- Rename isLegalMemOpType to isSafeMemOpType. "Legal" is a very overloade term.

Also added more comments to explain why it is generally ok to return true.
- Rename getOptimalMemOpType argument IsZeroVal to ZeroOrLdSrc. It's meant to
be true for loaded source (memcpy) or zero constants (memset). The poor name
choice is probably some kind of legacy issue.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169954 91177308-0d34-0410-b5e6-96231b3b80d8

10 files changed, 34 insertions, 43 deletions

diff --git a/include/llvm/Target/TargetLowering.h b/include/llvm/Target/TargetLowering.h
index f301043851..3adf517e4a 100644
--- a/include/llvm/Target/TargetLowering.h
+++ b/include/llvm/Target/TargetLowering.h
@@ -702,7 +702,7 @@ public:
   /// alignment can satisfy any constraint. Similarly if SrcAlign is zero it
   /// means there isn't a need to check it against alignment requirement,
   /// probably because the source does not need to be loaded. If
-  /// 'IsZeroVal' is true, that means it's safe to return a
+  /// 'ZeroOrLdSrc' is true, that means it's safe to return a
   /// non-scalar-integer type, e.g. empty string source, constant, or loaded
   /// from memory. 'MemcpyStrSrc' indicates whether the memcpy source is
   /// constant so it does not need to be loaded.
@@ -710,19 +710,20 @@ public:
   /// target-independent logic.
   virtual EVT getOptimalMemOpType(uint64_t /*Size*/,
                                   unsigned /*DstAlign*/, unsigned /*SrcAlign*/,
-                                  bool /*IsZeroVal*/,
+                                  bool /*ZeroOrLdSrc*/,
                                   bool /*MemcpyStrSrc*/,
                                   MachineFunction &/*MF*/) const {
     return MVT::Other;
   }
 
-  /// isLegalMemOpType - Returns true if it's legal to use load / store of the
+  /// isSafeMemOpType - Returns true if it's safe to use load / store of the
   /// specified type to expand memcpy / memset inline. This is mostly true
-  /// for legal types except for some special cases. For example, on X86
+  /// for all types except for some special cases. For example, on X86
   /// targets without SSE2 f64 load / store are done with fldl / fstpl which
-  /// also does type conversion.
-  virtual bool isLegalMemOpType(MVT VT) const {
-    return VT.isInteger();
+  /// also does type conversion. Note the specified type doesn't have to be
+  /// legal as the hook is used before type legalization.
+  virtual bool isSafeMemOpType(MVT VT) const {
+    return true;
   }
 
   /// usesUnderscoreSetJmp - Determine if we should use _setjmp or setjmp
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 36592e54f8..754e6f352d 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -3426,7 +3426,7 @@ static bool isMemSrcFromString(SDValue Src, StringRef &Str) {
 static bool FindOptimalMemOpLowering(std::vector<EVT> &MemOps,
                                      unsigned Limit, uint64_t Size,
                                      unsigned DstAlign, unsigned SrcAlign,
-                                     bool IsZeroVal,
+                                     bool ZeroOrLdSrc,
                                      bool MemcpyStrSrc,
                                      bool AllowOverlap,
                                      SelectionDAG &DAG,
@@ -3441,7 +3441,7 @@ static bool FindOptimalMemOpLowering(std::vector<EVT> &MemOps,
   // 'MemcpyStrSrc' indicates whether the memcpy source is constant so it does
   // not need to be loaded.
   EVT VT = TLI.getOptimalMemOpType(Size, DstAlign, SrcAlign,
-                                   IsZeroVal, MemcpyStrSrc,
+                                   ZeroOrLdSrc, MemcpyStrSrc,
                                    DAG.getMachineFunction());
 
   if (VT == MVT::Other) {
@@ -3481,11 +3481,11 @@ static bool FindOptimalMemOpLowering(std::vector<EVT> &MemOps,
       if (VT.isVector() || VT.isFloatingPoint()) {
         NewVT = (VT.getSizeInBits() > 64) ? MVT::i64 : MVT::i32;
         if (TLI.isOperationLegalOrCustom(ISD::STORE, NewVT) &&
-            TLI.isLegalMemOpType(NewVT.getSimpleVT()))
+            TLI.isSafeMemOpType(NewVT.getSimpleVT()))
           Found = true;
         else if (NewVT == MVT::i64 &&
                  TLI.isOperationLegalOrCustom(ISD::STORE, MVT::f64) &&
-                 TLI.isLegalMemOpType(MVT::f64)) {
+                 TLI.isSafeMemOpType(MVT::f64)) {
           // i64 is usually not legal on 32-bit targets, but f64 may be.
           NewVT = MVT::f64;
           Found = true;
@@ -3497,7 +3497,7 @@ static bool FindOptimalMemOpLowering(std::vector<EVT> &MemOps,
           NewVT = (MVT::SimpleValueType)(NewVT.getSimpleVT().SimpleTy - 1);
           if (NewVT == MVT::i8)
             break;
-        } while (!TLI.isLegalMemOpType(NewVT.getSimpleVT()));
+        } while (!TLI.isSafeMemOpType(NewVT.getSimpleVT()));
       }
       NewVTSize = NewVT.getSizeInBits() / 8;
 
