AMDGPU: Fix handling of alignment padding in DAG argument lowering

This was completely broken if there was ever a struct argument, as
this information is thrown away during the argument analysis.

The offsets as passed in to LowerFormalArguments are not useful,
as they partially depend on the legalized result register type,
and they don't consider the alignment in the first place.

Ignore the Ins array, and instead figure out from the raw IR type
what we need to do. This seems to fix the padding computation
if the DAG lowering is forced (and stops breaking arguments
following padded arguments if the arguments were only partially
lowered in the IR)

llvm-svn: 337021

1 files changed, 2 insertions, 3 deletions

diff --git a/llvm/lib/Target/AMDGPU/AMDGPULowerKernelArguments.cpp b/llvm/lib/Target/AMDGPU/AMDGPULowerKernelArguments.cpp
index 3c5760804b3..8cc7e38f7b2 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPULowerKernelArguments.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPULowerKernelArguments.cpp
@@ -77,8 +77,9 @@ bool AMDGPULowerKernelArguments::runOnFunction(Function &F) {
   const unsigned KernArgBaseAlign = 16; // FIXME: Increase if necessary
   const uint64_t BaseOffset = ST.getExplicitKernelArgOffset(F);
 
+  unsigned MaxAlign;
   // FIXME: Alignment is broken broken with explicit arg offset.;
-  const uint64_t TotalKernArgSize = ST.getKernArgSegmentSize(F);
+  const uint64_t TotalKernArgSize = ST.getKernArgSegmentSize(F, MaxAlign);
   if (TotalKernArgSize == 0)
     return false;
 
@@ -91,13 +92,11 @@ bool AMDGPULowerKernelArguments::runOnFunction(Function &F) {
     Attribute::getWithDereferenceableBytes(Ctx, TotalKernArgSize));
 
   unsigned AS = KernArgSegment->getType()->getPointerAddressSpace();
-  unsigned MaxAlign = 1;
   uint64_t ExplicitArgOffset = 0;
 
   for (Argument &Arg : F.args()) {
     Type *ArgTy = Arg.getType();
     unsigned Align = DL.getABITypeAlignment(ArgTy);
-    MaxAlign = std::max(Align, MaxAlign);
     unsigned Size = DL.getTypeSizeInBits(ArgTy);
     unsigned AllocSize = DL.getTypeAllocSize(ArgTy);