[GISel]: Add helpers for easy building G_FCONSTANT along with matchers

Added helpers to build G_FCONSTANT, along with matching ConstantFP and
unit tests for the same.

Sample usage.

auto MIB = Builder.buildFConstant(s32, 0.5); // Build IEEESingle
For Matching the above

const ConstantFP* Tmp;
mi_match(DstReg, MRI, m_GFCst(Tmp));

https://reviews.llvm.org/D44128
reviewed by: volkan

llvm-svn: 327152

1 files changed, 36 insertions, 0 deletions

diff --git a/llvm/unittests/CodeGen/GlobalISel/PatternMatchTest.cpp b/llvm/unittests/CodeGen/GlobalISel/PatternMatchTest.cpp
index 0816084c690..d402d0b1e11 100644
--- a/llvm/unittests/CodeGen/GlobalISel/PatternMatchTest.cpp
+++ b/llvm/unittests/CodeGen/GlobalISel/PatternMatchTest.cpp
@@ -257,6 +257,42 @@ TEST(PatternMatchInstr, MatchFPUnaryOp) {
   match = mi_match(MIBFabs->getOperand(0).getReg(), MRI, m_GFabs(m_Reg(Src)));
   ASSERT_TRUE(match);
   ASSERT_EQ(Src, Copy0s32->getOperand(0).getReg());
+
+  // Build and match FConstant.
+  auto MIBFCst = B.buildFConstant(s32, .5);
+  const ConstantFP *TmpFP{};
+  match = mi_match(MIBFCst->getOperand(0).getReg(), MRI, m_GFCst(TmpFP));
+  ASSERT_TRUE(match);
+  ASSERT_TRUE(TmpFP);
+  APFloat APF((float).5);
+  auto *CFP = ConstantFP::get(Context, APF);
+  ASSERT_EQ(CFP, TmpFP);
+
+  // Build double float.
+  LLT s64 = LLT::scalar(64);
+  auto MIBFCst64 = B.buildFConstant(s64, .5);
+  const ConstantFP *TmpFP64{};
+  match = mi_match(MIBFCst64->getOperand(0).getReg(), MRI, m_GFCst(TmpFP64));
+  ASSERT_TRUE(match);
+  ASSERT_TRUE(TmpFP64);
+  APFloat APF64(.5);
+  auto CFP64 = ConstantFP::get(Context, APF64);
+  ASSERT_EQ(CFP64, TmpFP64);
+  ASSERT_NE(TmpFP64, TmpFP);
+
+  // Build half float.
+  LLT s16 = LLT::scalar(16);
+  auto MIBFCst16 = B.buildFConstant(s16, .5);
+  const ConstantFP *TmpFP16{};
+  match = mi_match(MIBFCst16->getOperand(0).getReg(), MRI, m_GFCst(TmpFP16));
+  ASSERT_TRUE(match);
+  ASSERT_TRUE(TmpFP16);
+  bool Ignored;
+  APFloat APF16(.5);
+  APF16.convert(APFloat::IEEEhalf(), APFloat::rmNearestTiesToEven, &Ignored);
+  auto CFP16 = ConstantFP::get(Context, APF16);
+  ASSERT_EQ(TmpFP16, CFP16);
+  ASSERT_NE(TmpFP16, TmpFP);
 }
 
 TEST(PatternMatchInstr, MatchExtendsTrunc) {