InitializeStaticGlobals: handle InlineArray.init(repeating:) also for arm64_32

This needs matching a different builtin for scalar conversion for the `index_addr` index.

Fixes a test failure on watchos
rdar://151761870

Author: eeckstein

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/InitializeStaticGlobals.swift

@@ -399,7 +399,7 @@ private extension StoreInst {
        let headerBr = vectorBase.parentBlock.terminator as? BranchInst,
        headerBr.targetBlock == parentBlock,
        let vectorSize = vectorBase.vector.type.builtinFixedArraySizeType.valueOfInteger,
-       let (start, loopCount, increment) = getLoopInductionInfo(of: indexAddr.index.lookThroughTruncOrBitCast),
+       let (start, loopCount, increment) = getLoopInductionInfo(of: indexAddr.index.lookThroughIndexScalarCast),
        start == 0, loopCount == vectorSize, increment == 1
     {
       return true

SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyPointerToAddress.swift

@@ -69,7 +69,7 @@ private func removeAddressToPointerToAddressPair(
 ///
 private func simplifyIndexRawPointer(of ptr2Addr: PointerToAddressInst, _ context: SimplifyContext) -> Bool {
   guard let indexRawPtr = ptr2Addr.pointer as? IndexRawPointerInst,
-        let tupleExtract = indexRawPtr.index.lookThroughTruncOrBitCast as? TupleExtractInst,
+        let tupleExtract = indexRawPtr.index.lookThroughIndexScalarCast as? TupleExtractInst,
         let strideMul = tupleExtract.tuple as? BuiltinInst, strideMul.id == .SMulOver,
         let (index, strideType) = strideMul.indexAndStrideOfMultiplication,
         strideType == ptr2Addr.type.objectType

SwiftCompilerSources/Sources/Optimizer/Utilities/OptUtils.swift

@@ -45,9 +45,14 @@ extension Value {
     }
   }
 
-  var lookThroughTruncOrBitCast: Value {
-    if let truncOrBitCast = self as? BuiltinInst, truncOrBitCast.id == .TruncOrBitCast {
-      return truncOrBitCast.arguments[0]
+  var lookThroughIndexScalarCast: Value {
+    if let castBuiltin = self as? BuiltinInst {
+      switch castBuiltin.id {
+      case .TruncOrBitCast, .SExtOrBitCast:
+        return castBuiltin.arguments[0]
+      default:
+        return self
+      }
     }
     return self
   }