[PATCH] D156100: [AMDGPU] Have a command-line flag to enable true True16 codegen.

[Ivan Kosarev via Phabricator via llvm-commits]

kosarev created this revision.
kosarev added reviewers: arsenm, rampitec, Joe_Nash, foad.
Herald added subscribers: StephenFan, kerbowa, hiraditya, tpr, dstuttard, yaxunl, jvesely, kzhuravl.
Herald added a project: All.
kosarev requested review of this revision.
Herald added subscribers: llvm-commits, wdng.
Herald added a project: LLVM.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D156100

Files:
  llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
  llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
  llvm/lib/Target/AMDGPU/SIISelLowering.cpp


Index: llvm/lib/Target/AMDGPU/SIISelLowering.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -146,8 +146,13 @@
   addRegisterClass(MVT::v16f64, TRI->getVGPRClassForBitWidth(1024));
 
   if (Subtarget->has16BitInsts()) {
-    addRegisterClass(MVT::i16, &AMDGPU::SReg_32RegClass);
-    addRegisterClass(MVT::f16, &AMDGPU::SReg_32RegClass);
+    if (Subtarget->useTrue16BitInsts()) {
+      addRegisterClass(MVT::i16, &AMDGPU::VGPR_16RegClass);
+      addRegisterClass(MVT::f16, &AMDGPU::VGPR_16RegClass);
+    } else {
+      addRegisterClass(MVT::i16, &AMDGPU::SReg_32RegClass);
+      addRegisterClass(MVT::f16, &AMDGPU::SReg_32RegClass);
+    }
 
     // Unless there are also VOP3P operations, not operations are really legal.
     addRegisterClass(MVT::v2i16, &AMDGPU::SReg_32RegClass);
Index: llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
===================================================================
--- llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
+++ llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
@@ -155,6 +155,10 @@
 
   bool hasTrue16BitInsts() const { return HasTrue16BitInsts; }
 
+  // TODO: Remove and use hasTrue16BitInsts() instead once True16 is
+  // fully supported.
+  bool useTrue16BitInsts() const;
+
   bool hasMadMixInsts() const {
     return HasMadMixInsts;
   }
Index: llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
+++ llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
@@ -58,6 +58,10 @@
                                       cl::desc("Number of addresses from which to enable MIMG NSA."),
                                       cl::init(3), cl::Hidden);
 
+static cl::opt<bool> EnableTrue16Codegen("amdgpu-true16",
+                                         cl::desc("Use true 16-bit registers"),
+                                         cl::init(false), cl::ReallyHidden);
+
 GCNSubtarget::~GCNSubtarget() = default;
 
 GCNSubtarget &
@@ -166,6 +170,10 @@
 
 AMDGPUSubtarget::AMDGPUSubtarget(const Triple &TT) : TargetTriple(TT) {}
 
+bool AMDGPUSubtarget::useTrue16BitInsts() const {
+  return hasTrue16BitInsts() && EnableTrue16Codegen;
+}
+
 GCNSubtarget::GCNSubtarget(const Triple &TT, StringRef GPU, StringRef FS,
                            const GCNTargetMachine &TM)
     : // clang-format off


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