Revert "AMDGPU: Fix handling of alignment padding in DAG argument lowering"

This reverts commit r337021.

WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x1415cd65 in void write_signed<long>(llvm::raw_ostream&, long, unsigned long, llvm::IntegerStyle) /code/llvm-project/llvm/lib/Support/NativeFormatting.cpp:95:7
    #1 0x1415c900 in llvm::write_integer(llvm::raw_ostream&, long, unsigned long, llvm::IntegerStyle) /code/llvm-project/llvm/lib/Support/NativeFormatting.cpp:121:3
    #2 0x1472357f in llvm::raw_ostream::operator<<(long) /code/llvm-project/llvm/lib/Support/raw_ostream.cpp:117:3
    #3 0x13bb9d4 in llvm::raw_ostream::operator<<(int) /code/llvm-project/llvm/include/llvm/Support/raw_ostream.h:210:18
    #4 0x3c2bc18 in void printField<unsigned int, &(amd_kernel_code_s::amd_kernel_code_version_major)>(llvm::StringRef, amd_kernel_code_s const&, llvm::raw_ostream&) /code/llvm-project/llvm/lib/Target/AMDGPU/Utils/AMDKernelCodeTUtils.cpp:78:23
    #5 0x3c250ba in llvm::printAmdKernelCodeField(amd_kernel_code_s const&, int, llvm::raw_ostream&) /code/llvm-project/llvm/lib/Target/AMDGPU/Utils/AMDKernelCodeTUtils.cpp:104:5
    #6 0x3c27ca3 in llvm::dumpAmdKernelCode(amd_kernel_code_s const*, llvm::raw_ostream&, char const*) /code/llvm-project/llvm/lib/Target/AMDGPU/Utils/AMDKernelCodeTUtils.cpp:113:5
    #7 0x3a46e6c in llvm::AMDGPUTargetAsmStreamer::EmitAMDKernelCodeT(amd_kernel_code_s const&) /code/llvm-project/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUTargetStreamer.cpp:161:3
    #8 0xd371e4 in llvm::AMDGPUAsmPrinter::EmitFunctionBodyStart() /code/llvm-project/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp:204:26

[...]

Uninitialized value was created by an allocation of 'KernelCode' in the stack frame of function '_ZN4llvm16AMDGPUAsmPrinter21EmitFunctionBodyStartEv'
    #0 0xd36650 in llvm::AMDGPUAsmPrinter::EmitFunctionBodyStart() /code/llvm-project/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp:192

llvm-svn: 337079
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp b/llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp
index 13b4b50..0574c99 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp
@@ -24,23 +24,16 @@
   NoSignedZerosFPMath(MF.getTarget().Options.NoSignedZerosFPMath),
   MemoryBound(false),
   WaveLimiter(false) {
-  const AMDGPUSubtarget &ST = AMDGPUSubtarget::get(MF);
-
   // FIXME: Should initialize KernArgSize based on ExplicitKernelArgOffset,
   // except reserved size is not correctly aligned.
-  const Function &F = MF.getFunction();
 
   if (auto *Resolver = MF.getMMI().getResolver()) {
     if (AMDGPUPerfHintAnalysis *PHA = static_cast<AMDGPUPerfHintAnalysis*>(
           Resolver->getAnalysisIfAvailable(&AMDGPUPerfHintAnalysisID, true))) {
-      MemoryBound = PHA->isMemoryBound(&F);
-      WaveLimiter = PHA->needsWaveLimiter(&F);
+      MemoryBound = PHA->isMemoryBound(&MF.getFunction());
+      WaveLimiter = PHA->needsWaveLimiter(&MF.getFunction());
     }
   }
-
-  CallingConv::ID CC = F.getCallingConv();
-  if (CC == CallingConv::AMDGPU_KERNEL || CC == CallingConv::SPIR_KERNEL)
-    ExplicitKernArgSize = ST.getExplicitKernArgSize(F, MaxKernArgAlign);
 }
 
 unsigned AMDGPUMachineFunction::allocateLDSGlobal(const DataLayout &DL,