AMDGPU: Add D16 instructions preserve unused bits feature

- Predicate D16 patterns on this new feature
- Added this new feature to gfx900/2/4

Differential Revision: https://reviews.llvm.org/D46366

llvm-svn: 331551

Author: kzhuravl

llvm/lib/Target/AMDGPU/AMDGPU.td

@@ -322,6 +322,13 @@ def FeatureDLInsts : SubtargetFeature<"dl-insts",
   "Has deep learning instructions"
 >;
 
+def FeatureD16PreservesUnusedBits : SubtargetFeature<
+  "d16-preserves-unused-bits",
+  "D16PreservesUnusedBits",
+  "true",
+  "D16 memory instructions preserve unused bits rather than zeroing them out"
+>;
+
 //===------------------------------------------------------------===//
 // Subtarget Features (options and debugging)
 //===------------------------------------------------------------===//
@@ -608,20 +615,23 @@ def FeatureISAVersion8_1_0 : SubtargetFeatureISAVersion <8,1,0,
 def FeatureISAVersion9_0_0 : SubtargetFeatureISAVersion <9,0,0,
   [FeatureGFX9,
    FeatureMadMixInsts,
-   FeatureLDSBankCount32
+   FeatureLDSBankCount32,
+   FeatureD16PreservesUnusedBits
    ]>;
 
 def FeatureISAVersion9_0_2 : SubtargetFeatureISAVersion <9,0,2,
   [FeatureGFX9,
    FeatureMadMixInsts,
    FeatureLDSBankCount32,
-   FeatureXNACK
+   FeatureXNACK,
+   FeatureD16PreservesUnusedBits
    ]>;
 
 def FeatureISAVersion9_0_4 : SubtargetFeatureISAVersion <9,0,4,
   [FeatureGFX9,
    FeatureLDSBankCount32,
-   FeatureFmaMixInsts]>;
+   FeatureFmaMixInsts,
+   FeatureD16PreservesUnusedBits]>;
 
 def FeatureISAVersion9_0_6 : SubtargetFeatureISAVersion <9,0,6,
   [FeatureGFX9,
@@ -769,6 +779,8 @@ def HasUnpackedD16VMem : Predicate<"Subtarget->hasUnpackedD16VMem()">,
 def HasPackedD16VMem : Predicate<"!Subtarget->hasUnpackedD16VMem()">,
   AssemblerPredicate<"!FeatureUnpackedD16VMem">;
 
+def D16PreservesUnusedBits : Predicate<"Subtarget->d16PreservesUnusedBits()">,
+  AssemblerPredicate<"FeatureD16PreservesUnusedBits">;
 
 def LDSRequiresM0Init : Predicate<"Subtarget->ldsRequiresM0Init()">;
 def NotLDSRequiresM0Init : Predicate<"!Subtarget->ldsRequiresM0Init()">;

llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp

@@ -162,6 +162,7 @@ AMDGPUSubtarget::AMDGPUSubtarget(const Triple &TT, StringRef GPU, StringRef FS,
     HasSDWAOutModsVOPC(false),
     HasDPP(false),
     HasDLInsts(false),
+    D16PreservesUnusedBits(false),
     FlatAddressSpace(false),
     FlatInstOffsets(false),
     FlatGlobalInsts(false),

llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h

@@ -166,6 +166,7 @@ class AMDGPUSubtarget : public AMDGPUGenSubtargetInfo {
   bool HasSDWAOutModsVOPC;
   bool HasDPP;
   bool HasDLInsts;
+  bool D16PreservesUnusedBits;
   bool FlatAddressSpace;
   bool FlatInstOffsets;
   bool FlatGlobalInsts;
@@ -546,6 +547,10 @@ class AMDGPUSubtarget : public AMDGPUGenSubtargetInfo {
     return HasDLInsts;
   }
 
+  bool d16PreservesUnusedBits() const {
+    return D16PreservesUnusedBits;
+  }
+
   /// Returns the offset in bytes from the start of the input buffer
   ///        of the first explicit kernel argument.
   unsigned getExplicitKernelArgOffset(const MachineFunction &MF) const {

llvm/lib/Target/AMDGPU/BUFInstructions.td

@@ -1374,7 +1374,7 @@ defm : MUBUFScratchLoadPat <BUFFER_LOAD_DWORD_OFFEN, BUFFER_LOAD_DWORD_OFFSET, i
 defm : MUBUFScratchLoadPat <BUFFER_LOAD_DWORDX2_OFFEN, BUFFER_LOAD_DWORDX2_OFFSET, v2i32, load_private>;
 defm : MUBUFScratchLoadPat <BUFFER_LOAD_DWORDX4_OFFEN, BUFFER_LOAD_DWORDX4_OFFSET, v4i32, load_private>;
 
