- 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

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.
+  /// also does type conversion. Note the specified type doesn't have to be
-  virtual bool isLegalMemOpType(MVT VT) const {
+  /// legal as the hook is used before type legalization.
-    return VT.isInteger();
+  virtual bool isSafeMemOpType(MVT VT) const {
+    return true;
   }
 
   /// usesUnderscoreSetJmp - Determine if we should use _setjmp or setjmp

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;
 

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;

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;
 

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())

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;
 

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()) {

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

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

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.
+    /// also does type conversion. Note the specified type doesn't have to be
-    virtual bool isLegalMemOpType(MVT VT) const;
+    /// 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