[globalisel][tablegen] Compute available feature bits correctly.

Summary:
Predicate<> now has a field to indicate how often it must be recomputed.
Currently, there are two frequencies, per-module (RecomputePerFunction==0)
and per-function (RecomputePerFunction==1). Per-function predicates are
currently recomputed more frequently than necessary since the only predicate
in this category is cheap to test. Per-module predicates are now computed in
getSubtargetImpl() while per-function predicates are computed in selectImpl().

Tablegen now manages the PredicateBitset internally. It should only be
necessary to add the required includes.

Also fixed a problem revealed by the test case where
constrainSelectedInstRegOperands() would attempt to tie operands that
BuildMI had already tied.

Reviewers: ab, qcolombet, t.p.northover, rovka, aditya_nandakumar

Reviewed By: rovka

Subscribers: kristof.beyls, igorb, llvm-commits

Differential Revision: https://reviews.llvm.org/D32491

llvm-svn: 301750

1 files changed, 7 insertions, 13 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp b/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp
index b0e0e3eb4ba..9bfd570e9a8 100644
--- a/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp
+++ b/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp
@@ -51,7 +51,6 @@ public:
                              const AArch64Subtarget &STI,
                              const AArch64RegisterBankInfo &RBI);
 
-  void beginFunction(const MachineFunction &MF) override;
   bool select(MachineInstr &I) const override;
 
 private:
@@ -74,12 +73,10 @@ private:
   const AArch64InstrInfo &TII;
   const AArch64RegisterInfo &TRI;
   const AArch64RegisterBankInfo &RBI;
-  bool ForCodeSize;
 
-  PredicateBitset AvailableFeatures;
-  PredicateBitset
-  computeAvailableFeatures(const MachineFunction *MF,
-                           const AArch64Subtarget *Subtarget) const;
+#define GET_GLOBALISEL_PREDICATES_DECL
+#include "AArch64GenGlobalISel.inc"
+#undef GET_GLOBALISEL_PREDICATES_DECL
 
 // We declare the temporaries used by selectImpl() in the class to minimize the
 // cost of constructing placeholder values.
@@ -98,7 +95,10 @@ AArch64InstructionSelector::AArch64InstructionSelector(
     const AArch64TargetMachine &TM, const AArch64Subtarget &STI,
     const AArch64RegisterBankInfo &RBI)
     : InstructionSelector(), TM(TM), STI(STI), TII(*STI.getInstrInfo()),
-      TRI(*STI.getRegisterInfo()), RBI(RBI), ForCodeSize(), AvailableFeatures()
+      TRI(*STI.getRegisterInfo()), RBI(RBI),
+#define GET_GLOBALISEL_PREDICATES_INIT
+#include "AArch64GenGlobalISel.inc"
+#undef GET_GLOBALISEL_PREDICATES_INIT
 #define GET_GLOBALISEL_TEMPORARIES_INIT
 #include "AArch64GenGlobalISel.inc"
 #undef GET_GLOBALISEL_TEMPORARIES_INIT
@@ -577,12 +577,6 @@ bool AArch64InstructionSelector::selectVaStartDarwin(
   return true;
 }
 
-void AArch64InstructionSelector::beginFunction(
-    const MachineFunction &MF) {
-  ForCodeSize = MF.getFunction()->optForSize();
-  AvailableFeatures = computeAvailableFeatures(&MF, &STI);
-}
-
 bool AArch64InstructionSelector::select(MachineInstr &I) const {
   assert(I.getParent() && "Instruction should be in a basic block!");
   assert(I.getParent()->getParent() && "Instruction should be in a function!");