[clang] [clang] Lower _BitInt(129+) to a different type in LLVM IR (PR #91364)

[John McCall via cfe-commits]

================
@@ -2012,26 +2015,27 @@ llvm::Value *CodeGenFunction::EmitLoadOfScalar(Address Addr, bool Volatile,
 }
 
 llvm::Value *CodeGenFunction::EmitToMemory(llvm::Value *Value, QualType Ty) {
-  // Bool has a different representation in memory than in registers.
-  if (hasBooleanRepresentation(Ty)) {
-    // This should really always be an i1, but sometimes it's already
-    // an i8, and it's awkward to track those cases down.
-    if (Value->getType()->isIntegerTy(1))
-      return Builder.CreateZExt(Value, ConvertTypeForMem(Ty), "frombool");
-    assert(Value->getType()->isIntegerTy(getContext().getTypeSize(Ty)) &&
-           "wrong value rep of bool");
+  if (hasBooleanRepresentation(Ty) ||
+      (Ty->isBitIntType() && Value->getType()->isIntegerTy())) {
+    llvm::Type *StoreTy = convertTypeForLoadStore(Ty, Value->getType());
+    bool Signed = Ty->isSignedIntegerOrEnumerationType();
+    return Builder.CreateIntCast(Value, StoreTy, Signed, "storedv");
+  }
+
+  if (Ty->isExtVectorBoolType()) {
+    llvm::Type *StoreTy = convertTypeForLoadStore(Ty, Value->getType());
+    // Expand to the memory bit width.
+    unsigned MemNumElems = StoreTy->getPrimitiveSizeInBits();
+    // <N x i1> --> <P x i1>.
+    Value = emitBoolVecConversion(Value, MemNumElems, "insertvec");
+    // <P x i1> --> iP.
+    Value = Builder.CreateBitCast(Value, StoreTy);
   }
 
   return Value;
 }
 
 llvm::Value *CodeGenFunction::EmitFromMemory(llvm::Value *Value, QualType Ty) {
----------------
rjmccall wrote:

```suggestion
/// Converts a scalar value from its load/store type (as returned
/// by convertTypeForLoadStore) to its primary IR type (as returned
/// by converType).
llvm::Value *CodeGenFunction::EmitFromMemory(llvm::Value *Value, QualType Ty) {
```

https://github.com/llvm/llvm-project/pull/91364