commit 91fc4e09499c24e9184853e9a53a953bdea8a356
author Aditya Nandakumar <aditya_nandakumar@apple.com> Fri Mar 09 17:31:51 2018 +0000
committer Aditya Nandakumar <aditya_nandakumar@apple.com> Fri Mar 09 17:31:51 2018 +0000
tree 2ecf5eaad712fa1bda8e20854ff909d8b98c559f
parent 2e55ee77e2b9f0d13d4a85852059d258a697cc5c

[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

llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp

diff --git a/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp b/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
index 475bb82..a6c285a 100644
--- a/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
@@ -284,6 +284,14 @@
   return buildInstr(TargetOpcode::G_FCONSTANT).addDef(Res).addFPImm(&Val);
 }
 
+MachineInstrBuilder MachineIRBuilder::buildFConstant(unsigned Res, double Val) {
+  LLT DstTy = MRI->getType(Res);
+  auto &Ctx = MF->getFunction().getContext();
+  auto *CFP =
+      ConstantFP::get(Ctx, getAPFloatFromSize(Val, DstTy.getSizeInBits()));
+  return buildFConstant(Res, *CFP);
+}
+
 MachineInstrBuilder MachineIRBuilder::buildBrCond(unsigned Tst,
                                                   MachineBasicBlock &Dest) {
   assert(MRI->getType(Tst).isScalar() && "invalid operand type");

llvm/lib/CodeGen/GlobalISel/Utils.cpp

diff --git a/llvm/lib/CodeGen/GlobalISel/Utils.cpp b/llvm/lib/CodeGen/GlobalISel/Utils.cpp
index b34414b..f39b387 100644
--- a/llvm/lib/CodeGen/GlobalISel/Utils.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/Utils.cpp
@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/GlobalISel/Utils.h"
+#include "llvm/ADT/APFloat.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/CodeGen/GlobalISel/RegisterBankInfo.h"
 #include "llvm/CodeGen/MachineInstr.h"
@@ -212,3 +213,16 @@
   }
   return DefMI->getOpcode() == Opcode ? DefMI : nullptr;
 }
+
+APFloat llvm::getAPFloatFromSize(double Val, unsigned Size) {
+  if (Size == 32)
+    return APFloat(float(Val));
+  if (Size == 64)
+    return APFloat(Val);
+  if (Size != 16)
+    llvm_unreachable("Unsupported FPConstant size");
+  bool Ignored;
+  APFloat APF(Val);
+  APF.convert(APFloat::IEEEhalf(), APFloat::rmNearestTiesToEven, &Ignored);
+  return APF;
+}