builder.CreateFCmpOLT(L, R); + Select = Builder.CreateSelect(Cmp, L, R); + m_OrdFMax_expect_nomatch_and_delete(Cmp, Select, L, R); + + // Test match on OLE with inverted select. + Cmp = Builder.CreateFCmpOLE(L, R); + Select = Builder.CreateSelect(Cmp, R, L); + m_OrdFMax_expect_match_and_delete(Cmp, Select, L, R); + + // Test match on OLT with inverted select. + Cmp = Builder.CreateFCmpOLT(L, R); + Select = Builder.CreateSelect(Cmp, R, L); + m_OrdFMax_expect_match_and_delete(Cmp, Select, L, R); +} + +/// Unordered floating point minimum/maximum tests. + +static void m_UnordFMin_expect_match_and_delete(Value *Cmp, Value *Select, + Value *L, Value *R) { + Value *MatchL, *MatchR; + EXPECT_TRUE(m_UnordFMin(m_Value(MatchL), m_Value(MatchR)).match(Select)); + EXPECT_EQ(L, MatchL); + EXPECT_EQ(R, MatchR); + delete Select; + delete Cmp; +} + +static void m_UnordFMin_expect_nomatch_and_delete(Value *Cmp, Value *Select, + Value *L, Value *R) { + Value *MatchL, *MatchR; + EXPECT_FALSE(m_UnordFMin(m_Value(MatchL), m_Value(MatchR)).match(Select)); + delete Select; + delete Cmp; +} + +static void m_UnordFMax_expect_match_and_delete(Value *Cmp, Value *Select, + Value *L, Value *R) { + Value *MatchL, *MatchR; + EXPECT_TRUE(m_UnordFMax(m_Value(MatchL), m_Value(MatchR)).match(Select)); + EXPECT_EQ(L, MatchL); + EXPECT_EQ(R, MatchR); + delete Select; + delete Cmp; +} + +static void m_UnordFMax_expect_nomatch_and_delete(Value *Cmp, Value *Select, + Value *L, Value *R) { + Value *MatchL, *MatchR; + EXPECT_FALSE(m_UnordFMax(m_Value(MatchL), m_Value(MatchR)).match(Select)); + delete Select; + delete Cmp; +} + +TEST(PatternMatchTest, FloatingPointUnorderedMin) { + LLVMContext &C(getGlobalContext()); + IRBuilder Builder(C); + + Type *FltTy = Builder.getFloatTy(); + Value *L = ConstantFP::get(FltTy, 1.0); + Value *R = ConstantFP::get(FltTy, 2.0); + + // Test ULT. + Value *Cmp = Builder.CreateFCmpULT(L, R); + Value *Select = Builder.CreateSelect(Cmp, L, R); + m_UnordFMin_expect_match_and_delete(Cmp, Select, L, R); + + // Test ULE. + Cmp = Builder.CreateFCmpULE(L, R); + Select = Builder.CreateSelect(Cmp, L, R); + m_UnordFMin_expect_match_and_delete(Cmp, Select, L, R); + + // Test no match on UGE. + Cmp = Builder.CreateFCmpUGE(L, R); + Select = Builder.CreateSelect(Cmp, L, R); + m_UnordFMin_expect_nomatch_and_delete(Cmp, Select, L, R); + + // Test no match on UGT. + Cmp = Builder.CreateFCmpUGT(L, R); + Select = Builder.CreateSelect(Cmp, L, R); + m_UnordFMin_expect_nomatch_and_delete(Cmp, Select, L, R); + + // Test match on UGE with inverted select. + Cmp = Builder.CreateFCmpUGE(L, R); + Select = Builder.CreateSelect(Cmp, R, L); + m_UnordFMin_expect_match_and_delete(Cmp, Select, L, R); + + // Test match on UGT with inverted select. + Cmp = Builder.CreateFCmpUGT(L, R); + Select = Builder.CreateSelect(Cmp, R, L); + m_UnordFMin_expect_match_and_delete(Cmp, Select, L, R); +} + +TEST(PatternMatchTest, FloatingPointUnorderedMax) { + LLVMContext &C(getGlobalContext()); + IRBuilder Builder(C); + + Type *FltTy = Builder.getFloatTy(); + Value *L = ConstantFP::get(FltTy, 1.0); + Value *R = ConstantFP::get(FltTy, 2.0); + + // Test UGT. + Value *Cmp = Builder.CreateFCmpUGT(L, R); + Value *Select = Builder.CreateSelect(Cmp, L, R); + m_UnordFMax_expect_match_and_delete(Cmp, Select, L, R); + + // Test UGE. + Cmp = Builder.CreateFCmpUGE(L, R); + Select = Builder.CreateSelect(Cmp, L, R); + m_UnordFMax_expect_match_and_delete(Cmp, Select, L, R); + + // Test no match on ULE. + Cmp = Builder.CreateFCmpULE(L, R); + Select = Builder.CreateSelect(Cmp, L, R); + m_UnordFMax_expect_nomatch_and_delete(Cmp, Select, L, R); + + // Test no match on ULT. + Cmp = Builder.CreateFCmpULT(L, R); + Select = Builder.CreateSelect(Cmp, L, R); + m_UnordFMax_expect_nomatch_and_delete(Cmp, Select, L, R); + + // Test match on ULE with inverted select. + Cmp = Builder.CreateFCmpULE(L, R); + Select = Builder.CreateSelect(Cmp, R, L); + m_UnordFMax_expect_match_and_delete(Cmp, Select, L, R); + + // Test match on ULT with inverted select. + Cmp = Builder.CreateFCmpULT(L, R); + Select = Builder.CreateSelect(Cmp, R, L); + m_UnordFMax_expect_match_and_delete(Cmp, Select, L, R); +} + +} // anonymous namespace. +} // llvm namespace.