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index de7159e474..613df7a9b3 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -9450,13 +9450,13 @@ static bool memOpAlign(unsigned DstAlign, unsigned SrcAlign,
 
 EVT ARMTargetLowering::getOptimalMemOpType(uint64_t Size,
                                            unsigned DstAlign, unsigned SrcAlign,
-                                           bool IsZeroVal,
+                                           bool ZeroOrLdSrc,
                                            bool MemcpyStrSrc,
                                            MachineFunction &MF) const {
   const Function *F = MF.getFunction();
 
   // See if we can use NEON instructions for this...
-  if (IsZeroVal &&
+  if (ZeroOrLdSrc &&
       Subtarget->hasNEON() &&
       !F->getFnAttributes().hasAttribute(Attributes::NoImplicitFloat)) {
     bool Fast;
@@ -9481,10 +9481,6 @@ EVT ARMTargetLowering::getOptimalMemOpType(uint64_t Size,
   return MVT::Other;
 }
 
-bool ARMTargetLowering::isLegalMemOpType(MVT VT) const {
-  return VT.isInteger() || VT == MVT::f64 || VT == MVT::v2f64;
-}
-
 bool ARMTargetLowering::isZExtFree(SDValue Val, EVT VT2) const {
   if (Val.getOpcode() != ISD::LOAD)
     return false;
diff --git a/lib/Target/ARM/ARMISelLowering.h b/lib/Target/ARM/ARMISelLowering.h
index 3e78ae3b2d..59e2fd333f 100644
--- a/lib/Target/ARM/ARMISelLowering.h
+++ b/lib/Target/ARM/ARMISelLowering.h
@@ -292,17 +292,10 @@ namespace llvm {
 
     virtual EVT getOptimalMemOpType(uint64_t Size,
                                     unsigned DstAlign, unsigned SrcAlign,
-                                    bool IsZeroVal,
+                                    bool ZeroOrLdSrc,
                                     bool MemcpyStrSrc,
                                     MachineFunction &MF) const;
 
-    /// isLegalMemOpType - Returns true if it's legal to use load / store of the
-    /// specified type to expand memcpy / memset inline. This is mostly true
-    /// for legal types except for some special cases. For example, on X86
-    /// targets without SSE2 f64 load / store are done with fldl / fstpl which
-    /// also does type conversion.
-    virtual bool isLegalMemOpType(MVT VT) const;
-
     using TargetLowering::isZExtFree;
     virtual bool isZExtFree(SDValue Val, EVT VT2) const;
 
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index 619ae077b3..5edf82bc7f 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -3476,7 +3476,7 @@ MipsTargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
 }
 
 EVT MipsTargetLowering::getOptimalMemOpType(uint64_t Size, unsigned DstAlign,
-                                            unsigned SrcAlign, bool IsZeroVal,
+                                            unsigned SrcAlign, bool ZeroOrLdSrc,
                                             bool MemcpyStrSrc,
                                             MachineFunction &MF) const {
   if (Subtarget->hasMips64())
diff --git a/lib/Target/Mips/MipsISelLowering.h b/lib/Target/Mips/MipsISelLowering.h
index 4b318dc16f..46986613cb 100644
--- a/lib/Target/Mips/MipsISelLowering.h
+++ b/lib/Target/Mips/MipsISelLowering.h
@@ -362,7 +362,7 @@ namespace llvm {
     virtual bool isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const;
 
     virtual EVT getOptimalMemOpType(uint64_t Size, unsigned DstAlign,
-                                    unsigned SrcAlign, bool IsZeroVal,
+                                    unsigned SrcAlign, bool ZeroOrLdSrc,
                                     bool MemcpyStrSrc,
                                     MachineFunction &MF) const;
 
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 51f2192371..59aaf6db04 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -6815,7 +6815,7 @@ PPCTargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
 /// alignment can satisfy any constraint. Similarly if SrcAlign is zero it
 /// means there isn't a need to check it against alignment requirement,
 /// probably because the source does not need to be loaded. If
-/// 'IsZeroVal' is true, that means it's safe to return a
+/// 'ZeroOrLdSrc' is true, that means it's safe to return a
 /// non-scalar-integer type, e.g. empty string source, constant, or loaded
 /// from memory. 'MemcpyStrSrc' indicates whether the memcpy source is
 /// constant so it does not need to be loaded.
@@ -6823,7 +6823,7 @@ PPCTargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
 /// target-independent logic.
 EVT PPCTargetLowering::getOptimalMemOpType(uint64_t Size,
                                            unsigned DstAlign, unsigned SrcAlign,
-                                           bool IsZeroVal,
+                                           bool ZeroOrLdSrc,
                                            bool MemcpyStrSrc,
                                            MachineFunction &MF) const {
   if (this->PPCSubTarget.isPPC64()) {
diff --git a/lib/Target/PowerPC/PPCISelLowering.h b/lib/Target/PowerPC/PPCISelLowering.h
index 9f15eb89d5..a90118d3d0 100644
--- a/lib/Target/PowerPC/PPCISelLowering.h
+++ b/lib/Target/PowerPC/PPCISelLowering.h
@@ -401,7 +401,7 @@ namespace llvm {
     /// alignment can satisfy any constraint. Similarly if SrcAlign is zero it
     /// means there isn't a need to check it against alignment requirement,
     /// probably because the source does not need to be loaded. If
-    /// 'IsZeroVal' is true, that means it's safe to return a
+    /// 'ZeroOrLdSrc' is true, that means it's safe to return a
     /// non-scalar-integer type, e.g. empty string source, constant, or loaded
     /// from memory. 'MemcpyStrSrc' indicates whether the memcpy source is
     /// constant so it does not need to be loaded.
@@ -409,7 +409,7 @@ namespace llvm {
     /// target-independent logic.
     virtual EVT
     getOptimalMemOpType(uint64_t Size, unsigned DstAlign, unsigned SrcAlign,
-                        bool IsZeroVal, bool MemcpyStrSrc,
+                        bool ZeroOrLdSrc, bool MemcpyStrSrc,
                         MachineFunction &MF) const;
 
