[GISel]: Add pattern matcher for FMUL and FADD

[aditya_nandakumar]

Summary

Just adding patterns as we need them (out of tree target) with test cases.

[qcolombet]

include/llvm/CodeGen/GlobalISel/MIPatternMatch.h

202

This should be its own separate commit.

[aditya_nandakumar]

Thanks. Submitted in r325043 and r325044

include/llvm/CodeGen/GlobalISel/MIPatternMatch.h

 
 template <typename LHS, typename RHS>
 inline BinaryOp_match<LHS, RHS, TargetOpcode::G_MUL, true>
 m_GMul(const LHS &L, const RHS &R) {
   return BinaryOp_match<LHS, RHS, TargetOpcode::G_MUL, true>(L, R);
 }
 
 template <typename LHS, typename RHS>
-inline BinaryOp_match<LHS, RHS, TargetOpcode::G_FADD> m_GFAdd(const LHS &L,
-                                                              const RHS &R) {
-  return BinaryOp_match<LHS, RHS, TargetOpcode::G_FADD>(L, R);
+inline BinaryOp_match<LHS, RHS, TargetOpcode::G_FADD, true>
+m_GFAdd(const LHS &L, const RHS &R) {
+  return BinaryOp_match<LHS, RHS, TargetOpcode::G_FADD, true>(L, R);
+}
+
+template <typename LHS, typename RHS>
+inline BinaryOp_match<LHS, RHS, TargetOpcode::G_FMUL, true>
+m_GFMul(const LHS &L, const RHS &R) {
+  return BinaryOp_match<LHS, RHS, TargetOpcode::G_FMUL, true>(L, R);
 }
 
 // Helper for unary instructions (G_[ZSA]EXT/G_TRUNC) etc
 template <typename SrcTy, unsigned Opcode> struct UnaryOp_match {
   SrcTy L;
 
   UnaryOp_match(const SrcTy &LHS) : L(LHS) {}
   template <typename OpTy> bool match(MachineRegisterInfo &MRI, OpTy &&Op) {

unittests/CodeGen/GlobalISel/PatternMatchTest.cpp

TEST(PatternMatchInstr, MatchBinaryOp) {
   ASSERT_EQ(Cst, (uint64_t)42);
   ASSERT_EQ(Src0, Copies[0]);
 
   // Make sure commutative doesn't work with something like SUB.
   auto MIBSub = B.buildSub(s64, Copies[0], B.buildConstant(s64, 42));
   match = mi_match(MIBSub->getOperand(0).getReg(), MRI,
                    m_GSub(m_ICst(Cst), m_Reg(Src0)));
   ASSERT_FALSE(match);
+
+  auto MIBFMul = B.buildInstr(TargetOpcode::G_FMUL, s64, Copies[0],
+                              B.buildConstant(s64, 42));
+  // Match and test commutativity for FMUL.
+  match = mi_match(MIBFMul->getOperand(0).getReg(), MRI,
+                   m_GFMul(m_ICst(Cst), m_Reg(Src0)));
+  ASSERT_TRUE(match);
+  ASSERT_EQ(Cst, (uint64_t)42);
+  ASSERT_EQ(Src0, Copies[0]);
 }
 
 TEST(PatternMatchInstr, MatchExtendsTrunc) {
   LLVMContext Context;
   std::unique_ptr<TargetMachine> TM = createTargetMachine();
   if (!TM)
     return;
   auto ModuleMMIPair = createDummyModule(Context, *TM, "");