Reapplying [FastISel][AArch64] Cleanup constant materialization code. NFCI.

[oota-llvm.git] / lib / Target / SystemZ / SystemZTargetMachine.cpp

diff --git a/lib/Target/SystemZ/SystemZTargetMachine.cpp b/lib/Target/SystemZ/SystemZTargetMachine.cpp
index 17450ee53e958eaa0a6de0deff4f27a8f8872ef7..a30b225e502f6087058bcd5655acf28c7aa79e80 100644 (file)
--- a/lib/Target/SystemZ/SystemZTargetMachine.cpp
+++ b/lib/Target/SystemZ/SystemZTargetMachine.cpp
@@ -10,6 +10,7 @@
 #include "SystemZTargetMachine.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/Support/TargetRegistry.h"
+#include "llvm/Transforms/Scalar.h"
 
 using namespace llvm;
 
@@ -21,18 +22,10 @@ extern "C" void LLVMInitializeSystemZTarget() {
 SystemZTargetMachine::SystemZTargetMachine(const Target &T, StringRef TT,
                                            StringRef CPU, StringRef FS,
                                            const TargetOptions &Options,
-                                           Reloc::Model RM,
-                                           CodeModel::Model CM,
+                                           Reloc::Model RM, CodeModel::Model CM,
                                            CodeGenOpt::Level OL)
-  : LLVMTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL),
-    Subtarget(TT, CPU, FS),
-    // Make sure that global data has at least 16 bits of alignment by default,
-    // so that we can refer to it using LARL.  We don't have any special
-    // requirements for stack variables though.
-    DL("E-p:64:64:64-i1:8:16-i8:8:16-i16:16-i32:32-i64:64"
-       "-f32:32-f64:64-f128:64-a0:8:16-n32:64"),
-    InstrInfo(*this), TLInfo(*this), TSInfo(*this),
-    FrameLowering(*this, Subtarget) {
+    : LLVMTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL),
+      Subtarget(TT, CPU, FS, *this) {
   initAsmInfo();
 }
 
@@ -47,15 +40,61 @@ public:
     return getTM<SystemZTargetMachine>();
   }
 
-  virtual bool addInstSelector();
+  void addIRPasses() override;
+  bool addInstSelector() override;
+  bool addPreSched2() override;
+  bool addPreEmitPass() override;
 };
 } // end anonymous namespace
 
+void SystemZPassConfig::addIRPasses() {
+  TargetPassConfig::addIRPasses();
+}
+
 bool SystemZPassConfig::addInstSelector() {
   addPass(createSystemZISelDag(getSystemZTargetMachine(), getOptLevel()));
   return false;
 }
 
+bool SystemZPassConfig::addPreSched2() {
+  if (getOptLevel() != CodeGenOpt::None &&
+      getSystemZTargetMachine().getSubtargetImpl()->hasLoadStoreOnCond())
+    addPass(&IfConverterID);
+  return true;
+}
+
+bool SystemZPassConfig::addPreEmitPass() {
+  // We eliminate comparisons here rather than earlier because some
+  // transformations can change the set of available CC values and we
+  // generally want those transformations to have priority.  This is
+  // especially true in the commonest case where the result of the comparison
+  // is used by a single in-range branch instruction, since we will then
+  // be able to fuse the compare and the branch instead.
+  //
+  // For example, two-address NILF can sometimes be converted into
+  // three-address RISBLG.  NILF produces a CC value that indicates whether
+  // the low word is zero, but RISBLG does not modify CC at all.  On the
+  // other hand, 64-bit ANDs like NILL can sometimes be converted to RISBG.
+  // The CC value produced by NILL isn't useful for our purposes, but the
+  // value produced by RISBG can be used for any comparison with zero
+  // (not just equality).  So there are some transformations that lose
+  // CC values (while still being worthwhile) and others that happen to make
+  // the CC result more useful than it was originally.
+  //
+  // Another reason is that we only want to use BRANCH ON COUNT in cases
+  // where we know that the count register is not going to be spilled.
+  //
+  // Doing it so late makes it more likely that a register will be reused
+  // between the comparison and the branch, but it isn't clear whether
+  // preventing that would be a win or not.
+  if (getOptLevel() != CodeGenOpt::None)
+    addPass(createSystemZElimComparePass(getSystemZTargetMachine()));
+  if (getOptLevel() != CodeGenOpt::None)
+    addPass(createSystemZShortenInstPass(getSystemZTargetMachine()));
+  addPass(createSystemZLongBranchPass(getSystemZTargetMachine()));
+  return true;
+}
+
 TargetPassConfig *SystemZTargetMachine::createPassConfig(PassManagerBase &PM) {
   return new SystemZPassConfig(this, PM);
 }