     /// isFMAFasterThanMulAndAdd - Return true if an FMA operation is faster than
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 800c2012df..f87d1fcb88 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1370,7 +1370,7 @@ unsigned X86TargetLowering::getByValTypeAlignment(Type *Ty) const {
 /// alignment can satisfy any constraint. Similarly if SrcAlign is zero it
 /// means there isn't a need to check it against alignment requirement,
 /// probably because the source does not need to be loaded. If
-/// 'IsZeroVal' is true, that means it's safe to return a
+/// 'ZeroOrLdSrc' is true, that means it's safe to return a
 /// non-scalar-integer type, e.g. empty string source, constant, or loaded
 /// from memory. 'MemcpyStrSrc' indicates whether the memcpy source is
 /// constant so it does not need to be loaded.
@@ -1379,11 +1379,11 @@ unsigned X86TargetLowering::getByValTypeAlignment(Type *Ty) const {
 EVT
 X86TargetLowering::getOptimalMemOpType(uint64_t Size,
                                        unsigned DstAlign, unsigned SrcAlign,
-                                       bool IsZeroVal,
+                                       bool ZeroOrLdSrc,
                                        bool MemcpyStrSrc,
                                        MachineFunction &MF) const {
   const Function *F = MF.getFunction();
-  if (IsZeroVal &&
+  if (ZeroOrLdSrc &&
       !F->getFnAttributes().hasAttribute(Attributes::NoImplicitFloat)) {
     if (Size >= 16 &&
         (Subtarget->isUnalignedMemAccessFast() ||
@@ -1412,12 +1412,12 @@ X86TargetLowering::getOptimalMemOpType(uint64_t Size,
   return MVT::i32;
 }
 
-bool X86TargetLowering::isLegalMemOpType(MVT VT) const {
+bool X86TargetLowering::isSafeMemOpType(MVT VT) const {
   if (VT == MVT::f32)
     return X86ScalarSSEf32;
   else if (VT == MVT::f64)
     return X86ScalarSSEf64;
-  return VT.isInteger();
+  return true;
 }
 
 bool
diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index 9d22da1dd9..601ed2b120 100644
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -495,7 +495,7 @@ namespace llvm {
     /// alignment can satisfy any constraint. Similarly if SrcAlign is zero it
     /// means there isn't a need to check it against alignment requirement,
     /// probably because the source does not need to be loaded. If
-    /// 'IsZeroVal' is true, that means it's safe to return a
+    /// 'ZeroOrLdSrc' is true, that means it's safe to return a
     /// non-scalar-integer type, e.g. empty string source, constant, or loaded
     /// from memory. 'MemcpyStrSrc' indicates whether the memcpy source is
     /// constant so it does not need to be loaded.
@@ -503,15 +503,16 @@ namespace llvm {
     /// target-independent logic.
     virtual EVT
     getOptimalMemOpType(uint64_t Size, unsigned DstAlign, unsigned SrcAlign,
-                        bool IsZeroVal, bool MemcpyStrSrc,
+                        bool ZeroOrLdSrc, bool MemcpyStrSrc,
                         MachineFunction &MF) const;
 
-    /// isLegalMemOpType - Returns true if it's legal to use load / store of the
+    /// isSafeMemOpType - Returns true if it's safe to use load / store of the
     /// specified type to expand memcpy / memset inline. This is mostly true
-    /// for legal types except for some special cases. For example, on X86
+    /// for all types except for some special cases. For example, on X86
     /// targets without SSE2 f64 load / store are done with fldl / fstpl which
-    /// also does type conversion.
-    virtual bool isLegalMemOpType(MVT VT) const;
+    /// also does type conversion. Note the specified type doesn't have to be
+    /// legal as the hook is used before type legalization.
+    virtual bool isSafeMemOpType(MVT VT) const;
 
     /// allowsUnalignedMemoryAccesses - Returns true if the target allows
     /// unaligned memory accesses. of the specified type. Returns whether it