-let OtherPredicates = [HasD16LoadStore] in {
+let OtherPredicates = [D16PreservesUnusedBits] in {
 defm : MUBUFScratchLoadPat_Hi16<BUFFER_LOAD_SHORT_D16_HI_OFFEN, BUFFER_LOAD_SHORT_D16_HI_OFFSET, i16, load_private>;
 defm : MUBUFScratchLoadPat_Hi16<BUFFER_LOAD_UBYTE_D16_HI_OFFEN, BUFFER_LOAD_UBYTE_D16_HI_OFFSET, i16, az_extloadi8_private>;
 defm : MUBUFScratchLoadPat_Hi16<BUFFER_LOAD_SBYTE_D16_HI_OFFEN, BUFFER_LOAD_SBYTE_D16_HI_OFFSET, i16, sextloadi8_private>;
@@ -1489,7 +1489,7 @@ defm : MUBUFScratchStorePat <BUFFER_STORE_DWORDX2_OFFEN, BUFFER_STORE_DWORDX2_OF
 defm : MUBUFScratchStorePat <BUFFER_STORE_DWORDX4_OFFEN, BUFFER_STORE_DWORDX4_OFFSET, v4i32, store_private>;
 
 
-let OtherPredicates = [HasD16LoadStore] in {
+let OtherPredicates = [D16PreservesUnusedBits] in {
  // Hiding the extract high pattern in the PatFrag seems to not
  // automatically increase the complexity.
 let AddedComplexity = 1 in {

llvm/lib/Target/AMDGPU/DSInstructions.td

@@ -655,7 +655,7 @@ defm : DSReadPat_mc <DS_READ_B128, v4i32, "load_align16_local">;
 
 } // End AddedComplexity = 100
 
-let OtherPredicates = [HasD16LoadStore] in {
+let OtherPredicates = [D16PreservesUnusedBits] in {
 let AddedComplexity = 100 in {
 defm : DSReadPat_Hi16<DS_READ_U16_D16_HI, load_local>;
 defm : DSReadPat_Hi16<DS_READ_U8_D16_HI, az_extloadi8_local>;
@@ -689,7 +689,7 @@ defm : DSWritePat_mc <DS_WRITE_B8, i16, "truncstorei8_local">;
 defm : DSWritePat_mc <DS_WRITE_B16, i16, "store_local">;
 defm : DSWritePat_mc <DS_WRITE_B32, i32, "store_local">;
 
-let OtherPredicates = [HasD16LoadStore] in {
+let OtherPredicates = [D16PreservesUnusedBits] in {
 def : DSWritePat <DS_WRITE_B16_D16_HI, i32, store_local_hi16>;
 def : DSWritePat <DS_WRITE_B8_D16_HI, i32, truncstorei8_local_hi16>;
 }

llvm/lib/Target/AMDGPU/FLATInstructions.td

@@ -780,7 +780,7 @@ def : FlatAtomicPat <FLAT_ATOMIC_XOR_X2_RTN, atomic_xor_global, i64>;
 def : FlatStorePat <FLAT_STORE_BYTE, truncstorei8_flat, i16>;
 def : FlatStorePat <FLAT_STORE_SHORT, store_flat, i16>;
 
-let OtherPredicates = [HasD16LoadStore] in {
+let OtherPredicates = [D16PreservesUnusedBits] in {
 def : FlatStorePat <FLAT_STORE_SHORT_D16_HI, truncstorei16_hi16_flat, i32>;
 def : FlatStorePat <FLAT_STORE_BYTE_D16_HI, truncstorei8_hi16_flat, i32>;
 
@@ -824,7 +824,7 @@ def : FlatStoreSignedPat <GLOBAL_STORE_DWORD, store_global, i32>;
 def : FlatStoreSignedPat <GLOBAL_STORE_DWORDX2, store_global, v2i32>;
 def : FlatStoreSignedPat <GLOBAL_STORE_DWORDX4, store_global, v4i32>;
 
-let OtherPredicates = [HasD16LoadStore] in {
+let OtherPredicates = [D16PreservesUnusedBits] in {
 def : FlatStoreSignedPat <GLOBAL_STORE_SHORT_D16_HI, truncstorei16_hi16_global, i32>;
 def : FlatStoreSignedPat <GLOBAL_STORE_BYTE_D16_HI, truncstorei8_hi16_global, i32>;