diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.h b/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.h
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.h
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.h
@@ -74,6 +74,7 @@
   AMDGPUTTIImpl CommonTTI;
   bool IsGraphicsShader;
   bool HasFP32Denormals;
+  unsigned MaxVGPRs;
 
   const FeatureBitset InlineFeatureIgnoreList = {
     // Codegen control options which don't matter.
@@ -133,7 +134,11 @@
       TLI(ST->getTargetLowering()),
       CommonTTI(TM, F),
       IsGraphicsShader(AMDGPU::isShader(F.getCallingConv())),
-      HasFP32Denormals(AMDGPU::SIModeRegisterDefaults(F).allFP32Denormals()) {}
+      HasFP32Denormals(AMDGPU::SIModeRegisterDefaults(F).allFP32Denormals()),
+      MaxVGPRs(ST->getMaxNumVGPRs(
+          std::max(ST->getWavesPerEU(F).first,
+                   ST->getWavesPerEUForWorkGroup(
+                       ST->getFlatWorkGroupSizes(F).second)))) {}
 
   bool hasBranchDivergence() { return true; }
   bool useGPUDivergenceAnalysis() const;
@@ -148,6 +153,7 @@
 
   unsigned getHardwareNumberOfRegisters(bool Vector) const;
   unsigned getNumberOfRegisters(bool Vector) const;
+  unsigned getNumberOfRegisters(unsigned RCID) const;
   unsigned getRegisterBitWidth(bool Vector) const;
   unsigned getMinVectorRegisterBitWidth() const;
   unsigned getLoadVectorFactor(unsigned VF, unsigned LoadSize,
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp
@@ -239,7 +239,7 @@
 unsigned GCNTTIImpl::getHardwareNumberOfRegisters(bool Vec) const {
   // The concept of vector registers doesn't really exist. Some packed vector
   // operations operate on the normal 32-bit registers.
-  return 256;
+  return MaxVGPRs;
 }
 
 unsigned GCNTTIImpl::getNumberOfRegisters(bool Vec) const {
@@ -248,6 +248,13 @@
   return getHardwareNumberOfRegisters(Vec) >> 3;
 }
 
+unsigned GCNTTIImpl::getNumberOfRegisters(unsigned RCID) const {
+  const SIRegisterInfo *TRI = ST->getRegisterInfo();
+  const TargetRegisterClass *RC = TRI->getRegClass(RCID);
+  unsigned NumVGPRs = (TRI->getRegSizeInBits(*RC) + 31) / 32;
+  return getHardwareNumberOfRegisters(false) / NumVGPRs;
+}
+
 unsigned GCNTTIImpl::getRegisterBitWidth(bool Vector) const {
   return 32;
 }