[llvm] [AMDGPU] Check noalias.addrspace in mayAccessScratchThroughFlat (PR #151319)

[Pierre van Houtryve via llvm-commits]

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@@ -1630,6 +1631,22 @@ getIntegerVecAttribute(const Function &F, StringRef Name, unsigned Size) {
   return Vals;
 }
 
+bool hasValueInRange(const MDNode *MD, unsigned Val) {
+  if (!MD)
+    return false;
+
+  assert((MD->getNumOperands() % 2 == 0) && "invalid number of operands!");
+  for (unsigned I = 0, E = MD->getNumOperands() / 2; I != E; ++I) {
+    auto *Low = mdconst::extract<ConstantInt>(MD->getOperand(2 * I + 0));
+    auto *High = mdconst::extract<ConstantInt>(MD->getOperand(2 * I + 1));
+    assert(Low->getValue().ult(High->getValue()) && "invalid range metadata!");
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Pierre-vh wrote:

@arsenm There is a test that has a "wrapped" range: llvm/test/Transforms/AtomicExpand/AMDGPU/expand-cmpxchg-flat-maybe-private.ll

`noalias.addrspace` there has a value of `[6;5)`.
I guess this is a different way to say "everything is noalias except private" ? 
If so then I need to replace that assert with a if/else to handle such ranges

https://github.com/llvm/llvm-project/pull/151319